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iter_to_pipe(): switch to advancing variant of iov_iter_get_pages() 

... and untangle the cleanup on failure to add into pipe.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2022-06-09 11:07:52 -04:00
parent 480cb846c2
commit 7d690c157c
1 changed files with 24 additions and 23 deletions
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47
fs/splice.c
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@ -1158,39 +1158,40 @@ 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;
ssize_t left;
size_t start;
int n;
int i, n;
copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
if (copied <= 0) {
ret = copied;
left = iov_iter_get_pages2(from, pages, ~0UL, 16, &start);
if (left <= 0) {
ret = left;
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]);
n = DIV_ROUND_UP(left + start, PAGE_SIZE);
for (i = 0; i < n; i++) {
int size = min_t(int, left, PAGE_SIZE - start);
buf.page = pages[i];
buf.offset = start;
buf.len = size;
ret = add_to_pipe(pipe, &buf);
if (unlikely(ret < 0)) {
iov_iter_revert(from, left);
// this one got dropped by add_to_pipe()
while (++i < n)
put_page(pages[i]);
goto out;
}
copied -= size;
total += ret;
left -= size;
start = 0;
}
}
out:
return total ? total : ret;
}