Instead of handcoded non-null checks always initialize ki_list to an empty list and use list_empty / list_empty_careful on it. While we're at it also error out on a double call to kiocb_set_cancel_fn instead of ignoring it. Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- fs/aio.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 496b50f9e9b1..fe241b5b44b2 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -555,13 +555,12 @@ void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) struct kioctx *ctx = req->ki_ctx; unsigned long flags; - spin_lock_irqsave(&ctx->ctx_lock, flags); - - if (!req->ki_list.next) - list_add(&req->ki_list, &ctx->active_reqs); + if (WARN_ON_ONCE(!list_empty(&req->ki_list))) + return; + spin_lock_irqsave(&ctx->ctx_lock, flags); + list_add_tail(&req->ki_list, &ctx->active_reqs); req->ki_cancel = cancel; - spin_unlock_irqrestore(&ctx->ctx_lock, flags); } EXPORT_SYMBOL(kiocb_set_cancel_fn); @@ -1034,7 +1033,7 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) goto out_put; percpu_ref_get(&ctx->reqs); - + INIT_LIST_HEAD(&req->ki_list); req->ki_ctx = ctx; return req; out_put: @@ -1080,7 +1079,7 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2) unsigned tail, pos, head; unsigned long flags; - if (iocb->ki_list.next) { + if (!list_empty_careful(iocb->ki_list.next)) { unsigned long flags; spin_lock_irqsave(&ctx->ctx_lock, flags); -- 2.14.2 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html