[PATCH v2] fs/ceph: use pipe_get_pages_alloc() for pipe

From: John Hubbard
Date: Mon Aug 24 2020 - 21:20:41 EST


This reduces, by one, the number of callers of iov_iter_get_pages().
That's helpful because these calls are being audited and converted over
to use iov_iter_pin_user_pages(), where applicable. And this one here is
already known by the caller to be only for ITER_PIPE, so let's just
simplify it now.

Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---

OK, here's a v2 that does EXPORT_SYMBOL_GPL, instead of EXPORT_SYMBOL,
that's the only change from v1. That should help give this patch a
clear bill of passage. :)

thanks,
John Hubbard
NVIDIA

fs/ceph/file.c | 3 +--
include/linux/uio.h | 3 ++-
lib/iov_iter.c | 6 +++---
3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index d51c3f2fdca0..d3d7dd957390 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -879,8 +879,7 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
more = len < iov_iter_count(to);

if (unlikely(iov_iter_is_pipe(to))) {
- ret = iov_iter_get_pages_alloc(to, &pages, len,
- &page_off);
+ ret = pipe_get_pages_alloc(to, &pages, len, &page_off);
if (ret <= 0) {
ceph_osdc_put_request(req);
ret = -ENOMEM;
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 3835a8a8e9ea..270a4dcf5453 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -226,7 +226,8 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
size_t maxsize, size_t *start);
int iov_iter_npages(const struct iov_iter *i, int maxpages);
-
+ssize_t pipe_get_pages_alloc(struct iov_iter *i, struct page ***pages,
+ size_t maxsize, size_t *start);
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags);

static inline size_t iov_iter_count(const struct iov_iter *i)
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 5e40786c8f12..6290998df480 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1355,9 +1355,8 @@ static struct page **get_pages_array(size_t n)
return kvmalloc_array(n, sizeof(struct page *), GFP_KERNEL);
}

-static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
- struct page ***pages, size_t maxsize,
- size_t *start)
+ssize_t pipe_get_pages_alloc(struct iov_iter *i, struct page ***pages,
+ size_t maxsize, size_t *start)
{
struct page **p;
unsigned int iter_head, npages;
@@ -1387,6 +1386,7 @@ static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
kvfree(p);
return n;
}
+EXPORT_SYMBOL_GPL(pipe_get_pages_alloc);

ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
struct page ***pages, size_t maxsize,
--
2.28.0