From: Leon Romanovsky <leon@kernel.org>
To: Doug Ledford <dledford@redhat.com>, Jason Gunthorpe <jgg@nvidia.com>
Cc: Leon Romanovsky <leonro@mellanox.com>, linux-rdma@vger.kernel.org
Subject: [PATCH rdma-next 07/14] RDMA/ucma: Do not use file->mut to lock destroying
Date: Tue, 18 Aug 2020 15:05:19 +0300 [thread overview]
Message-ID: <20200818120526.702120-8-leon@kernel.org> (raw)
In-Reply-To: <20200818120526.702120-1-leon@kernel.org>
From: Jason Gunthorpe <jgg@nvidia.com>
The only reader of destroying is inside a handler under the handler_mutex,
so directly use the handler_mutex when setting it instead of the larger
file->mut.
As the refcount could be zero here, and the cm_id already freed, and
additional refcount grab around the locking is required to touch the
cm_id.
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
drivers/infiniband/core/ucma.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index add1ece38739..18285941aec3 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -602,9 +602,17 @@ static int ucma_free_ctx(struct ucma_context *ctx)
static int __destroy_id(struct ucma_context *ctx)
{
- mutex_lock(&ctx->file->mut);
- ctx->destroying = 1;
- mutex_unlock(&ctx->file->mut);
+ /*
+ * If the refcount is already 0 then ucma_close_id() has already
+ * destroyed the cm_id, otherwise holding the refcount keeps cm_id
+ * valid. Prevent queue_work() from being called.
+ */
+ if (refcount_inc_not_zero(&ctx->ref)) {
+ rdma_lock_handler(ctx->cm_id);
+ ctx->destroying = 1;
+ rdma_unlock_handler(ctx->cm_id);
+ ucma_put_ctx(ctx);
+ }
flush_workqueue(ctx->file->close_wq);
/* At this point it's guaranteed that there is no inflight closing task */
--
2.26.2
next prev parent reply other threads:[~2020-08-18 12:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-18 12:05 [PATCH rdma-next 00/14] Cleanup locking and events in ucma Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 01/14] RDMA/ucma: Fix refcount 0 incr in ucma_get_ctx() Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 02/14] RDMA/ucma: Remove unnecessary locking of file->ctx_list in close Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 03/14] RDMA/ucma: Consolidate the two destroy flows Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 04/14] RDMA/ucma: Fix error cases around ucma_alloc_ctx() Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 05/14] RDMA/ucma: Remove mc_list and rely on xarray Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 06/14] RDMA/cma: Add missing locking to rdma_accept() Leon Romanovsky
2021-02-09 14:46 ` Chuck Lever
2021-02-09 15:40 ` Jason Gunthorpe
2020-08-18 12:05 ` Leon Romanovsky [this message]
2020-08-18 12:05 ` [PATCH rdma-next 08/14] RDMA/ucma: Fix the locking of ctx->file Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 09/14] RDMA/ucma: Fix locking for ctx->events_reported Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 10/14] RDMA/ucma: Add missing locking around rdma_leave_multicast() Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 11/14] RDMA/ucma: Change backlog into an atomic Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 12/14] RDMA/ucma: Narrow file->mut in ucma_event_handler() Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 13/14] RDMA/ucma: Rework how new connections are passed through event delivery Leon Romanovsky
2020-08-18 12:05 ` [PATCH rdma-next 14/14] RDMA/ucma: Remove closing and the close_wq Leon Romanovsky
2020-08-27 11:39 ` [PATCH rdma-next 00/14] Cleanup locking and events in ucma Jason Gunthorpe
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