From d0ba1e497bca83a3d353eb47c9658afc54d83228 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 13 Sep 2011 17:01:39 -0400 Subject: [PATCH] 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: Nisheeth Bhat Signed-off-by: Matthew Wilcox --- drivers/block/nvme.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c index 0956e1241520..5843409cac6d 100644 --- a/drivers/block/nvme.c +++ b/drivers/block/nvme.c @@ -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); - 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; + 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); + offset = 0; } err = -ENOMEM;