linux-kernel - [PATCH 3/3] block: Stop abusing rq->csd.list in blk-softirq

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Date:	Wed, 18 Dec 2013 16:25:02 +0100
From:	Jan Kara <jack@...e.cz>
To:	Jens Axboe <jaxboe@...ionio.com>
Cc:	Christoph Hellwig <hch@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>, Jan Kara <jack@...e.cz>
Subject: [PATCH 3/3] block: Stop abusing rq->csd.list in blk-softirq

Abusing rq->csd.list for a list of requests to complete is rather ugly.
Especially since using queuelist should be safe and much cleaner.

Signed-off-by: Jan Kara <jack@...e.cz>
---
 block/blk-softirq.c | 12 ++++++------
 include/linux/smp.h |  6 +-----
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index 57790c1a97eb..7ea5534096d5 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -30,8 +30,8 @@ static void blk_done_softirq(struct softirq_action *h)
 	while (!list_empty(&local_list)) {
 		struct request *rq;
 
-		rq = list_entry(local_list.next, struct request, csd.list);
-		list_del_init(&rq->csd.list);
+		rq = list_entry(local_list.next, struct request, queuelist);
+		list_del_init(&rq->queuelist);
 		rq->q->softirq_done_fn(rq);
 	}
 }
@@ -45,9 +45,9 @@ static void trigger_softirq(void *data)
 
 	local_irq_save(flags);
 	list = this_cpu_ptr(&blk_cpu_done);
-	list_add_tail(&rq->csd.list, list);
+	list_add_tail(&rq->queuelist, list);
 
-	if (list->next == &rq->csd.list)
+	if (list->next == &rq->queuelist)
 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
 
 	local_irq_restore(flags);
@@ -136,7 +136,7 @@ void __blk_complete_request(struct request *req)
 		struct list_head *list;
 do_local:
 		list = this_cpu_ptr(&blk_cpu_done);
-		list_add_tail(&req->csd.list, list);
+		list_add_tail(&req->queuelist, list);
 
 		/*
 		 * if the list only contains our just added request,
@@ -144,7 +144,7 @@ do_local:
 		 * entries there, someone already raised the irq but it
 		 * hasn't run yet.
 		 */
-		if (list->next == &req->csd.list)
+		if (list->next == &req->queuelist)
 			raise_softirq_irqoff(BLOCK_SOFTIRQ);
 	} else if (raise_blk_irq(ccpu, req))
 		goto do_local;
diff --git a/include/linux/smp.h b/include/linux/smp.h
index c0f38018c195..9a1b8ba05924 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -17,11 +17,7 @@ extern void cpu_idle(void);
 
 typedef void (*smp_call_func_t)(void *info);
 struct call_single_data {
-	/* We still need list_head because of abuse by a block layer */
-	union {
-		struct list_head list;
-		struct llist_node llist;
-	};
+	struct llist_node llist;
 	smp_call_func_t func;
 	void *info;
 	u16 flags;
-- 
1.8.1.4

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