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@@ -75,37 +75,34 @@ enum {
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/*
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- * Pipelined mode parameters.
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+ * Pipelined mode parameters.
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*
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- * We try to use the minimum number of stages which is enough to
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- * keep the tape constantly streaming. To accomplish that, we implement
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- * a feedback loop around the maximum number of stages:
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+ * We try to use the minimum number of stages which is enough to keep the tape
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+ * constantly streaming. To accomplish that, we implement a feedback loop around
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+ * the maximum number of stages:
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*
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- * We start from MIN maximum stages (we will not even use MIN stages
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- * if we don't need them), increment it by RATE*(MAX-MIN)
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- * whenever we sense that the pipeline is empty, until we reach
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- * the optimum value or until we reach MAX.
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+ * We start from MIN maximum stages (we will not even use MIN stages if we don't
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+ * need them), increment it by RATE*(MAX-MIN) whenever we sense that the
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+ * pipeline is empty, until we reach the optimum value or until we reach MAX.
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*
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- * Setting the following parameter to 0 is illegal: the pipelined mode
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- * cannot be disabled (idetape_calculate_speeds() divides by
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- * tape->max_stages.)
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+ * Setting the following parameter to 0 is illegal: the pipelined mode cannot be
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+ * disabled (idetape_calculate_speeds() divides by tape->max_stages.)
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*/
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#define IDETAPE_MIN_PIPELINE_STAGES 1
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#define IDETAPE_MAX_PIPELINE_STAGES 400
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#define IDETAPE_INCREASE_STAGES_RATE 20
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/*
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- * After each failed packet command we issue a request sense command
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- * and retry the packet command IDETAPE_MAX_PC_RETRIES times.
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+ * After each failed packet command we issue a request sense command and retry
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+ * the packet command IDETAPE_MAX_PC_RETRIES times.
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*
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- * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
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+ * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
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*/
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#define IDETAPE_MAX_PC_RETRIES 3
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/*
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- * With each packet command, we allocate a buffer of
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- * IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet
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- * commands (Not for READ/WRITE commands).
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+ * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
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+ * bytes. This is used for several packet commands (Not for READ/WRITE commands)
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*/
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#define IDETAPE_PC_BUFFER_SIZE 256
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@@ -124,48 +121,39 @@ enum {
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#define IDETAPE_WAIT_CMD (900*HZ)
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/*
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- * The following parameter is used to select the point in the internal
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- * tape fifo in which we will start to refill the buffer. Decreasing
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- * the following parameter will improve the system's latency and
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- * interactive response, while using a high value might improve system
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- * throughput.
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+ * The following parameter is used to select the point in the internal tape fifo
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+ * in which we will start to refill the buffer. Decreasing the following
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+ * parameter will improve the system's latency and interactive response, while
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+ * using a high value might improve system throughput.
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*/
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-#define IDETAPE_FIFO_THRESHOLD 2
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+#define IDETAPE_FIFO_THRESHOLD 2
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/*
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- * DSC polling parameters.
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+ * DSC polling parameters.
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*
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- * Polling for DSC (a single bit in the status register) is a very
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- * important function in ide-tape. There are two cases in which we
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- * poll for DSC:
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+ * Polling for DSC (a single bit in the status register) is a very important
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+ * function in ide-tape. There are two cases in which we poll for DSC:
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*
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- * 1. Before a read/write packet command, to ensure that we
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- * can transfer data from/to the tape's data buffers, without
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- * causing an actual media access. In case the tape is not
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- * ready yet, we take out our request from the device
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- * request queue, so that ide.c will service requests from
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- * the other device on the same interface meanwhile.
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+ * 1. Before a read/write packet command, to ensure that we can transfer data
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+ * from/to the tape's data buffers, without causing an actual media access.
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+ * In case the tape is not ready yet, we take out our request from the device
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+ * request queue, so that ide.c could service requests from the other device
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+ * on the same interface in the meantime.
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*
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- * 2. After the successful initialization of a "media access
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- * packet command", which is a command which can take a long
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- * time to complete (it can be several seconds or even an hour).
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+ * 2. After the successful initialization of a "media access packet command",
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+ * which is a command that can take a long time to complete (the interval can
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+ * range from several seconds to even an hour). Again, we postpone our request
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+ * in the middle to free the bus for the other device. The polling frequency
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+ * here should be lower than the read/write frequency since those media access
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+ * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
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+ * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
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+ * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
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*
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- * Again, we postpone our request in the middle to free the bus
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- * for the other device. The polling frequency here should be
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- * lower than the read/write frequency since those media access
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- * commands are slow. We start from a "fast" frequency -
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- * IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
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- * after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
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- * lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
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- *
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- * We also set a timeout for the timer, in case something goes wrong.
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- * The timeout should be longer then the maximum execution time of a
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- * tape operation.
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- */
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-
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-/*
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- * DSC timings.
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+ * We also set a timeout for the timer, in case something goes wrong. The
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+ * timeout should be longer then the maximum execution time of a tape operation.
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*/
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+
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+/* DSC timings. */
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#define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */
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#define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */
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#define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */
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@@ -176,15 +164,9 @@ enum {
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/*************************** End of tunable parameters ***********************/
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-/*
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- * Read/Write error simulation
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- */
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+/* Read/Write error simulation */
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#define SIMULATE_ERRORS 0
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-/*
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- * For general magnetic tape device compatibility.
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- */
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-
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/* tape directions */
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enum {
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IDETAPE_DIR_NONE = (1 << 0),
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@@ -199,24 +181,32 @@ struct idetape_bh {
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char *b_data;
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};
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-/*
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- * Our view of a packet command.
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- */
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typedef struct idetape_packet_command_s {
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- u8 c[12]; /* Actual packet bytes */
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- int retries; /* On each retry, we increment retries */
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- int error; /* Error code */
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- int request_transfer; /* Bytes to transfer */
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- int actually_transferred; /* Bytes actually transferred */
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- int buffer_size; /* Size of our data buffer */
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+ /* Actual packet bytes */
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+ u8 c[12];
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+ /* On each retry, we increment retries */
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+ int retries;
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+ /* Error code */
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+ int error;
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+ /* Bytes to transfer */
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+ int request_transfer;
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+ /* Bytes actually transferred */
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+ int actually_transferred;
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+ /* Size of our data buffer */
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+ int buffer_size;
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struct idetape_bh *bh;
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char *b_data;
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int b_count;
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- u8 *buffer; /* Data buffer */
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- u8 *current_position; /* Pointer into the above buffer */
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- ide_startstop_t (*callback) (ide_drive_t *); /* Called when this packet command is completed */
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- u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE]; /* Temporary buffer */
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- unsigned long flags; /* Status/Action bit flags: long for set_bit */
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+ /* Data buffer */
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+ u8 *buffer;
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+ /* Pointer into the above buffer */
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+ u8 *current_position;
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+ /* Called when this packet command is completed */
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+ ide_startstop_t (*callback) (ide_drive_t *);
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+ /* Temporary buffer */
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+ u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];
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+ /* Status/Action bit flags: long for set_bit */
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+ unsigned long flags;
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} idetape_pc_t;
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/*
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@@ -235,9 +225,7 @@ typedef struct idetape_packet_command_s {
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/* Data direction */
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#define PC_WRITING 5
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-/*
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- * A pipeline stage.
