checkpatch: check for uncommented waitqueue_active()
Linus sayeth: : Pretty much every single time people use this "if : (waitqueue_active())" model, it tends to be a bug, because it means : that there is zero serialization with people who are just about to go : to sleep. It's fundamentally racy against all the "wait_event()" loops : that carefully do memory barriers between testing conditions and going : to sleep, because the memory barriers now don't exist on the waking : side. : : So I'm making a new rule: if you use waitqueue_active(), I want an : explanation for why it's not racy with the waiter. A big comment about : the memory ordering, or about higher-level locks that are held by the : caller, or something. Signed-off-by:Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
parent
cbdc2810
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