diff options
| author | Jason Gunthorpe <jgg@nvidia.com> | 2020-08-18 14:05:19 +0200 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2020-08-27 13:38:15 +0200 |
| commit | 308571debccd7004acf02ea1b7163a96ad772292 (patch) | |
| tree | 75134da6d7a03c9d5fc4ed96eb7bad0de2f5c42c /drivers/infiniband/core/ucma.c | |
| parent | RDMA/cma: Add missing locking to rdma_accept() (diff) | |
| download | linux-308571debccd7004acf02ea1b7163a96ad772292.tar.xz linux-308571debccd7004acf02ea1b7163a96ad772292.zip | |
RDMA/ucma: Do not use file->mut to lock destroying
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.
Link: https://lore.kernel.org/r/20200818120526.702120-8-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/infiniband/core/ucma.c')
| -rw-r--r-- | drivers/infiniband/core/ucma.c | 14 |
1 files 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 */ |