[PATCH v5 1/4] fs/splice: introduce pages_to_pipe helper

Mike Rapoport
2018-01-09T06:31:14Z

Signed-off-by: Mike Rapoport <rppt@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 39e2dc01ac12..7f1ffc50ff1d 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