FAILED: patch "[PATCH] smb: server: make use of rdma_destroy_qp()" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 0c2b53997e8f5e2ec9e0fbd17ac0436466b65488
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025071408-overarch-ashes-8fbd@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 0c2b53997e8f5e2ec9e0fbd17ac0436466b65488 Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <[email protected]>
Date: Wed, 2 Jul 2025 09:18:05 +0200
Subject: [PATCH] smb: server: make use of rdma_destroy_qp()

The qp is created by rdma_create_qp() as t->cm_id->qp and t->qp is just a shortcut.

rdma_destroy_qp() also calls ib_destroy_qp(cm_id->qp) internally, but it is protected by a mutex, clears the cm_id and also calls trace_cm_qp_destroy().

This should make the tracing more useful as both rdma_create_qp() and rdma_destroy_qp() are traces and it makes the code look more sane as functions from the same layer are used for the specific qp object.

trace-cmd stream -e rdma_cma:cm_qp_create -e rdma_cma:cm_qp_destroy shows this now while doing a mount and unmount from a client:

<...>-80 [002] 378.514182: cm_qp_create: cm.id=1 src=172.31.9.167:5445 dst=172.31.9.166:37113 tos=0 pd.id=0 qp_type=RC send_wr=867 recv_wr=255 qp_num=1 rc=0
<...>-6283 [001] 381.686172: cm_qp_destroy: cm.id=1 src=172.31.9.167:5445 dst=172.31.9.166:37113 tos=0 qp_num=1

Before we only saw the first line.

index 64a428a06ace..c6cbe0d56e32 100644
@@ -433,7 +433,8 @@ static void free_transport(struct smb_direct_transport *t)
 	if (t->qp) {
 		ib_drain_qp(t->qp);
 		ib_mr_pool_destroy(t->qp, &t->qp->rdma_mrs);
-		ib_destroy_qp(t->qp);
+		t->qp = NULL;
+		rdma_destroy_qp(t->cm_id);
 	}
 
 	ksmbd_debug(RDMA, "drain the reassembly queue\n");

@@ -1940,8 +1941,8 @@ static int smb_direct_create_qpair(struct smb_direct_transport *t,
 	return 0;
 err:
 	if (t->qp) {
-		ib_destroy_qp(t->qp);
 		t->qp = NULL;
+		rdma_destroy_qp(t->cm_id);
 	}
 	if (t->recv_cq) {
 		ib_destroy_cq(t->recv_cq);