[PATCH v3 16/20] block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages()
From: Logan Gunthorpe <logang@deltatee.com>
Date: 2021-09-16 23:41:36
Also in:
linux-iommu, linux-mm, linux-nvme, linux-pci, lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
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: Logan Gunthorpe <logang@deltatee.com> --- block/bio.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/block/bio.c b/block/bio.c
index 5df3dd282e40..2436e83fe3b4 100644
--- a/block/bio.c
+++ b/block/bio.c@@ -1088,6 +1088,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; struct page **pages = (struct page **)bv; bool same_page = false; + unsigned int flags = 0; ssize_t size, left; unsigned len, i; size_t offset;
@@ -1100,7 +1101,12 @@ 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); - size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); + if (bio->bi_bdev && bio->bi_bdev->bd_disk && + blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue)) + flags |= FOLL_PCI_P2PDMA; + + size = iov_iter_get_pages_flags(iter, pages, LONG_MAX, nr_pages, + &offset, flags); if (unlikely(size <= 0)) return size ? size : -EFAULT;
--
2.30.2