From ed29f171518cbe11c81e8c20d393bb094a9e2ce7 Mon Sep 17 00:00:00 2001 From: Davidlohr Bueso Date: Mon, 3 Feb 2020 17:34:32 -0800 Subject: [PATCH] ipc/mqueue.c: remove duplicated code pipelined_send() and pipelined_receive() are identical, so merge them. [manfred@colorfullife.com: add changelog] Link: http://lkml.kernel.org/r/20191020123305.14715-3-manfred@colorfullife.com Signed-off-by: Davidlohr Bueso Signed-off-by: Manfred Spraul Cc: <1vier1@web.de> Cc: Peter Zijlstra Cc: Waiman Long Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- ipc/mqueue.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 3d920ff15c80..270456530f6a 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -918,6 +918,23 @@ out_name: * The same algorithm is used for senders. */ +static inline void __pipelined_op(struct wake_q_head *wake_q, + struct mqueue_inode_info *info, + struct ext_wait_queue *this) +{ + 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 + * write operation: As once set, the receiver can continue, + * and if we don't have the reference count from the wake_q, + * yet, at that point we can later have a use-after-free + * condition and bogus wakeup. + */ + this->state = STATE_READY; +} + /* pipelined_send() - send a message directly to the task waiting in * sys_mq_timedreceive() (without inserting message into a queue). */ @@ -927,17 +944,7 @@ static inline void pipelined_send(struct wake_q_head *wake_q, struct ext_wait_queue *receiver) { receiver->msg = message; - list_del(&receiver->list); - wake_q_add(wake_q, receiver->task); - /* - * Rely on the implicit cmpxchg barrier from wake_q_add such - * that we can ensure that updating receiver->state is the last - * write operation: As once set, the receiver can continue, - * and if we don't have the reference count from the wake_q, - * yet, at that point we can later have a use-after-free - * condition and bogus wakeup. - */ - receiver->state = STATE_READY; + __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,