From 2055da97389a605c8a00d163d40903afbe413921 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 20 Jun 2017 12:06:46 +0200 Subject: sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming So I've noticed a number of instances where it was not obvious from the code whether ->task_list was for a wait-queue head or a wait-queue entry. Furthermore, there's a number of wait-queue users where the lists are not for 'tasks' but other entities (poll tables, etc.), in which case the 'task_list' name is actively confusing. To clear this all up, name the wait-queue head and entry list structure fields unambiguously: struct wait_queue_head::task_list => ::head struct wait_queue_entry::task_list => ::entry For example, this code: rqw->wait.task_list.next != &wait->task_list ... is was pretty unclear (to me) what it's doing, while now it's written this way: rqw->wait.head.next != &wait->entry ... which makes it pretty clear that we are iterating a list until we see the head. Other examples are: list_for_each_entry_safe(pos, next, &x->task_list, task_list) { list_for_each_entry(wq, &fence->wait.task_list, task_list) { ... where it's unclear (to me) what we are iterating, and during review it's hard to tell whether it's trying to walk a wait-queue entry (which would be a bug), while now it's written as: list_for_each_entry_safe(pos, next, &x->head, entry) { list_for_each_entry(wq, &fence->wait.head, entry) { Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/wait.h | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'include/linux/wait.h') diff --git a/include/linux/wait.h b/include/linux/wait.h index 629489746f8a..b289c96151ee 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -26,12 +26,12 @@ struct wait_queue_entry { unsigned int flags; void *private; wait_queue_func_t func; - struct list_head task_list; + struct list_head entry; }; struct wait_queue_head { spinlock_t lock; - struct list_head task_list; + struct list_head head; }; typedef struct wait_queue_head wait_queue_head_t; @@ -44,14 +44,14 @@ struct task_struct; #define __WAITQUEUE_INITIALIZER(name, tsk) { \ .private = tsk, \ .func = default_wake_function, \ - .task_list = { NULL, NULL } } + .entry = { NULL, NULL } } #define DECLARE_WAITQUEUE(name, tsk) \ struct wait_queue_entry name = __WAITQUEUE_INITIALIZER(name, tsk) #define __WAIT_QUEUE_HEAD_INITIALIZER(name) { \ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ - .task_list = { &(name).task_list, &(name).task_list } } + .head = { &(name).head, &(name).head } } #define DECLARE_WAIT_QUEUE_HEAD(name) \ struct wait_queue_head name = __WAIT_QUEUE_HEAD_INITIALIZER(name) @@ -121,7 +121,7 @@ init_waitqueue_func_entry(struct wait_queue_entry *wq_entry, wait_queue_func_t f */ static inline int waitqueue_active(struct wait_queue_head *wq_head) { - return !list_empty(&wq_head->task_list); + return !list_empty(&wq_head->head); } /** @@ -151,7 +151,7 @@ extern void remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue static inline void __add_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { - list_add(&wq_entry->task_list, &wq_head->task_list); + list_add(&wq_entry->entry, &wq_head->head); } /* @@ -166,7 +166,7 @@ __add_wait_queue_exclusive(struct wait_queue_head *wq_head, struct wait_queue_en static inline void __add_wait_queue_entry_tail(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { - list_add_tail(&wq_entry->task_list, &wq_head->task_list); + list_add_tail(&wq_entry->entry, &wq_head->head); } static inline void @@ -179,7 +179,7 @@ __add_wait_queue_entry_tail_exclusive(struct wait_queue_head *wq_head, struct wa static inline void __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry) { - list_del(&wq_entry->task_list); + list_del(&wq_entry->entry); } void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key); @@ -952,7 +952,7 @@ int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, i struct wait_queue_entry name = { \ .private = current, \ .func = function, \ - .task_list = LIST_HEAD_INIT((name).task_list), \ + .entry = LIST_HEAD_INIT((name).entry), \ } #define DEFINE_WAIT(name) DEFINE_WAIT_FUNC(name, autoremove_wake_function) @@ -961,7 +961,7 @@ int autoremove_wake_function(struct wait_queue_entry *wq_entry, unsigned mode, i do { \ (wait)->private = current; \ (wait)->func = autoremove_wake_function; \ - INIT_LIST_HEAD(&(wait)->task_list); \ + INIT_LIST_HEAD(&(wait)->entry); \ (wait)->flags = 0; \ } while (0) -- cgit