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iov_iter: Define flags to qualify page extraction.

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Define flags to qualify page extraction to pass into iov_iter_*_pages*()
rather than passing in FOLL_* flags.

For now only a flag to allow peer-to-peer DMA is supported.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Logan Gunthorpe <logang@deltatee.com>
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
David Howells
2023-01-19 12:47:23 +00:00
committed by Steve French
parent 33b3b04154
commit f62e52d127
4 changed files with 23 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
lib/iov_iter.c
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@@ -1426,9 +1426,9 @@ static struct page *first_bvec_segment(const struct iov_iter *i,
static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
unsigned int maxpages, size_t *start,
unsigned int gup_flags)
iov_iter_extraction_t extraction_flags)
{
unsigned int n;
unsigned int n, gup_flags = 0;
if (maxsize > i->count)
maxsize = i->count;
@@ -1436,6 +1436,8 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
return 0;
if (maxsize > MAX_RW_COUNT)
maxsize = MAX_RW_COUNT;
if (extraction_flags & ITER_ALLOW_P2PDMA)
gup_flags |= FOLL_PCI_P2PDMA;
if (likely(user_backed_iter(i))) {
unsigned long addr;
@@ -1489,14 +1491,14 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
ssize_t iov_iter_get_pages(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
size_t *start, unsigned gup_flags)
size_t *start, iov_iter_extraction_t extraction_flags)
{
if (!maxpages)
return 0;
BUG_ON(!pages);
return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
start, gup_flags);
start, extraction_flags);
}
EXPORT_SYMBOL_GPL(iov_iter_get_pages);
@@ -1509,14 +1511,14 @@ EXPORT_SYMBOL(iov_iter_get_pages2);
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start, unsigned gup_flags)
size_t *start, iov_iter_extraction_t extraction_flags)
{
ssize_t len;
*pages = NULL;
len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start,
gup_flags);
extraction_flags);
if (len <= 0) {
kvfree(*pages);
*pages = NULL;