From: Paulo Alcantara pc@cjr.nz
commit 6988a619f5b79e4efadea6e19dcfe75fbcd350b5 upstream.
A customer has reported that several files in their multi-threaded app were left with size of 0 because most of the read(2) calls returned -EINTR and they assumed no bytes were read. Obviously, they could have fixed it by simply retrying on -EINTR.
We noticed that most of the -EINTR on read(2) were due to real-time signals sent by glibc to process wide credential changes (SIGRT_1), and its signal handler had been established with SA_RESTART, in which case those calls could have been automatically restarted by the kernel.
Let the kernel decide to whether or not restart the syscalls when there is a signal pending in __smb_send_rqst() by returning -ERESTARTSYS. If it can't, it will return -EINTR anyway.
Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz CC: Stable stable@vger.kernel.org Reviewed-by: Ronnie Sahlberg lsahlber@redhat.com Reviewed-by: Pavel Shilovsky pshilov@microsoft.com Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/cifs/transport.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -339,8 +339,8 @@ __smb_send_rqst(struct TCP_Server_Info * return -EAGAIN;
if (signal_pending(current)) { - cifs_dbg(FYI, "signal is pending before sending any data\n"); - return -EINTR; + cifs_dbg(FYI, "signal pending before send request\n"); + return -ERESTARTSYS; }
/* cork the socket */