Commit 5e3e3f2e authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Jens Axboe
Browse files

block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages() 



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 O_DIRECT path in iomap based filesystems
and direct to block devices.

Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221021174116.7200-7-logang@deltatee.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1567b49d

block/bio.c

+7 −2
Original line number Diff line number Diff line
@@ -1197,6 +1197,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 
	unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;

	struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;

	struct page **pages = (struct page **)bv;

	unsigned int gup_flags = 0;

	ssize_t size, left;

	unsigned len, i = 0;

	size_t offset, trim;
@@ -1210,6 +1211,9 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 
	BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);

	pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);



	if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue))

		gup_flags |= FOLL_PCI_P2PDMA;



	/*

	 * Each segment in the iov is required to be a block size multiple.

	 * However, we may not be able to get the entire segment if it spans
@@ -1217,8 +1221,9 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 
	 * result to ensure the bio's total size is correct. The remainder of

	 * the iov data will be picked up in the next bio iteration.

	 */

	size = iov_iter_get_pages2(iter, pages, UINT_MAX - bio->bi_iter.bi_size,

				  nr_pages, &offset);

	size = iov_iter_get_pages(iter, pages,

				  UINT_MAX - bio->bi_iter.bi_size,

				  nr_pages, &offset, gup_flags);

	if (unlikely(size <= 0))

		return size ? size : -EFAULT;