Staging: dgnc: Remove unused sniff code

The output written by dgnc_sniff_nowait_nolock() is never used
anywhere since commit 35cf90459312f ("staging: dgnc: removes proc code")
deleted the code that used to copy it to user space.
dgnc_sniff_nowait_nolock() uses 'timeval' to create header timestamps for
the data dump.

32-bit systems using 'struct timeval' will break in the year 2038,
This patch removes dgnc_sniff_nowait_nolock() and all ch_sniff_* members
of struct channel_t defined in "dgnc_driver.h". It also removes their usage
from the driver files and hence y2038 issue is also resolved.

Signed-off-by: Somya Anand <somyaanand214@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgnc/dgnc_cls.c

@@ -918,8 +918,6 @@ static void cls_copy_data_from_uart_to_queue(struct channel_t *ch)
 		ch->ch_equeue[head] = linestatus & (UART_LSR_BI | UART_LSR_PE
 								 | UART_LSR_FE);
 		ch->ch_rqueue[head] = readb(&ch->ch_cls_uart->txrx);
-		dgnc_sniff_nowait_nolock(ch, "UART READ",
-						 ch->ch_rqueue + head, 1);
 
 		qleft--;
 
@@ -1086,8 +1084,6 @@ static void cls_copy_data_from_queue_to_uart(struct channel_t *ch)
 			ch->ch_tun.un_flags |= (UN_EMPTY);
 		}
 		writeb(ch->ch_wqueue[ch->ch_w_tail], &ch->ch_cls_uart->txrx);
-		dgnc_sniff_nowait_nolock(ch, "UART WRITE",
-					    ch->ch_wqueue + ch->ch_w_tail, 1);
 		ch->ch_w_tail++;
 		ch->ch_w_tail &= WQUEUEMASK;
 		ch->ch_txcount++;

drivers/staging/dgnc/dgnc_driver.h

@@ -123,8 +123,6 @@
 #define   _POSIX_VDISABLE '\0'
 #endif
 
-#define SNIFF_MAX	65536		/* Sniff buffer size (2^n) */
-#define SNIFF_MASK	(SNIFF_MAX - 1)	/* Sniff wrap mask */
 
 /*
  * All the possible states the driver can be while being loaded.
@@ -331,13 +329,6 @@ struct un_t {
 #define CH_FORCED_STOP  0x20000		/* Output is forcibly stopped	*/
 #define CH_FORCED_STOPI 0x40000		/* Input is forcibly stopped	*/
 
-/*
- * Definitions for ch_sniff_flags
- */
-#define SNIFF_OPEN	0x1
-#define SNIFF_WAIT_DATA	0x2
-#define SNIFF_WAIT_SPACE 0x4
-
 
 /* Our Read/Error/Write queue sizes */
 #define RQUEUEMASK	0x1FFF		/* 8 K - 1 */
@@ -431,11 +422,6 @@ struct channel_t {
 	struct proc_dir_entry *proc_entry_pointer;
 	struct dgnc_proc_entry *dgnc_channel_table;
 
-	uint ch_sniff_in;
-	uint ch_sniff_out;
-	char *ch_sniff_buf;		/* Sniff buffer for proc */
-	ulong ch_sniff_flags;		/* Channel flags		*/
-	wait_queue_head_t ch_sniff_wait;
 };
 
 /*

drivers/staging/dgnc/dgnc_neo.c

@@ -1217,7 +1217,6 @@ static void neo_copy_data_from_uart_to_queue(struct channel_t *ch)
 
 		/* Copy data from uart to the queue */
 		memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, n);
-		dgnc_sniff_nowait_nolock(ch, "UART READ", ch->ch_rqueue + head, n);
 
 		/*
 		 * Since RX_FIFO_DATA_ERROR was 0, we are guarenteed
@@ -1303,7 +1302,6 @@ static void neo_copy_data_from_uart_to_queue(struct channel_t *ch)
 
 		memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, 1);
 		ch->ch_equeue[head] = (unsigned char) linestatus;
-		dgnc_sniff_nowait_nolock(ch, "UART READ", ch->ch_rqueue + head, 1);
 
 		/* Ditch any remaining linestatus value. */
 		linestatus = 0;
@@ -1556,7 +1554,6 @@ static void neo_copy_data_from_queue_to_uart(struct channel_t *ch)
 		}
 
 		memcpy_toio(&ch->ch_neo_uart->txrxburst, ch->ch_wqueue + tail, s);
-		dgnc_sniff_nowait_nolock(ch, "UART WRITE", ch->ch_wqueue + tail, s);
 
 		/* Add and flip queue if needed */
 		tail = (tail + s) & WQUEUEMASK;

drivers/staging/dgnc/dgnc_tty.c

@@ -49,7 +49,6 @@
 #include <linux/delay.h>	/* For udelay */
 #include <linux/uaccess.h>	/* For copy_from_user/copy_to_user */
 #include <linux/pci.h>
-
 #include "dgnc_driver.h"
 #include "dgnc_tty.h"
 #include "dgnc_types.h"
@@ -374,7 +373,6 @@ int dgnc_tty_init(struct dgnc_board *brd)
 		init_waitqueue_head(&ch->ch_flags_wait);
 		init_waitqueue_head(&ch->ch_tun.un_flags_wait);
 		init_waitqueue_head(&ch->ch_pun.un_flags_wait);
-		init_waitqueue_head(&ch->ch_sniff_wait);
 
