scatterlist: do not disable IRQs in sg_copy_buffer

Commit 50bed2e ("sg: disable interrupts inside sg_copy_buffer")
introduced disabling interrupts in sg_copy_buffer() since atomic uses of
miter required it due to use of kmap_atomic().

However, as commit 8290e2d ("scatterlist: atomic sg_mapping_iter()
no longer needs disabled IRQs") acknowledges disabling interrupts is no
longer needed for calls to kmap_atomic() and therefore unneeded for
miter ops either, so remove it from sg_copy_buffer().

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Gilad Ben-Yossef <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib/scatterlist.c

@@ -651,7 +651,6 @@ size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
 {
 	unsigned int offset = 0;
 	struct sg_mapping_iter miter;
-	unsigned long flags;
 	unsigned int sg_flags = SG_MITER_ATOMIC;
 
 	if (to_buffer)
@@ -664,8 +663,6 @@ size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
 	if (!sg_miter_skip(&miter, skip))
 		return false;
 
-	local_irq_save(flags);
-
 	while ((offset < buflen) && sg_miter_next(&miter)) {
 		unsigned int len;
 
@@ -681,7 +678,6 @@ size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
 
 	sg_miter_stop(&miter);
 
-	local_irq_restore(flags);
 	return offset;
 }
 EXPORT_SYMBOL(sg_copy_buffer);