From: Chuck Lever Date: Thu, 20 Dec 2007 14:54:42 -0500 NFS: Fix use of copy_to_user() in idmap_pipe_upcall 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 Signed-off-by: Trond Myklebust --- fs/nfs/idmap.c | 14 ++++++-------- 1 files changed, 6 insertions(+), 8 deletions(-) diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c index c56fc7d..d93e071 100644 --- a/fs/nfs/idmap.c +++ b/fs/nfs/idmap.c @@ -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;