[PATCH v2] RDMA/srpt: Fix srpt_alloc_rw_ctxs() unwind counters

[kensanya@163.com]

From: TanZheng <tanzheng@kylinos.cn>

When srpt_alloc_rw_ctxs() fails partway through a multi-buffer indirect
descriptor, the unwind path destroys RDMA contexts but leaves stale
n_rw_ctx and n_rdma values (and a dangling rw_ctxs pointer). Later
sq_wr_avail accounting in srpt_queue_response() or srpt_write_pending()
can then subtract the wrong number of send queue credits.

Reset the counters and clear rw_ctxs after freeing the heap
allocation before returning an error.

Fixes: b99f8e4d7bcd ("IB/srpt: convert to the generic RDMA READ/WRITE API")
Signed-off-by: TanZheng <tanzheng@kylinos.cn>
---
v2:
- After kfree(), set rw_ctxs to NULL instead of &s_rw_ctx
  (Leon Romanovsky)

 drivers/infiniband/ulp/srpt/ib_srpt.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index f66cfd70c263..a9c4995af7a3 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1014,8 +1014,12 @@ static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
 				ctx->sg, ctx->nents, dir);
 		target_free_sgl(ctx->sg, ctx->nents);
 	}
-	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
+	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx) {
 		kfree(ioctx->rw_ctxs);
+		ioctx->rw_ctxs = NULL;
+	}
+	ioctx->n_rw_ctx = 0;
+	ioctx->n_rdma = 0;
 	return ret;
 }
 
-- 
2.25.1