[PATCH v4 20/23] block: set FOLL_PCI_P2PDMA in bio_map_user_iov()

From: Logan Gunthorpe
Date: Wed Nov 17 2021 - 16:54:47 EST


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@xxxxxxxxxxxx>
---
block/blk-map.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index 4526adde0156..7508448e290c 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -234,6 +234,7 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
gfp_t gfp_mask)
{
unsigned int max_sectors = queue_max_hw_sectors(rq->q);
+ unsigned int flags = 0;
struct bio *bio;
int ret;
int j;
@@ -246,13 +247,17 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
return -ENOMEM;
bio->bi_opf |= req_op(rq);

+ if (blk_queue_pci_p2pdma(rq->q))
+ flags |= FOLL_PCI_P2PDMA;
+
while (iov_iter_count(iter)) {
struct page **pages;
ssize_t bytes;
size_t offs, added = 0;
int npages;

- bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs);
+ bytes = iov_iter_get_pages_alloc_flags(iter, &pages, LONG_MAX,
+ &offs, flags);
if (unlikely(bytes <= 0)) {
ret = bytes ? bytes : -EFAULT;
goto out_unmap;
--
2.30.2