Re: [PATCH 2/6] ipc/mqueue.c: Remove duplicated code

[Davidlohr Bueso]

On Sat, 12 Oct 2019, Manfred Spraul wrote:

> Patch entirely from Davidlohr:
> pipelined_send() and pipelined_receive() are identical, so merge them.

Sorry, yeah feel free to add my:

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>

> Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> ---
> ipc/mqueue.c | 31 ++++++++++++++++++-------------
> 1 file changed, 18 insertions(+), 13 deletions(-)
>
> diff --git a/ipc/mqueue.c b/ipc/mqueue.c
> index 3d920ff15c80..be48c0ba92f7 100644
> --- a/ipc/mqueue.c
> +++ b/ipc/mqueue.c
> @@ -918,17 +918,12 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
>  * The same algorithm is used for senders.
>  */
>
> -/* pipelined_send() - send a message directly to the task waiting in
> - * sys_mq_timedreceive() (without inserting message into a queue).
> - */
> -static inline void pipelined_send(struct wake_q_head *wake_q,
> +static inline void __pipelined_op(struct wake_q_head *wake_q,
> 				  struct mqueue_inode_info *info,
> -				  struct msg_msg *message,
> -				  struct ext_wait_queue *receiver)
> +				  struct ext_wait_queue *this)
> {
> -	receiver->msg = message;
> -	list_del(&receiver->list);
> -	wake_q_add(wake_q, receiver->task);
> +	list_del(&this->list);
> +	wake_q_add(wake_q, this->task);
> 	/*
> 	 * Rely on the implicit cmpxchg barrier from wake_q_add such
> 	 * that we can ensure that updating receiver->state is the last
> @@ -937,7 +932,19 @@ static inline void pipelined_send(struct wake_q_head *wake_q,
> 	 * yet, at that point we can later have a use-after-free
> 	 * condition and bogus wakeup.
> 	 */
> -	receiver->state = STATE_READY;
> +        this->state = STATE_READY;
> +}
> +
> +/* pipelined_send() - send a message directly to the task waiting in
> + * sys_mq_timedreceive() (without inserting message into a queue).
> + */
> +static inline void pipelined_send(struct wake_q_head *wake_q,
> +				  struct mqueue_inode_info *info,
> +				  struct msg_msg *message,
> +				  struct ext_wait_queue *receiver)
> +{
> +	receiver->msg = message;
> +	__pipelined_op(wake_q, info, receiver);
> }
>
> /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
> @@ -955,9 +962,7 @@ static inline void pipelined_receive(struct wake_q_head *wake_q,
> 	if (msg_insert(sender->msg, info))
> 		return;
>
> -	list_del(&sender->list);
> -	wake_q_add(wake_q, sender->task);
> -	sender->state = STATE_READY;
> +	__pipelined_op(wake_q, info, sender);
> }
>
> static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
> --
> 2.21.0