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 --- block/blk-mq.c | 2 +- block/blk-wbt.c | 2 +- block/kyber-iosched.c | 8 ++++---- 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'block') diff --git a/block/blk-mq.c b/block/blk-mq.c index a083f95e04b1b..121aa1dbb1921 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -933,7 +933,7 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, int fla hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait); - list_del(&wait->task_list); + list_del(&wait->entry); clear_bit_unlock(BLK_MQ_S_TAG_WAITING, &hctx->state); blk_mq_run_hw_queue(hctx, true); return 1; diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 5f3a37c2784c1..6a9a0f03a67bd 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -520,7 +520,7 @@ static inline bool may_queue(struct rq_wb *rwb, struct rq_wait *rqw, * in line to be woken up, wait for our turn. */ if (waitqueue_active(&rqw->wait) && - rqw->wait.task_list.next != &wait->task_list) + rqw->wait.head.next != &wait->entry) return false; return atomic_inc_below(&rqw->inflight, get_limit(rwb, rw)); diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c index b95d6bd714c07..9bf1484365b21 100644 --- a/block/kyber-iosched.c +++ b/block/kyber-iosched.c @@ -385,7 +385,7 @@ static int kyber_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) for (i = 0; i < KYBER_NUM_DOMAINS; i++) { INIT_LIST_HEAD(&khd->rqs[i]); - INIT_LIST_HEAD(&khd->domain_wait[i].task_list); + INIT_LIST_HEAD(&khd->domain_wait[i].entry); atomic_set(&khd->wait_index[i], 0); } @@ -512,7 +512,7 @@ static int kyber_domain_wake(wait_queue_entry_t *wait, unsigned mode, int flags, { struct blk_mq_hw_ctx *hctx = READ_ONCE(wait->private); - list_del_init(&wait->task_list); + list_del_init(&wait->entry); blk_mq_run_hw_queue(hctx, true); return 1; } @@ -536,7 +536,7 @@ static int kyber_get_domain_token(struct kyber_queue_data *kqd, * run when one becomes available. Note that this is serialized on * khd->lock, but we still need to be careful about the waker. */ - if (list_empty_careful(&wait->task_list)) { + if (list_empty_careful(&wait->entry)) { init_waitqueue_func_entry(wait, kyber_domain_wake); wait->private = hctx; ws = sbq_wait_ptr(domain_tokens, @@ -736,7 +736,7 @@ static int kyber_##name##_waiting_show(void *data, struct seq_file *m) \ struct kyber_hctx_data *khd = hctx->sched_data; \ wait_queue_entry_t *wait = &khd->domain_wait[domain]; \ \ - seq_printf(m, "%d\n", !list_empty_careful(&wait->task_list)); \ + seq_printf(m, "%d\n", !list_empty_careful(&wait->entry)); \ return 0; \ } KYBER_DEBUGFS_DOMAIN_ATTRS(KYBER_READ, read) -- cgit v1.2.3