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From:   Logan Gunthorpe <logang@deltatee.com>
To:     linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-mm@kvack.org, iommu@lists.linux-foundation.org
Cc:     Stephen Bates <sbates@raithlin.com>,
        Christoph Hellwig <hch@lst.de>,
        Dan Williams <dan.j.williams@intel.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Don Dutile <ddutile@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Jakowski Andrzej <andrzej.jakowski@intel.com>,
        Minturn Dave B <dave.b.minturn@intel.com>,
        Jason Ekstrand <jason@jlekstrand.net>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Xiong Jianxin <jianxin.xiong@intel.com>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Ira Weiny <ira.weiny@intel.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Martin Oliveira <martin.oliveira@eideticom.com>,
        Chaitanya Kulkarni <ckulkarnilinux@gmail.com>,
        Logan Gunthorpe <logang@deltatee.com>
Date:   Thu, 16 Sep 2021 17:40:56 -0600
Message-Id: <20210916234100.122368-17-logang@deltatee.com>
In-Reply-To: <20210916234100.122368-1-logang@deltatee.com>
References: <20210916234100.122368-1-logang@deltatee.com>
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Subject: [PATCH v3 16/20] block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages()
Precedence: bulk

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