From 88cf40f7b5fb45463d444f76028b7250f129b15e Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Thu, 22 Jan 2026 18:16:42 +0100 Subject: [PATCH] smb: smbdirect: introduce smbdirect_socket.send_io.bcredits.* commit 8e94268b21c8235d430ce1aa6dc0b15952744b9b upstream. It turns out that our code will corrupt the stream of reassabled data transfer messages when we trigger an immendiate (empty) send. In order to fix this we'll have a single 'batch' credit per connection. And code getting that credit is free to use as much messages until remaining_length reaches 0, then the batch credit it given back and the next logical send can happen. Cc: # 6.18.x Cc: Steve French Cc: Tom Talpey Cc: Long Li Cc: Namjae Jeon Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Signed-off-by: Stefan Metzmacher Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/common/smbdirect/smbdirect_socket.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/smb/common/smbdirect/smbdirect_socket.h b/fs/smb/common/smbdirect/smbdirect_socket.h index e505dc77b70e..ca22b7c2d3a7 100644 --- a/fs/smb/common/smbdirect/smbdirect_socket.h +++ b/fs/smb/common/smbdirect/smbdirect_socket.h @@ -154,6 +154,17 @@ struct smbdirect_socket { mempool_t *pool; } mem; + /* + * This is a coordination for smbdirect_send_batch. + * + * There's only one possible credit, which means + * only one instance is running at a time. + */ + struct { + atomic_t count; + wait_queue_head_t wait_queue; + } bcredits; + /* * The local credit state for ib_post_send() */ @@ -359,6 +370,9 @@ static __always_inline void smbdirect_socket_init(struct smbdirect_socket *sc) INIT_DELAYED_WORK(&sc->idle.timer_work, __smbdirect_socket_disabled_work); disable_delayed_work_sync(&sc->idle.timer_work); + atomic_set(&sc->send_io.bcredits.count, 0); + init_waitqueue_head(&sc->send_io.bcredits.wait_queue); + atomic_set(&sc->send_io.lcredits.count, 0); init_waitqueue_head(&sc->send_io.lcredits.wait_queue); @@ -473,6 +487,8 @@ struct smbdirect_send_batch { */ bool need_invalidate_rkey; u32 remote_key; + + int credit; }; struct smbdirect_recv_io {