Patch "9p/rdma: unmap receive dma buffer in rdma_request()/post_recv()" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    9p/rdma: unmap receive dma buffer in rdma_request()/post_recv()

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     9p-rdma-unmap-receive-dma-buffer-in-rdma_request-pos.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit dd692e598ed71a9696a7d289dd69ce8e4a86b0f6
Author: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
Date:   Wed Jan 4 10:04:24 2023 +0800

    9p/rdma: unmap receive dma buffer in rdma_request()/post_recv()
    
    [ Upstream commit 74a25e6e916cb57dab4267a96fbe8864ed21abdb ]
    
    When down_interruptible() or ib_post_send() failed in rdma_request(),
    receive dma buffer is not unmapped. Add unmap action to error path.
    Also if ib_post_recv() failed in post_recv(), dma buffer is not unmapped.
    Add unmap action to error path.
    
    Link: https://lkml.kernel.org/r/20230104020424.611926-1-shaozhengchao@xxxxxxxxxx
    Fixes: fc79d4b104f0 ("9p: rdma: RDMA Transport Support for 9P")
    Signed-off-by: Zhengchao Shao <shaozhengchao@xxxxxxxxxx>
    Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxx>
    Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
    Signed-off-by: Eric Van Hensbergen <ericvh@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index b21c3c2098159..c00e965c082bf 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -385,6 +385,7 @@ post_recv(struct p9_client *client, struct p9_rdma_context *c)
 	struct p9_trans_rdma *rdma = client->trans;
 	struct ib_recv_wr wr;
 	struct ib_sge sge;
+	int ret;
 
 	c->busa = ib_dma_map_single(rdma->cm_id->device,
 				    c->rc.sdata, client->msize,
@@ -402,7 +403,12 @@ post_recv(struct p9_client *client, struct p9_rdma_context *c)
 	wr.wr_cqe = &c->cqe;
 	wr.sg_list = &sge;
 	wr.num_sge = 1;
-	return ib_post_recv(rdma->qp, &wr, NULL);
+
+	ret = ib_post_recv(rdma->qp, &wr, NULL);
+	if (ret)
+		ib_dma_unmap_single(rdma->cm_id->device, c->busa,
+				    client->msize, DMA_FROM_DEVICE);
+	return ret;
 
  error:
 	p9_debug(P9_DEBUG_ERROR, "EIO\n");
@@ -499,7 +505,7 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 
 	if (down_interruptible(&rdma->sq_sem)) {
 		err = -EINTR;
-		goto send_error;
+		goto dma_unmap;
 	}
 
 	/* Mark request as `sent' *before* we actually send it,
@@ -509,11 +515,14 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
 	req->status = REQ_STATUS_SENT;
 	err = ib_post_send(rdma->qp, &wr, NULL);
 	if (err)
-		goto send_error;
+		goto dma_unmap;
 
 	/* Success */
 	return 0;
 
+dma_unmap:
+	ib_dma_unmap_single(rdma->cm_id->device, c->busa,
+			    c->req->tc.size, DMA_TO_DEVICE);
  /* Handle errors that happened during or while preparing the send: */
  send_error:
 	req->status = REQ_STATUS_ERROR;