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- */
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+/* A pipeline stage. */
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typedef struct idetape_stage_s {
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struct request rq; /* The corresponding request */
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struct idetape_bh *bh; /* The data buffers */
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@@ -245,9 +233,8 @@ typedef struct idetape_stage_s {
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} idetape_stage_t;
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/*
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- * Most of our global data which we need to save even as we leave the
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- * driver due to an interrupt or a timer event is stored in a variable
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- * of type idetape_tape_t, defined below.
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+ * Most of our global data which we need to save even as we leave the driver due
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+ * to an interrupt or a timer event is stored in the struct defined below.
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*/
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typedef struct ide_tape_obj {
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ide_drive_t *drive;
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@@ -283,15 +270,14 @@ typedef struct ide_tape_obj {
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int rq_stack_index;
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/*
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- * DSC polling variables.
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+ * DSC polling variables.
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*
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- * While polling for DSC we use postponed_rq to postpone the
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- * current request so that ide.c will be able to service
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- * pending requests on the other device. Note that at most
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- * we will have only one DSC (usually data transfer) request
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- * in the device request queue. Additional requests can be
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- * queued in our internal pipeline, but they will be visible
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- * to ide.c only one at a time.
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+ * While polling for DSC we use postponed_rq to postpone the current
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+ * request so that ide.c will be able to service pending requests on the
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+ * other device. Note that at most we will have only one DSC (usually
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+ * data transfer) request in the device request queue. Additional
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+ * requests can be queued in our internal pipeline, but they will be
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+ * visible to ide.c only one at a time.
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*/
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struct request *postponed_rq;
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/* The time in which we started polling for DSC */
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@@ -303,21 +289,15 @@ typedef struct ide_tape_obj {
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unsigned long dsc_poll_freq;
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unsigned long dsc_timeout;
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- /*
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- * Read position information
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- */
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+ /* Read position information */
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u8 partition;
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/* Current block */
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unsigned int first_frame;
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- /*
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- * Last error information
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- */
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+ /* Last error information */
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u8 sense_key, asc, ascq;
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- /*
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- * Character device operation
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- */
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+ /* Character device operation */
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unsigned int minor;
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/* device name */
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char name[4];
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@@ -332,33 +312,30 @@ typedef struct ide_tape_obj {
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u8 caps[20];
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/*
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- * Active data transfer request parameters.
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- *
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- * At most, there is only one ide-tape originated data transfer
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- * request in the device request queue. This allows ide.c to
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- * easily service requests from the other device when we
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- * postpone our active request. In the pipelined operation
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- * mode, we use our internal pipeline structure to hold
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- * more data requests.
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+ * Active data transfer request parameters.
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*
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- * The data buffer size is chosen based on the tape's
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- * recommendation.
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+ * At most, there is only one ide-tape originated data transfer request
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+ * in the device request queue. This allows ide.c to easily service
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+ * requests from the other device when we postpone our active request.
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+ * In the pipelined operation mode, we use our internal pipeline
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+ * structure to hold more data requests. The data buffer size is chosen
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+ * based on the tape's recommendation.
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*/
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- /* Ptr to the request which is waiting in the device request queue */
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+ /* ptr to the request which is waiting in the device request queue */
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struct request *active_data_rq;
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- /* Data buffer size (chosen based on the tape's recommendation */
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+ /* Data buffer size chosen based on the tape's recommendation */
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int stage_size;
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idetape_stage_t *merge_stage;
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int merge_stage_size;
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struct idetape_bh *bh;
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char *b_data;
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int b_count;
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-
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+
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/*
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- * Pipeline parameters.
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+ * Pipeline parameters.
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*
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- * To accomplish non-pipelined mode, we simply set the following
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- * variables to zero (or NULL, where appropriate).
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+ * To accomplish non-pipelined mode, we simply set the following
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+ * variables to zero (or NULL, where appropriate).
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*/
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/* Number of currently used stages */
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int nr_stages;
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@@ -385,9 +362,7 @@ typedef struct ide_tape_obj {
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/* protects the ide-tape queue */
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spinlock_t lock;
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- /*
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- * Measures average tape speed
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- */
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+ /* Measures average tape speed */
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unsigned long avg_time;
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int avg_size;
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int avg_speed;
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@@ -400,11 +375,9 @@ typedef struct ide_tape_obj {
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char write_prot;
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/*
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- * Limit the number of times a request can
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- * be postponed, to avoid an infinite postpone
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- * deadlock.
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+ * Limit the number of times a request can be postponed, to avoid an
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+ * infinite postpone deadlock.
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*/
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- /* request postpone count limit */
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int postpone_cnt;
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/*
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@@ -419,18 +392,14 @@ typedef struct ide_tape_obj {
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int tape_head;
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int last_tape_head;
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- /*
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- * Speed control at the tape buffers input/output
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- */
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+ /* Speed control at the tape buffers input/output */
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unsigned long insert_time;
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int insert_size;
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int insert_speed;
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int max_insert_speed;
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int measure_insert_time;
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- /*
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- * Speed regulation negative feedback loop
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- */
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+ /* Speed regulation negative feedback loop */
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int speed_control;
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int pipeline_head_speed;
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int controlled_pipeline_head_speed;
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@@ -477,9 +446,7 @@ static void ide_tape_put(struct ide_tape_obj *tape)
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mutex_unlock(&idetape_ref_mutex);
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}
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-/*
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- * Tape door status
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- */
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+/* Tape door status */
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#define DOOR_UNLOCKED 0
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#define DOOR_LOCKED 1
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#define DOOR_EXPLICITLY_LOCKED 2
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@@ -499,30 +466,23 @@ static void ide_tape_put(struct ide_tape_obj *tape)
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/* 0 = no tape is loaded, so we don't rewind after ejecting */
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#define IDETAPE_MEDIUM_PRESENT 9
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-/*
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- * Some defines for the READ BUFFER command
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- */
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+/* A define for the READ BUFFER command */
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#define IDETAPE_RETRIEVE_FAULTY_BLOCK 6
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-/*
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- * Some defines for the SPACE command
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- */
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+/* Some defines for the SPACE command */
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#define IDETAPE_SPACE_OVER_FILEMARK 1
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#define IDETAPE_SPACE_TO_EOD 3
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-/*
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- * Some defines for the LOAD UNLOAD command
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- */
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+/* Some defines for the LOAD UNLOAD command */
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#define IDETAPE_LU_LOAD_MASK 1
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#define IDETAPE_LU_RETENSION_MASK 2
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#define IDETAPE_LU_EOT_MASK 4
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/*
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- * Special requests for our block device strategy routine.
