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authorIngo Molnar <mingo@kernel.org>2017-06-20 12:06:46 +0200
committerIngo Molnar <mingo@kernel.org>2017-06-20 12:19:14 +0200
commit2055da97389a605c8a00d163d40903afbe413921 (patch)
tree6aec7243076aab2d4d239f03e34598752ce1512a /mm
parent5822a454d6d22297c5fcd66264120587b2ec21cd (diff)
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 <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c2
-rw-r--r--mm/memcontrol.c2
-rw-r--r--mm/shmem.c4
3 files changed, 4 insertions, 4 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 80c19ee81e95..926484561624 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -845,7 +845,7 @@ static inline int wait_on_page_bit_common(wait_queue_head_t *q,
for (;;) {
spin_lock_irq(&q->lock);
- if (likely(list_empty(&wait->task_list))) {
+ if (likely(list_empty(&wait->entry))) {
if (lock)
__add_wait_queue_entry_tail_exclusive(q, wait);
else
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9a90b096dc6b..d75b38b66ef6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1570,7 +1570,7 @@ bool mem_cgroup_oom_synchronize(bool handle)
owait.wait.flags = 0;
owait.wait.func = memcg_oom_wake_function;
owait.wait.private = current;
- INIT_LIST_HEAD(&owait.wait.task_list);
+ INIT_LIST_HEAD(&owait.wait.entry);
prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
mem_cgroup_mark_under_oom(memcg);
diff --git a/mm/shmem.c b/mm/shmem.c
index a6c7dece4660..fdc413f82a99 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1905,7 +1905,7 @@ unlock:
static int synchronous_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
int ret = default_wake_function(wait, mode, sync, key);
- list_del_init(&wait->task_list);
+ list_del_init(&wait->entry);
return ret;
}
@@ -2840,7 +2840,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
spin_lock(&inode->i_lock);
inode->i_private = NULL;
wake_up_all(&shmem_falloc_waitq);
- WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.task_list));
+ WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.head));
spin_unlock(&inode->i_lock);
error = 0;
goto out;