From 6e3c5052f9686192e178806e017b7377155f4bab Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Thu, 22 Jan 2026 18:16:41 +0100 Subject: [PATCH] smb: smbdirect: introduce smbdirect_socket.recv_io.credits.available The logic off managing recv credits by counting posted recv_io and granted credits is racy. That's because the peer might already consumed a credit, but between receiving the incoming recv at the hardware and processing the completion in the 'recv_done' functions we likely have a window where we grant credits, which don't really exist. So we better have a decicated counter for the available credits, which will be incremented when we posted new recv buffers and drained when we grant the credits to the peer. Fixes: 5fb9b459b368 ("smb: client: count the number of posted recv_io messages in order to calculated credits") Fixes: 89b021a72663 ("smb: server: manage recv credits by counting posted recv_io and granted credits") 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 --- fs/smb/common/smbdirect/smbdirect_socket.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/smb/common/smbdirect/smbdirect_socket.h b/fs/smb/common/smbdirect/smbdirect_socket.h index ee4c2726771a..403a8b2cd30e 100644 --- a/fs/smb/common/smbdirect/smbdirect_socket.h +++ b/fs/smb/common/smbdirect/smbdirect_socket.h @@ -239,6 +239,7 @@ struct smbdirect_socket { */ struct { u16 target; + atomic_t available; atomic_t count; } credits; @@ -387,6 +388,7 @@ static __always_inline void smbdirect_socket_init(struct smbdirect_socket *sc) INIT_WORK(&sc->recv_io.posted.refill_work, __smbdirect_socket_disabled_work); disable_work_sync(&sc->recv_io.posted.refill_work); + atomic_set(&sc->recv_io.credits.available, 0); atomic_set(&sc->recv_io.credits.count, 0); INIT_LIST_HEAD(&sc->recv_io.reassembly.list);