sg: disable interrupts inside sg_copy_buffer

The callers of sg_copy_buffer must disable interrupts before calling it (since it uses kmap_atomic). Some callers use it on interrupt-disabled code but some need to take the trouble to disable interrupts just for this. No wonder they forget about it and we hit a bug like: http://bugzilla.kernel.org/show_bug.cgi?id=11529 James said that it might be better to disable interrupts inside the function rather than risk the callers getting it wrong. Signed-off-by: FUJITA Tomonori <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
ericholscher · Sep 11, 2008 · 50bed2e · 50bed2e
1 parent 2dc75d3
commit 50bed2e
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
@@ -422,9 +422,12 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
 {
 	unsigned int offset = 0;
 	struct sg_mapping_iter miter;
+	unsigned long flags;
 
 	sg_miter_start(&miter, sgl, nents, SG_MITER_ATOMIC);
 
+	local_irq_save(flags);
+
 	while (sg_miter_next(&miter) && offset < buflen) {
 		unsigned int len;
 
@@ -442,6 +445,7 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
 
 	sg_miter_stop(&miter);
 
+	local_irq_restore(flags);
 	return offset;
 }