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+ * Special requests for our block device strategy routine.
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*
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- * In order to service a character device command, we add special
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- * requests to the tail of our block device request queue and wait
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- * for their completion.
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+ * In order to service a character device command, we add special requests to
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+ * the tail of our block device request queue and wait for their completion.
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*/
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enum {
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@@ -533,10 +493,7 @@ enum {
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REQ_IDETAPE_READ_BUFFER = (1 << 4),
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};
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-/*
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- * Error codes which are returned in rq->errors to the higher part
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- * of the driver.
|
|
|
- */
|
|
|
+/* Error codes returned in rq->errors to the higher part of the driver. */
|
|
|
#define IDETAPE_ERROR_GENERAL 101
|
|
|
#define IDETAPE_ERROR_FILEMARK 102
|
|
|
#define IDETAPE_ERROR_EOD 103
|
|
@@ -560,8 +517,8 @@ struct idetape_id_gcw {
|
|
|
#define IDETAPE_CAPABILITIES_PAGE 0x2a
|
|
|
|
|
|
/*
|
|
|
- * The variables below are used for the character device interface.
|
|
|
- * Additional state variables are defined in our ide_drive_t structure.
|
|
|
+ * The variables below are used for the character device interface. Additional
|
|
|
+ * state variables are defined in our ide_drive_t structure.
|
|
|
*/
|
|
|
static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
|
|
|
|
|
@@ -579,10 +536,6 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
|
|
|
return tape;
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * Function declarations
|
|
|
- *
|
|
|
- */
|
|
|
static int idetape_chrdev_release (struct inode *inode, struct file *filp);
|
|
|
static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
|
|
|
|
|
@@ -711,9 +664,6 @@ static struct request *idetape_next_rq_storage (ide_drive_t *drive)
|
|
|
return (&tape->rq_stack[tape->rq_stack_index++]);
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * idetape_init_pc initializes a packet command.
|
|
|
- */
|
|
|
static void idetape_init_pc (idetape_pc_t *pc)
|
|
|
{
|
|
|
memset(pc->c, 0, 12);
|
|
@@ -809,10 +759,7 @@ static void idetape_activate_next_stage(ide_drive_t *drive)
|
|
|
tape->next_stage = stage->next;
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * idetape_kfree_stage calls kfree to completely free a stage, along with
|
|
|
- * its related buffers.
|
|
|
- */
|
|
|
+/* Free a stage along with its related buffers completely. */
|
|
|
static void __idetape_kfree_stage (idetape_stage_t *stage)
|
|
|
{
|
|
|
struct idetape_bh *prev_bh, *bh = stage->bh;
|
|
@@ -840,8 +787,8 @@ static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_remove_stage_head removes tape->first_stage from the pipeline.
|
|
|
- * The caller should avoid race conditions.
|
|
|
+ * Remove tape->first_stage from the pipeline. The caller should avoid race
|
|
|
+ * conditions.
|
|
|
*/
|
|
|
static void idetape_remove_stage_head (ide_drive_t *drive)
|
|
|
{
|
|
@@ -899,8 +846,8 @@ static void idetape_abort_pipeline(ide_drive_t *drive,
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_end_request is used to finish servicing a request, and to
|
|
|
- * insert a pending pipeline request into the main device queue.
|
|
|
+ * Finish servicing a request and insert a pending pipeline request into the
|
|
|
+ * main device queue.
|
|
|
*/
|
|
|
static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
|
|
|
{
|
|
@@ -951,9 +898,7 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
|
|
|
if (tape->next_stage != NULL) {
|
|
|
idetape_activate_next_stage(drive);
|
|
|
|
|
|
- /*
|
|
|
- * Insert the next request into the request queue.
|
|
|
- */
|
|
|
+ /* Insert the next request into the request queue. */
|
|
|
(void)ide_do_drive_cmd(drive, tape->active_data_rq,
|
|
|
ide_end);
|
|
|
} else if (!error) {
|
|
@@ -1020,23 +965,19 @@ static void idetape_init_rq(struct request *rq, u8 cmd)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_queue_pc_head generates a new packet command request in front
|
|
|
- * of the request queue, before the current request, so that it will be
|
|
|
- * processed immediately, on the next pass through the driver.
|
|
|
- *
|
|
|
- * idetape_queue_pc_head is called from the request handling part of
|
|
|
- * the driver (the "bottom" part). Safe storage for the request should
|
|
|
- * be allocated with idetape_next_pc_storage and idetape_next_rq_storage
|
|
|
- * before calling idetape_queue_pc_head.
|
|
|
+ * Generate a new packet command request in front of the request queue, before
|
|
|
+ * the current request, so that it will be processed immediately, on the next
|
|
|
+ * pass through the driver. The function below is called from the request
|
|
|
+ * handling part of the driver (the "bottom" part). Safe storage for the request
|
|
|
+ * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
|
|
|
*
|
|
|
- * Memory for those requests is pre-allocated at initialization time, and
|
|
|
- * is limited to IDETAPE_PC_STACK requests. We assume that we have enough
|
|
|
- * space for the maximum possible number of inter-dependent packet commands.
|
|
|
+ * Memory for those requests is pre-allocated at initialization time, and is
|
|
|
+ * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
|
|
|
+ * the maximum possible number of inter-dependent packet commands.
|
|
|
*
|
|
|
- * The higher level of the driver - The ioctl handler and the character
|
|
|
- * device handling functions should queue request to the lower level part
|
|
|
- * and wait for their completion using idetape_queue_pc_tail or
|
|
|
- * idetape_queue_rw_tail.
|
|
|
+ * The higher level of the driver - The ioctl handler and the character device
|
|
|
+ * handling functions should queue request to the lower level part and wait for
|
|
|
+ * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
|
|
|
*/
|
|
|
static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
|
|
|
{
|
|
@@ -1069,9 +1010,8 @@ static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_postpone_request postpones the current request so that
|
|
|
- * ide.c will be able to service requests from another device on
|
|
|
- * the same hwgroup while we are polling for DSC.
|
|
|
+ * Postpone the current request so that ide.c will be able to service requests
|
|
|
+ * from another device on the same hwgroup while we are polling for DSC.
