vfs: fix vmplice_to_user() (b6dd6f47) · Commits · 戴 / test

Commit "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:

Miklos Szeredi <mszeredi@suse.cz> Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

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);

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