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FAILED: Patch "smb: smbdirect: introduce smbdirect_socket.send_io.bcredits.*" failed to apply to 6.6-stable tree

PATCH Sasha Levin 1 participant 1 message Mar 1

Subsystems (3)
Stable branch SMB client (CIFS) Kernel SMB3 server (ksmbd)
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Sasha Levin

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The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From 8e94268b21c8235d430ce1aa6dc0b15952744b9b Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <[email protected]>
Date: Thu, 22 Jan 2026 18:16:42 +0100
Subject: [PATCH] smb: smbdirect: introduce smbdirect_socket.send_io.bcredits.*

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 <[email protected]> # 6.18.x
Cc Steve French <[email protected]>
Cc Tom Talpey <[email protected]>
Cc Long Li <[email protected]>
Cc Namjae Jeon <[email protected]>
Cc [email protected]
Cc [email protected]
Signed-off-by Stefan Metzmacher <[email protected]>
Acked-by Namjae Jeon <[email protected]>
Signed-off-by Steve French <[email protected]>
---
 fs/smb/common/smbdirect/smbdirect_socket.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
fs/smb/common/smbdirect/smbdirect_socket.h +16 -0
index 403a8b2cd30e4..95265192bb01b 100644
@@ -162,6 +162,17 @@ 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()
 		 */

@@ -371,6 +382,9 @@ 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);
 

@@ -485,6 +499,8 @@ struct smbdirect_send_batch {
 	 */
 	bool need_invalidate_rkey;
 	u32 remote_key;
+
+	int credit;
 };
 
 struct smbdirect_recv_io {
Signature · 1 line
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