|
|
|
*/
|
|
|
static void idetape_postpone_request (ide_drive_t *drive)
|
|
|
{
|
|
@@ -1258,46 +1198,40 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * Packet Command Interface
|
|
|
+ * Packet Command Interface
|
|
|
*
|
|
|
- * The current Packet Command is available in tape->pc, and will not
|
|
|
- * change until we finish handling it. Each packet command is associated
|
|
|
- * with a callback function that will be called when the command is
|
|
|
- * finished.
|
|
|
+ * The current Packet Command is available in tape->pc, and will not change
|
|
|
+ * until we finish handling it. Each packet command is associated with a
|
|
|
+ * callback function that will be called when the command is finished.
|
|
|
*
|
|
|
- * The handling will be done in three stages:
|
|
|
+ * The handling will be done in three stages:
|
|
|
*
|
|
|
- * 1. idetape_issue_pc will send the packet command to the
|
|
|
- * drive, and will set the interrupt handler to idetape_pc_intr.
|
|
|
+ * 1. idetape_issue_pc will send the packet command to the drive, and will set
|
|
|
+ * the interrupt handler to idetape_pc_intr.
|
|
|
*
|
|
|
- * 2. On each interrupt, idetape_pc_intr will be called. This step
|
|
|
- * will be repeated until the device signals us that no more
|
|
|
- * interrupts will be issued.
|
|
|
+ * 2. On each interrupt, idetape_pc_intr will be called. This step will be
|
|
|
+ * repeated until the device signals us that no more interrupts will be issued.
|
|
|
*
|
|
|
- * 3. ATAPI Tape media access commands have immediate status with a
|
|
|
- * delayed process. In case of a successful initiation of a
|
|
|
- * media access packet command, the DSC bit will be set when the
|
|
|
- * actual execution of the command is finished.
|
|
|
- * Since the tape drive will not issue an interrupt, we have to
|
|
|
- * poll for this event. In this case, we define the request as
|
|
|
- * "low priority request" by setting rq_status to
|
|
|
- * IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and exit
|
|
|
- * the driver.
|
|
|
+ * 3. ATAPI Tape media access commands have immediate status with a delayed
|
|
|
+ * process. In case of a successful initiation of a media access packet command,
|
|
|
+ * the DSC bit will be set when the actual execution of the command is finished.
|
|
|
+ * Since the tape drive will not issue an interrupt, we have to poll for this
|
|
|
+ * event. In this case, we define the request as "low priority request" by
|
|
|
+ * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
|
|
|
+ * exit the driver.
|
|
|
*
|
|
|
- * ide.c will then give higher priority to requests which
|
|
|
- * originate from the other device, until will change rq_status
|
|
|
- * to RQ_ACTIVE.
|
|
|
+ * ide.c will then give higher priority to requests which originate from the
|
|
|
+ * other device, until will change rq_status to RQ_ACTIVE.
|
|
|
*
|
|
|
- * 4. When the packet command is finished, it will be checked for errors.
|
|
|
+ * 4. When the packet command is finished, it will be checked for errors.
|
|
|
*
|
|
|
- * 5. In case an error was found, we queue a request sense packet
|
|
|
- * command in front of the request queue and retry the operation
|
|
|
- * up to IDETAPE_MAX_PC_RETRIES times.
|
|
|
- *
|
|
|
- * 6. In case no error was found, or we decided to give up and not
|
|
|
- * to retry again, the callback function will be called and then
|
|
|
- * we will handle the next request.
|
|
|
+ * 5. In case an error was found, we queue a request sense packet command in
|
|
|
+ * front of the request queue and retry the operation up to
|
|
|
+ * IDETAPE_MAX_PC_RETRIES times.
|
|
|
*
|
|
|
+ * 6. In case no error was found, or we decided to give up and not to retry
|
|
|
+ * again, the callback function will be called and then we will handle the next
|
|
|
+ * request.
|
|
|
*/
|
|
|
static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
|
|
|
{
|
|
@@ -1363,9 +1297,9 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
|
|
|
if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
|
|
|
test_bit(PC_ABORT, &pc->flags)) {
|
|
|
/*
|
|
|
- * We will "abort" retrying a packet command in case
|
|
|
- * a legitimate error code was received (crossing a
|
|
|
- * filemark, or end of the media, for example).
|
|
|
+ * We will "abort" retrying a packet command in case legitimate
|
|
|
+ * error code was received (crossing a filemark, or end of the
|
|
|
+ * media, for example).
|
|
|
*/
|
|
|
if (!test_bit(PC_ABORT, &pc->flags)) {
|
|
|
if (!(pc->c[0] == TEST_UNIT_READY &&
|
|
@@ -1416,9 +1350,6 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * General packet command callback function.
|
|
|
- */
|
|
|
static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
|
|
|
{
|
|
|
idetape_tape_t *tape = drive->driver_data;
|
|
@@ -1429,15 +1360,14 @@ static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
|
|
|
return ide_stopped;
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * A mode sense command is used to "sense" tape parameters.
|
|
|
- */
|
|
|
+/* A mode sense command is used to "sense" tape parameters. */
|
|
|
static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
|
|
|
{
|
|
|
idetape_init_pc(pc);
|
|
|
pc->c[0] = MODE_SENSE;
|
|
|
if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
|
|
|
- pc->c[1] = 8; /* DBD = 1 - Don't return block descriptors */
|
|
|
+ /* DBD = 1 - Don't return block descriptors */
|
|
|
+ pc->c[1] = 8;
|
|
|
pc->c[2] = page_code;
|
|
|
/*
|
|
|
* Changed pc->c[3] to 0 (255 will at best return unused info).
|
|
@@ -1447,7 +1377,8 @@ static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
|
|
|
* and return an error when 255 is used.
|
|
|
*/
|
|
|
pc->c[3] = 0;
|
|
|
- pc->c[4] = 255; /* (We will just discard data in that case) */
|
|
|
+ /* We will just discard data in that case */
|
|
|
+ pc->c[4] = 255;
|
|
|
if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
|
|
|
pc->request_transfer = 12;
|
|
|
else if (page_code == IDETAPE_CAPABILITIES_PAGE)
|
|
@@ -1619,9 +1550,6 @@ static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, uns
|
|
|
set_bit(PC_DMA_RECOMMENDED, &pc->flags);
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * idetape_do_request is our request handling function.
|
|
|
- */
|
|
|
static ide_startstop_t idetape_do_request(ide_drive_t *drive,
|
|
|
struct request *rq, sector_t block)
|
|
|
{
|
|
@@ -1635,18 +1563,14 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
|
|
|
rq->sector, rq->nr_sectors, rq->current_nr_sectors);
|
|
|
|
|
|
if (!blk_special_request(rq)) {
|
|
|
- /*
|
|
|
- * We do not support buffer cache originated requests.
