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Date: Fri, 6 Nov 2020 10:00:32 -0700
From: Logan Gunthorpe <logang@...tatee.com>
To: linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
linux-block@...r.kernel.org, linux-pci@...r.kernel.org,
linux-mm@...ck.org, iommu@...ts.linux-foundation.org
Cc: Stephen Bates <sbates@...thlin.com>,
Christoph Hellwig <hch@....de>,
Dan Williams <dan.j.williams@...el.com>,
Jason Gunthorpe <jgg@...pe.ca>,
Christian König <christian.koenig@....com>,
Ira Weiny <iweiny@...el.com>,
John Hubbard <jhubbard@...dia.com>,
Don Dutile <ddutile@...hat.com>,
Matthew Wilcox <willy@...radead.org>,
Daniel Vetter <daniel.vetter@...ll.ch>,
Logan Gunthorpe <logang@...tatee.com>
Subject: [RFC PATCH 11/15] iov_iter: Introduce iov_iter_get_pages_[alloc_]flags()
Add iov_iter_get_pages_flags() and iov_iter_get_pages_alloc_flags()
which take a flags argument that is passed to get_user_pages_fast().
This is so that FOLL_PCI_P2PDMA can be passed when appropriate.
Signed-off-by: Logan Gunthorpe <logang@...tatee.com>
---
include/linux/uio.h | 21 +++++++++++++++++----
lib/iov_iter.c | 25 ++++++++++++++-----------
2 files changed, 31 insertions(+), 15 deletions(-)
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 72d88566694e..694caa868c05 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -221,10 +221,23 @@ void iov_iter_bvec(struct iov_iter *i, unsigned int direction, const struct bio_
void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode_info *pipe,
size_t count);
void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
-ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
- size_t maxsize, unsigned maxpages, size_t *start);
-ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
- size_t maxsize, size_t *start);
+ssize_t iov_iter_get_pages_flags(struct iov_iter *i, struct page **pages,
+ size_t maxsize, unsigned maxpages, size_t *start,
+ unsigned int gup_flags);
+ssize_t iov_iter_get_pages_alloc_flags(struct iov_iter *i,
+ struct page ***pages, size_t maxsize, size_t *start,
+ unsigned int gup_flags);
+static inline ssize_t iov_iter_get_pages(struct iov_iter *i,
+ struct page **pages, size_t maxsize, unsigned maxpages,
+ size_t *start)
+{
+ return iov_iter_get_pages_flags(i, pages, maxsize, maxpages, start, 0);
+}
+static inline ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
+ struct page ***pages, size_t maxsize, size_t *start)
+{
+ return iov_iter_get_pages_alloc_flags(i, pages, maxsize, start, 0);
+}
int iov_iter_npages(const struct iov_iter *i, int maxpages);
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 1635111c5bd2..700effe0bb86 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1313,9 +1313,9 @@ static ssize_t pipe_get_pages(struct iov_iter *i,
return __pipe_get_pages(i, min(maxsize, capacity), pages, iter_head, start);
}
-ssize_t iov_iter_get_pages(struct iov_iter *i,
+ssize_t iov_iter_get_pages_flags(struct iov_iter *i,
struct page **pages, size_t maxsize, unsigned maxpages,
- size_t *start)
+ size_t *start, unsigned int gup_flags)
{
if (maxsize > i->count)
maxsize = i->count;
@@ -1325,6 +1325,9 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
if (unlikely(iov_iter_is_discard(i)))
return -EFAULT;
+ if (iov_iter_rw(i) != WRITE)
+ gup_flags |= FOLL_WRITE;
+
iterate_all_kinds(i, maxsize, v, ({
unsigned long addr = (unsigned long)v.iov_base;
size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
@@ -1335,9 +1338,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
len = maxpages * PAGE_SIZE;
addr &= ~(PAGE_SIZE - 1);
n = DIV_ROUND_UP(len, PAGE_SIZE);
- res = get_user_pages_fast(addr, n,
- iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0,
- pages);
+ res = get_user_pages_fast(addr, n, gup_flags, pages);
if (unlikely(res < 0))
return res;
return (res == n ? len : res * PAGE_SIZE) - *start;
@@ -1352,7 +1353,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
)
return 0;
}
-EXPORT_SYMBOL(iov_iter_get_pages);
+EXPORT_SYMBOL(iov_iter_get_pages_flags);
static struct page **get_pages_array(size_t n)
{
@@ -1392,9 +1393,9 @@ static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
return n;
}
-ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
+ssize_t iov_iter_get_pages_alloc_flags(struct iov_iter *i,
struct page ***pages, size_t maxsize,
- size_t *start)
+ size_t *start, unsigned int gup_flags)
{
struct page **p;
@@ -1406,6 +1407,9 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
if (unlikely(iov_iter_is_discard(i)))
return -EFAULT;
+ if (iov_iter_rw(i) != WRITE)
+ gup_flags |= FOLL_WRITE;
+
iterate_all_kinds(i, maxsize, v, ({
unsigned long addr = (unsigned long)v.iov_base;
size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
@@ -1417,8 +1421,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
p = get_pages_array(n);
if (!p)
return -ENOMEM;
- res = get_user_pages_fast(addr, n,
- iov_iter_rw(i) != WRITE ? FOLL_WRITE : 0, p);
+ res = get_user_pages_fast(addr, n, gup_flags, p);
if (unlikely(res < 0)) {
kvfree(p);
return res;
@@ -1439,7 +1442,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
)
return 0;
}
-EXPORT_SYMBOL(iov_iter_get_pages_alloc);
+EXPORT_SYMBOL(iov_iter_get_pages_alloc_flags);
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
struct iov_iter *i)
--
2.20.1
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