Christoph Hellwig <h...@lst.de> writes: > Instead of handcoded non-null checks always initialize ki_list to an > empty list and use list_empty / list_empty_careful on it.
Yeah, who knows why list_empty wasn't used from the beginning. In the past, tricks were played by overwriting list pointers with non-null, but that wasn't the case here. > 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 <h...@lst.de> > --- > 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; So, this changes behavior from quietly overwriting the prior cancel function to not doing it. I don't think it matters one bit, though. Callers shouldn't do that. Acked-by: Jeff Moyer <jmo...@redhat.com>