|
|
|
- */
|
|
|
+ /* We do not support buffer cache originated requests. */
|
|
|
printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
|
|
|
"request queue (%d)\n", drive->name, rq->cmd_type);
|
|
|
ide_end_request(drive, 0, 0);
|
|
|
return ide_stopped;
|
|
|
}
|
|
|
|
|
|
- /*
|
|
|
- * Retry a failed packet command
|
|
|
- */
|
|
|
+ /* Retry a failed packet command */
|
|
|
if (tape->failed_pc != NULL &&
|
|
|
tape->pc->c[0] == REQUEST_SENSE) {
|
|
|
return idetape_issue_pc(drive, tape->failed_pc);
|
|
@@ -1733,9 +1657,7 @@ out:
|
|
|
return idetape_issue_pc(drive, pc);
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * Pipeline related functions
|
|
|
- */
|
|
|
+/* Pipeline related functions */
|
|
|
static inline int idetape_pipeline_active (idetape_tape_t *tape)
|
|
|
{
|
|
|
int rc1, rc2;
|
|
@@ -1746,16 +1668,16 @@ static inline int idetape_pipeline_active (idetape_tape_t *tape)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_kmalloc_stage uses __get_free_page to allocate a pipeline
|
|
|
- * stage, along with all the necessary small buffers which together make
|
|
|
- * a buffer of size tape->stage_size (or a bit more). We attempt to
|
|
|
- * combine sequential pages as much as possible.
|
|
|
+ * The function below uses __get_free_page to allocate a pipeline stage, along
|
|
|
+ * with all the necessary small buffers which together make a buffer of size
|
|
|
+ * tape->stage_size (or a bit more). We attempt to combine sequential pages as
|
|
|
+ * much as possible.
|
|
|
*
|
|
|
- * Returns a pointer to the new allocated stage, or NULL if we
|
|
|
- * can't (or don't want to) allocate a stage.
|
|
|
+ * It returns a pointer to the new allocated stage, or NULL if we can't (or
|
|
|
+ * don't want to) allocate a stage.
|
|
|
*
|
|
|
- * Pipeline stages are optional and are used to increase performance.
|
|
|
- * If we can't allocate them, we'll manage without them.
|
|
|
+ * Pipeline stages are optional and are used to increase performance. If we
|
|
|
+ * can't allocate them, we'll manage without them.
|
|
|
*/
|
|
|
static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
|
|
|
{
|
|
@@ -1913,9 +1835,7 @@ static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage
|
|
|
idetape_init_merge_stage(tape);
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * idetape_add_stage_tail adds a new stage at the end of the pipeline.
|
|
|
- */
|
|
|
+/* Add a new stage at the end of the pipeline. */
|
|
|
static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
|
|
|
{
|
|
|
idetape_tape_t *tape = drive->driver_data;
|
|
@@ -1937,12 +1857,9 @@ static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
|
|
|
spin_unlock_irqrestore(&tape->lock, flags);
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * idetape_wait_for_request installs a completion in a pending request
|
|
|
- * and sleeps until it is serviced.
|
|
|
- *
|
|
|
- * The caller should ensure that the request will not be serviced
|
|
|
- * before we install the completion (usually by disabling interrupts).
|
|
|
+/* Install a completion in a pending request and sleep until it is serviced. The
|
|
|
+ * caller should ensure that the request will not be serviced before we install
|
|
|
+ * the completion (usually by disabling interrupts).
|
|
|
*/
|
|
|
static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
|
|
|
{
|
|
@@ -1996,12 +1913,8 @@ static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_create_write_filemark_cmd will:
|
|
|
- *
|
|
|
- * 1. Write a filemark if write_filemark=1.
|
|
|
- * 2. Flush the device buffers without writing a filemark
|
|
|
- * if write_filemark=0.
|
|
|
- *
|
|
|
+ * Write a filemark if write_filemark=1. Flush the device buffers without
|
|
|
+ * writing a filemark otherwise.
|
|
|
*/
|
|
|
static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
|
|
|
{
|
|
@@ -2020,24 +1933,17 @@ static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_queue_pc_tail is based on the following functions:
|
|
|
- *
|
|
|
- * ide_do_drive_cmd from ide.c
|
|
|
- * cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c
|
|
|
- *
|
|
|
- * We add a special packet command request to the tail of the request
|
|
|
- * queue, and wait for it to be serviced.
|
|
|
+ * We add a special packet command request to the tail of the request queue, and
|
|
|
+ * wait for it to be serviced. This is not to be called from within the request
|
|
|
+ * handling part of the driver! We allocate here data on the stack and it is
|
|
|
+ * valid until the request is finished. This is not the case for the bottom part
|
|
|
+ * of the driver, where we are always leaving the functions to wait for an
|
|
|
+ * interrupt or a timer event.
|
|
|
*
|
|
|
- * This is not to be called from within the request handling part
|
|
|
- * of the driver ! We allocate here data in the stack, and it is valid
|
|
|
- * until the request is finished. This is not the case for the bottom
|
|
|
- * part of the driver, where we are always leaving the functions to wait
|
|
|
- * for an interrupt or a timer event.
|
|
|
- *
|
|
|
- * From the bottom part of the driver, we should allocate safe memory
|
|
|
- * using idetape_next_pc_storage and idetape_next_rq_storage, and add
|
|
|
- * the request to the request list without waiting for it to be serviced !
|
|
|
- * In that case, we usually use idetape_queue_pc_head.
|
|
|
+ * From the bottom part of the driver, we should allocate safe memory using
|
|
|
+ * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
|
|
|
+ * to the request list without waiting for it to be serviced! In that case, we
|
|
|
+ * usually use idetape_queue_pc_head().
|
|
|
*/
|
|
|
static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
|
|
|
{
|
|
@@ -2065,9 +1971,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
|
|
|
idetape_pc_t pc;
|
|
|
int load_attempted = 0;
|
|
|
|
|
|
- /*
|
|
|
- * Wait for the tape to become ready
|
|
|
- */
|
|
|
+ /* Wait for the tape to become ready */
|
|
|
set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
|
|
|
timeout += jiffies;
|
|
|
while (time_before(jiffies, timeout)) {
|
|
@@ -2075,7 +1979,8 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
|
|
|
if (!__idetape_queue_pc_tail(drive, &pc))
|
|
|
return 0;
|
|
|
if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
|
|
|
- || (tape->asc == 0x3A)) { /* no media */
|
|
|
+ || (tape->asc == 0x3A)) {
|
|
|
+ /* no media */
|
|
|
if (load_attempted)
|
|
|
return -ENOMEDIUM;
|
|
|
idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
|
|
@@ -2203,13 +2108,10 @@ static int __idetape_discard_read_pipeline (ide_drive_t *drive)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_position_tape positions the tape to the requested block
|
|
|
- * using the LOCATE packet command. A READ POSITION command is then
|
|
|
- * issued to check where we are positioned.
