new helper: iov_iter_npages()

counts the pages covered by iov_iter, up to given limit.
do_block_direct_io() and fuse_iter_npages() switched to
it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 14 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 7db564d18dc6..7026014717bc 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1310,7 +1310,7 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 
         while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
                 unsigned npages;
-                size_t start, end, frag_size;
+                size_t start;
                 unsigned n = req->max_pages - req->num_pages;
                 ssize_t ret = iov_iter_get_pages(ii,
                                         &req->pages[req->num_pages],
@@ -1344,19 +1344,7 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 
 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
 {
-        struct iov_iter ii = *ii_p;
-        int npages = 0;
-
-        while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
-                unsigned long user_addr = fuse_get_user_addr(&ii);
-                unsigned offset = user_addr & ~PAGE_MASK;
-                size_t frag_size = iov_iter_single_seg_count(&ii);
-
-                npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
-                iov_iter_advance(&ii, frag_size);
-        }
-
-        return min(npages, FUSE_MAX_PAGES_PER_REQ);
+        return iov_iter_npages(ii_p, FUSE_MAX_PAGES_PER_REQ);
 }
 
 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,