aio: sanitize ki_list handling

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@lst.de>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig 2018-04-09 14:57:56 +02:00
parent c213dc826c
commit 75321b50a3

View file

@ -553,13 +553,12 @@ void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
struct kioctx *ctx = req->ki_ctx;
unsigned long flags;
if (WARN_ON_ONCE(!list_empty(&req->ki_list)))
return;
spin_lock_irqsave(&ctx->ctx_lock, flags);
if (!req->ki_list.next)
list_add(&req->ki_list, &ctx->active_reqs);
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);
@ -1039,7 +1038,7 @@ 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:
@ -1107,7 +1106,7 @@ static void aio_complete(struct kiocb *kiocb, long res, long res2)
file_end_write(file);
}
if (iocb->ki_list.next) {
if (!list_empty_careful(&iocb->ki_list)) {
unsigned long flags;
spin_lock_irqsave(&ctx->ctx_lock, flags);