|
|
|
- *
|
|
|
- * Like all higher level operations, we queue the commands at the tail
|
|
|
- * of the request queue and wait for their completion.
|
|
|
- *
|
|
|
+ * Position the tape to the requested block using the LOCATE packet command.
|
|
|
+ * A READ POSITION command is then issued to check where we are positioned. Like
|
|
|
+ * all higher level operations, we queue the commands at the tail of the request
|
|
|
+ * queue and wait for their completion.
|
|
|
*/
|
|
|
static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
|
|
|
{
|
|
@@ -2247,8 +2149,8 @@ static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_posit
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_queue_rw_tail generates a read/write request for the block
|
|
|
- * device interface and wait for it to be serviced.
|
|
|
+ * Generate a read/write request for the block device interface and wait for it
|
|
|
+ * to be serviced.
|
|
|
*/
|
|
|
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
|
|
|
{
|
|
@@ -2343,15 +2245,15 @@ static void idetape_wait_first_stage (ide_drive_t *drive)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_add_chrdev_write_request tries to add a character device
|
|
|
- * originated write request to our pipeline. In case we don't succeed,
|
|
|
- * we revert to non-pipelined operation mode for this request.
|
|
|
+ * Try to add a character device originated write request to our pipeline. In
|
|
|
+ * case we don't succeed, we revert to non-pipelined operation mode for this
|
|
|
+ * request. In order to accomplish that, we
|
|
|
*
|
|
|
- * 1. Try to allocate a new pipeline stage.
|
|
|
- * 2. If we can't, wait for more and more requests to be serviced
|
|
|
- * and try again each time.
|
|
|
- * 3. If we still can't allocate a stage, fallback to
|
|
|
- * non-pipelined operation mode for this request.
|
|
|
+ * 1. Try to allocate a new pipeline stage.
|
|
|
+ * 2. If we can't, wait for more and more requests to be serviced and try again
|
|
|
+ * each time.
|
|
|
+ * 3. If we still can't allocate a stage, fallback to non-pipelined operation
|
|
|
+ * mode for this request.
|
|
|
*/
|
|
|
static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
|
|
|
{
|
|
@@ -2362,10 +2264,7 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
|
|
|
|
|
|
debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
|
|
|
|
|
|
- /*
|
|
|
- * Attempt to allocate a new stage.
|
|
|
- * Pay special attention to possible race conditions.
|
|
|
- */
|
|
|
+ /* Attempt to allocate a new stage. Beware possible race conditions. */
|
|
|
while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
|
|
|
spin_lock_irqsave(&tape->lock, flags);
|
|
|
if (idetape_pipeline_active(tape)) {
|
|
@@ -2377,8 +2276,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
|
|
|
if (idetape_pipeline_active(tape))
|
|
|
continue;
|
|
|
/*
|
|
|
- * Linux is short on memory. Fallback to
|
|
|
- * non-pipelined operation mode for this request.
|
|
|
+ * The machine is short on memory. Fallback to non-
|
|
|
+ * pipelined operation mode for this request.
|
|
|
*/
|
|
|
return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
|
|
|
}
|
|
@@ -2395,11 +2294,11 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
|
|
|
idetape_calculate_speeds(drive);
|
|
|
|
|
|
/*
|
|
|
- * Estimate whether the tape has stopped writing by checking
|
|
|
- * if our write pipeline is currently empty. If we are not
|
|
|
- * writing anymore, wait for the pipeline to be full enough
|
|
|
- * (90%) before starting to service requests, so that we will
|
|
|
- * be able to keep up with the higher speeds of the tape.
|
|
|
+ * Estimate whether the tape has stopped writing by checking if our
|
|
|
+ * write pipeline is currently empty. If we are not writing anymore,
|
|
|
+ * wait for the pipeline to be almost completely full (90%) before
|
|
|
+ * starting to service requests, so that we will be able to keep up with
|
|
|
+ * the higher speeds of the tape.
|
|
|
*/
|
|
|
if (!idetape_pipeline_active(tape)) {
|
|
|
if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
|
|
@@ -2420,8 +2319,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_wait_for_pipeline will wait until all pending pipeline
|
|
|
- * requests are serviced. Typically called on device close.
|
|
|
+ * Wait until all pending pipeline requests are serviced. Typically called on
|
|
|
+ * device close.
|
|
|
*/
|
|
|
static void idetape_wait_for_pipeline (ide_drive_t *drive)
|
|
|
{
|
|
@@ -2490,10 +2389,10 @@ static void idetape_empty_write_pipeline (ide_drive_t *drive)
|
|
|
tape->chrdev_dir = IDETAPE_DIR_NONE;
|
|
|
|
|
|
/*
|
|
|
- * On the next backup, perform the feedback loop again.
|
|
|
- * (I don't want to keep sense information between backups,
|
|
|
- * as some systems are constantly on, and the system load
|
|
|
- * can be totally different on the next backup).
|
|
|
+ * On the next backup, perform the feedback loop again. (I don't want to
|
|
|
+ * keep sense information between backups, as some systems are
|
|
|
+ * constantly on, and the system load can be totally different on the
|
|
|
+ * next backup).
|
|
|
*/
|
|
|
tape->max_stages = tape->min_pipeline;
|
|
|
if (tape->first_stage != NULL ||
|
|
@@ -2545,11 +2444,10 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
|
|
|
tape->chrdev_dir = IDETAPE_DIR_READ;
|
|
|
|
|
|
/*
|
|
|
- * Issue a read 0 command to ensure that DSC handshake
|
|
|
- * is switched from completion mode to buffer available
|
|
|
- * mode.
|
|
|
- * No point in issuing this if DSC overlap isn't supported,
|
|
|
- * some drives (Seagate STT3401A) will return an error.
|
|
|
+ * Issue a read 0 command to ensure that DSC handshake is
|
|
|
+ * switched from completion mode to buffer available mode.
|
|
|
+ * No point in issuing this if DSC overlap isn't supported, some
|
|
|
+ * drives (Seagate STT3401A) will return an error.
|
|
|
*/
|
|
|
if (drive->dsc_overlap) {
|
|
|
bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
|
|
@@ -2590,9 +2488,8 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_add_chrdev_read_request is called from idetape_chrdev_read
|
|
|
- * to service a character device read request and add read-ahead
|
|
|
- * requests to our pipeline.
