On Tue, Jun 14, 2022 at 5:26 PM Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
>
> On Tue, Jun 14, 2022 at 5:14 PM Dongliang Mu <dzm91@xxxxxxxxxxx> wrote:
> >
> > From: mudongliang <mudongliangabcd@xxxxxxxxx>
> >
> > kfree can handle NULL pointer as its argument.
> > According to coccinelle isnullfree check, remove NULL check
> > before kfree operation.
> >
> > Signed-off-by: mudongliang <mudongliangabcd@xxxxxxxxx>
> > ---
> > fs/io_uring.c | 15 +++++----------
> > 1 file changed, 5 insertions(+), 10 deletions(-)
> >
> > diff --git a/fs/io_uring.c b/fs/io_uring.c
> > index 3aab4182fd89..bec47eae2a9b 100644
> > --- a/fs/io_uring.c
> > +++ b/fs/io_uring.c
> > @@ -3159,8 +3159,7 @@ static void io_free_batch_list(struct io_ring_ctx *ctx,
> > if ((req->flags & REQ_F_POLLED) && req->apoll) {
> > struct async_poll *apoll = req->apoll;
> >
> > - if (apoll->double_poll)
> > - kfree(apoll->double_poll);
> > + kfree(apoll->double_poll);
> > list_add(&apoll->poll.wait.entry,
> > &ctx->apoll_cache);
> > req->flags &= ~REQ_F_POLLED;
> > @@ -4499,8 +4498,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
> > kiocb_done(req, ret, issue_flags);
> > out_free:
> > /* it's faster to check here then delegate to kfree */
>
> I am feeling you are not on the right way. See the comment
> here.
Thanks for your reply. I ignore them previously. Any method to make
coccicheck ignore such cases?
>
> Thanks.
>
> > - if (iovec)
> > - kfree(iovec);
> > + kfree(iovec);
> > return 0;
> > }
> >
> > @@ -4602,8 +4600,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
> > }
> > out_free:
> > /* it's reportedly faster than delegating the null check to kfree() */
>
> See here.
>
> > - if (iovec)
> > - kfree(iovec);
> > + kfree(iovec);
> > return ret;
> > }
> >
> > @@ -6227,8 +6224,7 @@ static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
> > req_set_fail(req);
> > }
> > /* fast path, check for non-NULL to avoid function call */
>
> here.
>
> > - if (kmsg->free_iov)
> > - kfree(kmsg->free_iov);
> > + kfree(kmsg->free_iov);
> > req->flags &= ~REQ_F_NEED_CLEANUP;
> > if (ret >= 0)
> > ret += sr->done_io;
> > @@ -6481,8 +6477,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
> > }
> >
> > /* fast path, check for non-NULL to avoid function call */
>
> And here.
>
> > - if (kmsg->free_iov)
> > - kfree(kmsg->free_iov);
> > + kfree(kmsg->free_iov);
> > req->flags &= ~REQ_F_NEED_CLEANUP;
> > if (ret >= 0)
> > ret += sr->done_io;
> > --
> > 2.35.1
> >
