[PATCH v10 2/8] iov_iter: introduce iov_iter_get_pages_[alloc_]flags()

Logan Gunthorpe
2022-09-22T16:41:06Z

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@deltatee.com>
---
include/linux/uio.h | 6 ++++++
lib/iov_iter.c | 32 ++++++++++++++++++++++++--------
2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 5896af36199c..5d976d01ccb9 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -247,8 +247,14 @@ void iov_iter_pipe(struct iov_iter *i, unsigned int direction, struct pipe_inode
void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count);
void iov_iter_xarray(struct iov_iter *i, unsigned int direction, struct xarray *xarray,
loff_t start, size_t count);
+ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
+ size_t maxsize, unsigned maxpages, size_t *start,
+ unsigned gup_flags);
ssize_t iov_iter_get_pages2(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,
+ unsigned gup_flags);
ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages,
size_t maxsize, size_t *start);
int iov_iter_npages(const struct iov_iter *i, int maxpages);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 4b7fce72e3e5..8f089d661a41 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1427,7 +1427,8 @@ 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 maxpages, size_t *start,
+ unsigned int gup_flags)
{
unsigned int n;

@@ -1439,7 +1440,6 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
maxsize = MAX_RW_COUNT;

if (likely(user_backed_iter(i))) {
- unsigned int gup_flags = 0;
unsigned long addr;
int res;

@@ -1489,33 +1489,49 @@ static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i,
return -EFAULT;
}

-ssize_t iov_iter_get_pages2(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)
+ size_t *start, unsigned gup_flags)
{
if (!maxpages)
return 0;
BUG_ON(!pages);

- return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start);
+ return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
+ start, gup_flags);
+}
+EXPORT_SYMBOL_GPL(iov_iter_get_pages);
+
+ssize_t iov_iter_get_pages2(struct iov_iter *i, struct page **pages,
+ size_t maxsize, unsigned maxpages, size_t *start)
+{
+ return iov_iter_get_pages(i, pages, maxsize, maxpages, start, 0);
}
EXPORT_SYMBOL(iov_iter_get_pages2);

-ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
+ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
- size_t *start)
+ size_t *start, unsigned gup_flags)
{
ssize_t len;

*pages = NULL;

- len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
+ len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start,
+ gup_flags);
if (len <= 0) {
kvfree(*pages);
*pages = NULL;
}
return len;
}
+EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc);
+
+ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
+ struct page ***pages, size_t maxsize, size_t *start)
+{
+ return iov_iter_get_pages_alloc(i, pages, maxsize, start, 0);
+}
EXPORT_SYMBOL(iov_iter_get_pages_alloc2);

size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
--
2.30.2