|
|
|
+ * Called from idetape_chrdev_read() to service a character device read request
|
|
|
+ * and add read-ahead requests to our pipeline.
|
|
|
*/
|
|
|
static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
|
|
|
{
|
|
@@ -2603,16 +2500,11 @@ static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
|
|
|
|
|
|
debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
|
|
|
|
|
|
- /*
|
|
|
- * If we are at a filemark, return a read length of 0
|
|
|
- */
|
|
|
+ /* If we are at a filemark, return a read length of 0 */
|
|
|
if (test_bit(IDETAPE_FILEMARK, &tape->flags))
|
|
|
return 0;
|
|
|
|
|
|
- /*
|
|
|
- * Wait for the next block to be available at the head
|
|
|
- * of the pipeline
|
|
|
- */
|
|
|
+ /* Wait for the next block to reach the head of the pipeline. */
|
|
|
idetape_init_read(drive, tape->max_stages);
|
|
|
if (tape->first_stage == NULL) {
|
|
|
if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
|
|
@@ -2651,7 +2543,7 @@ static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
|
|
|
idetape_tape_t *tape = drive->driver_data;
|
|
|
struct idetape_bh *bh;
|
|
|
int blocks;
|
|
|
-
|
|
|
+
|
|
|
while (bcount) {
|
|
|
unsigned int count;
|
|
|
|
|
@@ -2691,10 +2583,9 @@ static int idetape_pipeline_size (ide_drive_t *drive)
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * Rewinds the tape to the Beginning Of the current Partition (BOP).
|
|
|
- *
|
|
|
- * We currently support only one partition.
|
|
|
- */
|
|
|
+ * Rewinds the tape to the Beginning Of the current Partition (BOP). We
|
|
|
+ * currently support only one partition.
|
|
|
+ */
|
|
|
static int idetape_rewind_tape (ide_drive_t *drive)
|
|
|
{
|
|
|
int retval;
|
|
@@ -2716,13 +2607,7 @@ static int idetape_rewind_tape (ide_drive_t *drive)
|
|
|
return 0;
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * Our special ide-tape ioctl's.
|
|
|
- *
|
|
|
- * Currently there aren't any ioctl's.
|
|
|
- * mtio.h compatible commands should be issued to the character device
|
|
|
- * interface.
|
|
|
- */
|
|
|
+/* mtio.h compatible commands should be issued to the chrdev interface. */
|
|
|
static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
|
|
|
{
|
|
|
idetape_tape_t *tape = drive->driver_data;
|
|
@@ -2756,13 +2641,11 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned l
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * idetape_space_over_filemarks is now a bit more complicated than just
|
|
|
- * passing the command to the tape since we may have crossed some
|
|
|
- * filemarks during our pipelined read-ahead mode.
|
|
|
- *
|
|
|
- * As a minor side effect, the pipeline enables us to support MTFSFM when
|
|
|
- * the filemark is in our internal pipeline even if the tape doesn't
|
|
|
- * support spacing over filemarks in the reverse direction.
|
|
|
+ * The function below is now a bit more complicated than just passing the
|
|
|
+ * command to the tape since we may have crossed some filemarks during our
|
|
|
+ * pipelined read-ahead mode. As a minor side effect, the pipeline enables us to
|
|
|
+ * support MTFSFM when the filemark is in our internal pipeline even if the tape
|
|
|
+ * doesn't support spacing over filemarks in the reverse direction.
|
|
|
*/
|
|
|
static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
|
|
|
{
|
|
@@ -2781,10 +2664,7 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
|
|
|
}
|
|
|
|
|
|
if (tape->chrdev_dir == IDETAPE_DIR_READ) {
|
|
|
- /*
|
|
|
- * We have a read-ahead buffer. Scan it for crossed
|
|
|
- * filemarks.
|
|
|
- */
|
|
|
+ /* its a read-ahead buffer, scan it for crossed filemarks. */
|
|
|
tape->merge_stage_size = 0;
|
|
|
if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
|
|
|
++count;
|
|
@@ -2797,13 +2677,15 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
|
|
|
spin_lock_irqsave(&tape->lock, flags);
|
|
|
if (tape->first_stage == tape->active_stage) {
|
|
|
/*
|
|
|
- * We have reached the active stage in the read pipeline.
|
|
|
- * There is no point in allowing the drive to continue
|
|
|
- * reading any farther, so we stop the pipeline.
|
|
|
+ * We have reached the active stage in the read
|
|
|
+ * pipeline. There is no point in allowing the
|
|
|
+ * drive to continue reading any farther, so we
|
|
|
+ * stop the pipeline.
|
|
|
*
|
|
|
- * This section should be moved to a separate subroutine,
|
|
|
- * because a similar function is performed in
|
|
|
- * __idetape_discard_read_pipeline(), for example.
|
|
|
+ * This section should be moved to a separate
|
|
|
+ * subroutine because similar operations are
|
|
|
+ * done in __idetape_discard_read_pipeline(),
|
|
|
+ * for example.
|
|
|
*/
|
|
|
tape->next_stage = NULL;
|
|
|
spin_unlock_irqrestore(&tape->lock, flags);
|
|
@@ -2819,8 +2701,8 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
- * The filemark was not found in our internal pipeline.
|
|
|
- * Now we can issue the space command.
|
|
|
+ * The filemark was not found in our internal pipeline; now we can issue
|
|
|
+ * the space command.
|
|
|
*/
|
|
|
switch (mt_op) {
|
|
|
case MTFSF:
|
|
@@ -2843,21 +2725,19 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
|
|
|
|
|
|
|
|
|
/*
|
|
|
- * Our character device read / write functions.
|
|
|
+ * Our character device read / write functions.
|
|
|
*
|
|
|
- * The tape is optimized to maximize throughput when it is transferring
|
|
|
- * an integral number of the "continuous transfer limit", which is
|
|
|
- * a parameter of the specific tape (26 KB on my particular tape).
|
|
|
- * (32 kB for Onstream)
|
|
|
+ * The tape is optimized to maximize throughput when it is transferring an
|
|
|
+ * integral number of the "continuous transfer limit", which is a parameter of
|
|
|
+ * the specific tape (26kB on my particular tape, 32kB for Onstream).
|
|
|
*
|
|
|
- * As of version 1.3 of the driver, the character device provides an
|
|
|
- * abstract continuous view of the media - any mix of block sizes (even 1
|
|
|
- * byte) on the same backup/restore procedure is supported. The driver
|
|
|
- * will internally convert the requests to the recommended transfer unit,
|
|
|
- * so that an unmatch between the user's block size to the recommended
|
|
|
- * size will only result in a (slightly) increased driver overhead, but
|
|
|
- * will no longer hit performance.
