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s390/qdio: for_each macro correctness

I observed that there are for_each macros that do an extra memory access
beyond the defined area.
Normally this does not cause problems.
But, this can cause exceptions. For example: if the area is allocated at
the end of a page and the next page is not accessible.

For correctness, I suggest changing the arguments of the 'for loop' like
others 'for_each' do in the kernel.

Signed-off-by: Jose Alonso <joalonsof@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Jose Alonso 11 years ago
parent
commit
dbb0dd021d
1 changed files with 6 additions and 8 deletions
  1. 6 8
      drivers/s390/cio/qdio.h

+ 6 - 8
drivers/s390/cio/qdio.h

@@ -359,14 +359,12 @@ static inline int multicast_outbound(struct qdio_q *q)
 #define need_siga_sync_out_after_pci(q)	\
 #define need_siga_sync_out_after_pci(q)	\
 	(unlikely(q->irq_ptr->siga_flag.sync_out_after_pci))
 	(unlikely(q->irq_ptr->siga_flag.sync_out_after_pci))
 
 
-#define for_each_input_queue(irq_ptr, q, i)	\
-	for (i = 0, q = irq_ptr->input_qs[0];	\
-		i < irq_ptr->nr_input_qs;	\
-		q = irq_ptr->input_qs[++i])
-#define for_each_output_queue(irq_ptr, q, i)	\
-	for (i = 0, q = irq_ptr->output_qs[0];	\
-		i < irq_ptr->nr_output_qs;	\
-		q = irq_ptr->output_qs[++i])
+#define for_each_input_queue(irq_ptr, q, i)		\
+	for (i = 0; i < irq_ptr->nr_input_qs &&		\
+		({ q = irq_ptr->input_qs[i]; 1; }); i++)
+#define for_each_output_queue(irq_ptr, q, i)		\
+	for (i = 0; i < irq_ptr->nr_output_qs &&	\
+		({ q = irq_ptr->output_qs[i]; 1; }); i++)
 
 
 #define prev_buf(bufnr)	\
 #define prev_buf(bufnr)	\
 	((bufnr + QDIO_MAX_BUFFERS_MASK) & QDIO_MAX_BUFFERS_MASK)
 	((bufnr + QDIO_MAX_BUFFERS_MASK) & QDIO_MAX_BUFFERS_MASK)