[PATCH v11 7/9] block: set FOLL_PCI_P2PDMA in bio_map_user_iov()

Logan Gunthorpe
2022-10-21T17:41:37Z

When a bio's queue supports PCI P2PDMA, set FOLL_PCI_P2PDMA for
iov_iter_get_pages_flags(). This allows PCI P2PDMA pages to be
passed from userspace and enables the NVMe passthru requests to
use P2PDMA pages.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
---
block/blk-map.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index 34735626b00f..8750f82d7da4 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -267,6 +267,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
{
unsigned int max_sectors = queue_max_hw_sectors(rq->q);
unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
+ unsigned int gup_flags = 0;
struct bio *bio;
int ret;
int j;
@@ -278,6 +279,9 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
if (bio == NULL)
return -ENOMEM;

+ if (blk_queue_pci_p2pdma(rq->q))
+ gup_flags |= FOLL_PCI_P2PDMA;
+
while (iov_iter_count(iter)) {
struct page **pages, *stack_pages[UIO_FASTIOV];
ssize_t bytes;
@@ -286,11 +290,11 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,

if (nr_vecs <= ARRAY_SIZE(stack_pages)) {
pages = stack_pages;
- bytes = iov_iter_get_pages2(iter, pages, LONG_MAX,
- nr_vecs, &offs);
+ bytes = iov_iter_get_pages(iter, pages, LONG_MAX,
+ nr_vecs, &offs, gup_flags);
} else {
- bytes = iov_iter_get_pages_alloc2(iter, &pages,
- LONG_MAX, &offs);
+ bytes = iov_iter_get_pages_alloc(iter, &pages,
+ LONG_MAX, &offs, gup_flags);
}
if (unlikely(bytes <= 0)) {
ret = bytes ? bytes : -EFAULT;
--
2.30.2