|
|
|
- * This is not applicable to Onstream.
|
|
|
+ * As of version 1.3 of the driver, the character device provides an abstract
|
|
|
+ * continuous view of the media - any mix of block sizes (even 1 byte) on the
|
|
|
+ * same backup/restore procedure is supported. The driver will internally
|
|
|
+ * convert the requests to the recommended transfer unit, so that an unmatch
|
|
|
+ * between the user's block size to the recommended size will only result in a
|
|
|
+ * (slightly) increased driver overhead, but will no longer hit performance.
|
|
|
+ * This is not applicable to Onstream.
|
|
|
*/
|
|
|
static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
|
|
|
size_t count, loff_t *ppos)
|
|
@@ -2950,11 +2830,10 @@ static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
|
|
|
idetape_init_merge_stage(tape);
|
|
|
|
|
|
/*
|
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|
- * Issue a write 0 command to ensure that DSC handshake
|
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|
- * is switched from completion mode to buffer available
|
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|
- * mode.
|
|
|
- * No point in issuing this if DSC overlap isn't supported,
|
|
|
- * some drives (Seagate STT3401A) will return an error.
|
|
|
+ * Issue a write 0 command to ensure that DSC handshake is
|
|
|
+ * switched from completion mode to buffer available mode. No
|
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|
+ * point in issuing this if DSC overlap isn't supported, some
|
|
|
+ * drives (Seagate STT3401A) will return an error.
|
|
|
*/
|
|
|
if (drive->dsc_overlap) {
|
|
|
ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
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|
@@ -3045,9 +2924,7 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
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|
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|
debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
|
|
|
mt_op, mt_count);
|
|
|
- /*
|
|
|
- * Commands which need our pipelined read-ahead stages.
|
|
|
- */
|
|
|
+ /* Commands which need our pipelined read-ahead stages. */
|
|
|
switch (mt_op) {
|
|
|
case MTFSF:
|
|
|
case MTFSFM:
|
|
@@ -3235,9 +3112,6 @@ static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
|
|
|
tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7;
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * Our character device open function.
|
|
|
- */
|
|
|
static int idetape_chrdev_open (struct inode *inode, struct file *filp)
|
|
|
{
|
|
|
unsigned int minor = iminor(inode), i = minor & ~0xc0;
|
|
@@ -3304,9 +3178,7 @@ static int idetape_chrdev_open (struct inode *inode, struct file *filp)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
- /*
|
|
|
- * Lock the tape drive door so user can't eject.
|
|
|
- */
|
|
|
+ /* Lock the tape drive door so user can't eject. */
|
|
|
if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
|
|
|
if (idetape_create_prevent_cmd(drive, &pc, 1)) {
|
|
|
if (!idetape_queue_pc_tail(drive, &pc)) {
|
|
@@ -3341,9 +3213,6 @@ static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
|
|
|
idetape_flush_tape_buffers(drive);
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * Our character device release function.
|
|
|
- */
|
|
|
static int idetape_chrdev_release (struct inode *inode, struct file *filp)
|
|
|
{
|
|
|
struct ide_tape_obj *tape = ide_tape_f(filp);
|
|
@@ -3500,9 +3369,6 @@ static void idetape_add_settings (ide_drive_t *drive)
|
|
|
{
|
|
|
idetape_tape_t *tape = drive->driver_data;
|
|
|
|
|
|
-/*
|
|
|
- * drive setting name read/write data type min max mul_factor div_factor data pointer set function
|
|
|
- */
|
|
|
ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
|
|
|
1, 2, (u16 *)&tape->caps[16], NULL);
|
|
|
ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff, tape->stage_size / 1024, 1, &tape->min_pipeline, NULL);
|
|
@@ -3529,16 +3395,15 @@ static inline void idetape_add_settings(ide_drive_t *drive) { ; }
|
|
|
#endif
|
|
|
|
|
|
/*
|
|
|
- * ide_setup is called to:
|
|
|
+ * The function below is called to:
|
|
|
*
|
|
|
- * 1. Initialize our various state variables.
|
|
|
- * 2. Ask the tape for its capabilities.
|
|
|
- * 3. Allocate a buffer which will be used for data
|
|
|
- * transfer. The buffer size is chosen based on
|
|
|
- * the recommendation which we received in step (2).
|
|
|
+ * 1. Initialize our various state variables.
|
|
|
+ * 2. Ask the tape for its capabilities.
|
|
|
+ * 3. Allocate a buffer which will be used for data transfer. The buffer size
|
|
|
+ * is chosen based on the recommendation which we received in step 2.
|
|
|
*
|
|
|
- * Note that at this point ide.c already assigned us an irq, so that
|
|
|
- * we can queue requests here and wait for their completion.
|
|
|
+ * Note that at this point ide.c already assigned us an irq, so that we can
|
|
|
+ * queue requests here and wait for their completion.
|
|
|
*/
|
|
|
static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
|
|
|
{
|
|
@@ -3572,7 +3437,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
|
|
|
set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
|
|
|
|
|
|
tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
|
|
|
-
|
|
|
+
|
|
|
idetape_get_inquiry_results(drive);
|
|
|
idetape_get_mode_sense_results(drive);
|
|
|
ide_tape_get_bsize_from_bdesc(drive);
|
|
@@ -3595,9 +3460,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
|
|
|
|
|
|
tape->max_stages = speed * 1000 * 10 / tape->stage_size;
|
|
|
|
|
|
- /*
|
|
|
- * Limit memory use for pipeline to 10% of physical memory
|
|
|
- */
|
|
|
+ /* Limit memory use for pipeline to 10% of physical memory */
|
|
|
si_meminfo(&si);
|
|
|
if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
|
|
|
tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size);
|
|
@@ -3617,8 +3480,8 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
|
|
|
t = t1;
|
|
|
|
|
|
/*
|
|
|
- * Ensure that the number we got makes sense; limit
|
|
|
- * it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
|
|
|
+ * Ensure that the number we got makes sense; limit it within
|
|
|
+ * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
|
|
|
*/
|
|
|
tape->best_dsc_rw_freq = max_t(unsigned long,
|
|
|
min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
|
|
@@ -3706,9 +3569,7 @@ static ide_driver_t idetape_driver = {
|
|
|
#endif
|
|
|
};
|
|
|
|
|
|
-/*
|
|
|
- * Our character device supporting functions, passed to register_chrdev.
|
|
|
- */
|
|
|
+/* Our character device supporting functions, passed to register_chrdev. */
|
|
|
static const struct file_operations idetape_fops = {
|
|
|
.owner = THIS_MODULE,
|
|
|
.read = idetape_chrdev_read,
|