 		{
 			struct device *classp;
@@ -449,127 +447,6 @@ void dgnc_tty_uninit(struct dgnc_board *brd)
 
 #define TMPBUFLEN (1024)
 
-/*
- * dgnc_sniff - Dump data out to the "sniff" buffer if the
- * proc sniff file is opened...
- */
-void dgnc_sniff_nowait_nolock(struct channel_t *ch, unsigned char *text, unsigned char *buf, int len)
-{
-	struct timeval tv;
-	int n;
-	int r;
-	int nbuf;
-	int i;
-	int tmpbuflen;
-	char *tmpbuf;
-	char *p;
-	int too_much_data;
-
-	tmpbuf = kzalloc(TMPBUFLEN, GFP_ATOMIC);
-	if (!tmpbuf)
-		return;
-	p = tmpbuf;
-
-	/* Leave if sniff not open */
-	if (!(ch->ch_sniff_flags & SNIFF_OPEN))
-		goto exit;
-
-	do_gettimeofday(&tv);
-
-	/* Create our header for data dump */
-	p += sprintf(p, "<%ld %ld><%s><", tv.tv_sec, tv.tv_usec, text);
-	tmpbuflen = p - tmpbuf;
-
-	do {
-		too_much_data = 0;
-
-		for (i = 0; i < len && tmpbuflen < (TMPBUFLEN - 4); i++) {
-			p += sprintf(p, "%02x ", *buf);
-			buf++;
-			tmpbuflen = p - tmpbuf;
-		}
-
-		if (tmpbuflen < (TMPBUFLEN - 4)) {
-			if (i > 0)
-				p += sprintf(p - 1, "%s\n", ">");
-			else
-				p += sprintf(p, "%s\n", ">");
-		} else {
-			too_much_data = 1;
-			len -= i;
-		}
-
-		nbuf = strlen(tmpbuf);
-		p = tmpbuf;
-
-		/*
-		 *  Loop while data remains.
-		 */
-		while (nbuf > 0 && ch->ch_sniff_buf) {
-			/*
-			 *  Determine the amount of available space left in the
-			 *  buffer.  If there's none, wait until some appears.
-			 */
-			n = (ch->ch_sniff_out - ch->ch_sniff_in - 1) & SNIFF_MASK;
-
-			/*
-			 * If there is no space left to write to in our sniff buffer,
-			 * we have no choice but to drop the data.
-			 * We *cannot* sleep here waiting for space, because this
-			 * function was probably called by the interrupt/timer routines!
-			 */
-			if (n == 0)
-				goto exit;
-
-			/*
-			 * Copy as much data as will fit.
-			 */
-
-			if (n > nbuf)
-				n = nbuf;
-
-			r = SNIFF_MAX - ch->ch_sniff_in;
-
-			if (r <= n) {
-				memcpy(ch->ch_sniff_buf + ch->ch_sniff_in, p, r);
-
-				n -= r;
-				ch->ch_sniff_in = 0;
-				p += r;
-				nbuf -= r;
-			}
-
-			memcpy(ch->ch_sniff_buf + ch->ch_sniff_in, p, n);
-
-			ch->ch_sniff_in += n;
-			p += n;
-			nbuf -= n;
-
-			/*
-			 *  Wakeup any thread waiting for data
-			 */
-			if (ch->ch_sniff_flags & SNIFF_WAIT_DATA) {
-				ch->ch_sniff_flags &= ~SNIFF_WAIT_DATA;
-				wake_up_interruptible(&ch->ch_sniff_wait);
-			}
-		}
-
-		/*
-		 * If the user sent us too much data to push into our tmpbuf,
-		 * we need to keep looping around on all the data.
-		 */
-		if (too_much_data) {
-			p = tmpbuf;
-			tmpbuflen = 0;
-		}
-
-	} while (too_much_data);
-
-exit:
-	kfree(tmpbuf);
-}
-
-
 /*=======================================================================
  *
  *	dgnc_wmove - Write data to transmit queue.
@@ -784,8 +661,6 @@ void dgnc_input(struct channel_t *ch)
 			tty_insert_flip_string(tp->port, ch->ch_rqueue + tail, s);
 		}
 
-		dgnc_sniff_nowait_nolock(ch, "USER READ", ch->ch_rqueue + tail, s);
-
 		tail += s;
 		n -= s;
 		/* Flip queue if needed */
@@ -1981,7 +1856,6 @@ static int dgnc_tty_write(struct tty_struct *tty,
 	if (n >= remain) {
 		n -= remain;
 		memcpy(ch->ch_wqueue + head, buf, remain);
-		dgnc_sniff_nowait_nolock(ch, "USER WRITE", ch->ch_wqueue + head, remain);
 		head = 0;
 		buf += remain;
 	}
@@ -1992,7 +1866,6 @@ static int dgnc_tty_write(struct tty_struct *tty,
 		 */
 		remain = n;
 		memcpy(ch->ch_wqueue + head, buf, remain);
-		dgnc_sniff_nowait_nolock(ch, "USER WRITE", ch->ch_wqueue + head, remain);
 		head += remain;
 	}
 

drivers/staging/dgnc/dgnc_tty.h

@@ -37,6 +37,4 @@ void	dgnc_carrier(struct channel_t *ch);
 void	dgnc_wakeup_writes(struct channel_t *ch);
 void	dgnc_check_queue_flow_control(struct channel_t *ch);
 
-void	dgnc_sniff_nowait_nolock(struct channel_t *ch, unsigned char *text, unsigned char *buf, int nbuf);
-
 #endif