[PATCH v3 1/4] fs/splice: introduce pages_to_pipe helper

[Mike Rapoport]

Signed-off-by: Mike Rapoport <r...@linux.vnet.ibm.com>
---
 fs/splice.c | 57 ++++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 36 insertions(+), 21 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 39e2dc0..7f1ffc5 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1185,6 +1185,36 @@ static long do_splice(struct file *in, loff_t __user 
*off_in,
        return -EINVAL;
 }
 
+static int pages_to_pipe(struct page **pages, struct pipe_inode_info *pipe,
+                        struct pipe_buffer *buf, size_t *total,
+                        ssize_t copied, size_t start)
+{
+       bool failed = false;
+       size_t len = 0;
+       int ret = 0;
+       int n;
+
+       for (n = 0; copied; n++, start = 0) {
+               int size = min_t(int, copied, PAGE_SIZE - start);
+               if (!failed) {
+                       buf->page = pages[n];
+                       buf->offset = start;
+                       buf->len = size;
+                       ret = add_to_pipe(pipe, buf);
+                       if (unlikely(ret < 0))
+                               failed = true;
+                       else
+                               len += ret;
+               } else {
+                       put_page(pages[n]);
+               }
+               copied -= size;
+       }
+
+       *total += len;
+       return failed ? ret : len;
+}
+
 static int iter_to_pipe(struct iov_iter *from,
                        struct pipe_inode_info *pipe,
                        unsigned flags)
@@ -1195,13 +1225,11 @@ static int iter_to_pipe(struct iov_iter *from,
        };
        size_t total = 0;
        int ret = 0;
-       bool failed = false;
 
-       while (iov_iter_count(from) && !failed) {
+       while (iov_iter_count(from)) {
                struct page *pages[16];
                ssize_t copied;
                size_t start;
-               int n;
 
                copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
                if (copied <= 0) {
@@ -1209,24 +1237,11 @@ static int iter_to_pipe(struct iov_iter *from,
                        break;
                }
 
-               for (n = 0; copied; n++, start = 0) {
-                       int size = min_t(int, copied, PAGE_SIZE - start);
-                       if (!failed) {
-                               buf.page = pages[n];
-                               buf.offset = start;
-                               buf.len = size;
-                               ret = add_to_pipe(pipe, &buf);
-                               if (unlikely(ret < 0)) {
-                                       failed = true;
-                               } else {
-                                       iov_iter_advance(from, ret);
-                                       total += ret;
-                               }
-                       } else {
-                               put_page(pages[n]);
-                       }
-                       copied -= size;
-               }
+               ret = pages_to_pipe(pages, pipe, &buf, &total, copied, start);
+               if (unlikely(ret < 0))
+                       break;
+
+               iov_iter_advance(from, ret);
        }
        return total ? total : ret;
 }
-- 
2.7.4