Commit 07e266a7 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/ucma: Remove unnecessary locking of file->ctx_list in close 

During the file_operations release function it is already not possible
that write() can be running concurrently, remove the extra locking
around the ctx_list.

Link: https://lore.kernel.org/r/20200818120526.702120-3-leon@kernel.org


Signed-off-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent ca2968c1

drivers/infiniband/core/ucma.c

+7 −4
Original line number Diff line number Diff line
@@ -1824,12 +1824,17 @@ static int ucma_close(struct inode *inode, struct file *filp) 
	struct ucma_file *file = filp->private_data;

	struct ucma_context *ctx, *tmp;



	mutex_lock(&file->mut);

	/*

	 * ctx_list can only be mutated under the write(), which is no longer

	 * possible, so no locking needed.

	 */

	list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) {

		xa_erase(&ctx_table, ctx->id);



		mutex_lock(&file->mut);

		ctx->destroying = 1;

		mutex_unlock(&file->mut);



		xa_erase(&ctx_table, ctx->id);

		flush_workqueue(file->close_wq);

		/* At that step once ctx was marked as destroying and workqueue

		 * was flushed we are safe from any inflights handlers that
@@ -1849,9 +1854,7 @@ static int ucma_close(struct inode *inode, struct file *filp) 
		}



		ucma_free_ctx(ctx);

		mutex_lock(&file->mut);

	}

	mutex_unlock(&file->mut);

	destroy_workqueue(file->close_wq);

	kfree(file);

	return 0;

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