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Commit b6dd6f47 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Al Viro
Browse files

vfs: fix vmplice_to_user() 



Commit 6130f531 "switch vmsplice_to_user() to copy_page_to_iter()" in
v3.15-rc1 broke vmsplice(2).

This patch fixes two bugs:

 - count is not initialized to a proper value, which resulted in no data
   being copied

 - if rw_copy_check_uvector() returns negative then the iov might be leaked.

Tested OK.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c7208164

fs/splice.c

+4 −2
Original line number Diff line number Diff line
@@ -1537,7 +1537,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, 
	struct iovec iovstack[UIO_FASTIOV];

	struct iovec *iov = iovstack;

	struct iov_iter iter;

	ssize_t count = 0;

	ssize_t count;



	pipe = get_pipe_info(file);

	if (!pipe)
@@ -1546,8 +1546,9 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, 
	ret = rw_copy_check_uvector(READ, uiov, nr_segs,

				    ARRAY_SIZE(iovstack), iovstack, &iov);

	if (ret <= 0)

		return ret;

		goto out;



	count = ret;

	iov_iter_init(&iter, iov, nr_segs, count, 0);



	sd.len = 0;
@@ -1560,6 +1561,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov, 
	ret = __splice_from_pipe(pipe, &sd, pipe_to_user);

	pipe_unlock(pipe);



out:

	if (iov != iovstack)

		kfree(iov);