3.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ilya Dryomov <idryo...@gmail.com> commit e7a88e82fe380459b864e05b372638aeacb0f52d upstream. The contract between try_read() and try_write() is that when called each processes as much data as possible. When instructed by osd_client to skip a message, try_read() is violating this contract by returning after receiving and discarding a single message instead of checking for more. try_write() then gets a chance to write out more requests, generating more replies/skips for try_read() to handle, forcing the messenger into a starvation loop. Reported-by: Varada Kari <varada.k...@sandisk.com> Signed-off-by: Ilya Dryomov <idryo...@gmail.com> Tested-by: Varada Kari <varada.k...@sandisk.com> Reviewed-by: Alex Elder <el...@linaro.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- net/ceph/messenger.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2279,7 +2279,7 @@ static int read_partial_message(struct c con->in_base_pos = -front_len - middle_len - data_len - sizeof(m->footer); con->in_tag = CEPH_MSGR_TAG_READY; - return 0; + return 1; } else if ((s64)seq - (s64)con->in_seq > 1) { pr_err("read_partial_message bad seq %lld expected %lld\n", seq, con->in_seq + 1); @@ -2312,7 +2312,7 @@ static int read_partial_message(struct c sizeof(m->footer); con->in_tag = CEPH_MSGR_TAG_READY; con->in_seq++; - return 0; + return 1; } BUG_ON(!con->in_msg);