NFS: Fix use of copy_to_user() in idmap_pipe_upcall (a661b77f) · Commits · 戴 / test

The idmap_pipe_upcall() function expects the copy_to_user() function to return a negative error value if the call fails, but copy_to_user() returns an unsigned long number of bytes that couldn't be copied. Signed-off-by:

Chuck Lever <chuck.lever@oracle.com> Signed-off-by:

Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/idmap.c

+6 −8

Original line number	Diff line number	Diff line
		@@ -358,17 +358,15 @@ idmap_pipe_upcall(struct file filp, struct rpc_pipe_msg msg,
		char __user *dst, size_t buflen)
		{
		char data = (char )msg->data + msg->copied;
		ssize_t mlen = msg->len - msg->copied;
		ssize_t left;

		if (mlen > buflen)
		mlen = buflen;
		size_t mlen = min(msg->len, buflen);
		unsigned long left;

		left = copy_to_user(dst, data, mlen);
		if (left < 0) {
		msg->errno = left;
		return left;
		if (left == mlen) {
		msg->errno = -EFAULT;
		return -EFAULT;
		}

		mlen -= left;
		msg->copied += mlen;
		msg->errno = 0;

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