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Commit d0ba1e49 authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

NVMe: Correct sg list setup in nvme_map_user_pages 



Our SG list was constructed to always fill the entire first page, even
if that was more than the length of the I/O.  This is probably harmless,
but some IOMMUs might do something bad.

Correcting the first call to sg_set_page() made it look a lot closer to
the sg_set_page() in the loop, so fold the first call to sg_set_page()
into the loop.

Reported-by: default avatarNisheeth Bhat <nisheeth.bhat@intel.com>
Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
parent 6413214c

drivers/block/nvme.c

+5 −5
Original line number Diff line number Diff line
@@ -996,11 +996,11 @@ static int nvme_map_user_pages(struct nvme_dev *dev, int write, 


	sg = kcalloc(count, sizeof(*sg), GFP_KERNEL);

	sg_init_table(sg, count);

	sg_set_page(&sg[0], pages[0], PAGE_SIZE - offset, offset);

	for (i = 0; i < count; i++) {

		sg_set_page(&sg[i], pages[i],

				min_t(int, length, PAGE_SIZE - offset), offset);

		length -= (PAGE_SIZE - offset);

	for (i = 1; i < count; i++) {

		sg_set_page(&sg[i], pages[i], min_t(int, length, PAGE_SIZE), 0);

		length -= PAGE_SIZE;

		offset = 0;

	}



	err = -ENOMEM;