[PATCH v9 2/8] iov_iter: introduce iov_iter_get_pages_[alloc_]flags()

Logan Gunthorpe
2022-08-25T15:24:59Z

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 | 40 ++++++++++++++++++++++++++++++++++++----
2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 5896af36199c..76ba69edb8c5 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_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_pages2(struct iov_iter *i, struct page **pages,
size_t maxsize, unsigned maxpages, size_t *start);
+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);
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..dedb78f3c655 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;

@@ -1497,10 +1497,24 @@ ssize_t iov_iter_get_pages2(struct iov_iter *i,
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, 0);
}
EXPORT_SYMBOL(iov_iter_get_pages2);

+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)
+{
+ if (!maxpages)
+ return 0;
+ BUG_ON(!pages);
+
+ return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages,
+ start, gup_flags);
+}
+EXPORT_SYMBOL_GPL(iov_iter_get_pages_flags);
+
ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
struct page ***pages, size_t maxsize,
size_t *start)
@@ -1509,7 +1523,7 @@ ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,

*pages = NULL;

- len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start);
+ len = __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start, 0);
if (len <= 0) {
kvfree(*pages);
*pages = NULL;
@@ -1518,6 +1532,24 @@ ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
}
EXPORT_SYMBOL(iov_iter_get_pages_alloc2);

+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)
+{
+ ssize_t len;
+
+ *pages = NULL;
+
+ 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_flags);
+
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
struct iov_iter *i)
{
--
2.30.2