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Commit d0c6096b authored by Charan Teja Reddy's avatar Charan Teja Reddy Committed by Gerrit - the friendly Code Review server
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dma-buf: replace tasklist_lock with rcu lock 



tasklist_lock is not required while traversing the processes list.
Replace it with rcu_read_lock() which can help in avoiding the watchdog
bark/bite which scenario is expected when the writers does
write_lock_irq(&tasklist_lock) and the reader of the same lock who
acquired it first takes more time to release.

Change-Id: I1f2b7a23c85b30fa44eec6e7bff7258923382790
Signed-off-by: default avatarCharan Teja Reddy <charante@codeaurora.org>
parent 1e52b08a

drivers/dma-buf/dma-buf.c

+3 −3
Original line number Diff line number Diff line
@@ -1353,14 +1353,14 @@ static int dma_procs_debug_show(struct seq_file *s, void *unused) 
	struct dma_proc *tmp, *n;

	LIST_HEAD(plist);



	read_lock(&tasklist_lock);

	rcu_read_lock();

	for_each_process(task) {

		struct files_struct *group_leader_files = NULL;



		tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);

		if (!tmp) {

			ret = -ENOMEM;

			read_unlock(&tasklist_lock);

			rcu_read_unlock();

			goto mem_err;

		}

		INIT_LIST_HEAD(&tmp->dma_bufs);
@@ -1384,7 +1384,7 @@ static int dma_procs_debug_show(struct seq_file *s, void *unused) 
skip:

		free_proc(tmp);

	}

	read_unlock(&tasklist_lock);

	rcu_read_unlock();



	list_sort(NULL, &plist, proccmp);

	list_for_each_entry(tmp, &plist, head)