[PATCH V15 02/22] mmc: block: Simplify cleaning up the queue

From: Adrian Hunter <adrian.hunter@intel.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-mmc <linux-mmc@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Bough Chen <haibo.chen@nxp.com>,
	Alex Lemberg <alex.lemberg@sandisk.com>,
	Mateusz Nowak <mateusz.nowak@intel.com>,
	Yuliy Izrailov <Yuliy.Izrailov@sandisk.com>,
	Jaehoon Chung <jh80.chung@samsung.com>,
	Dong Aisheng <dongas86@gmail.com>,
	Das Asutosh <asutoshd@codeaurora.org>,
	Zhangfei Gao <zhangfei.gao@gmail.com>,
	Sahitya Tummala <stummala@codeaurora.org>,
	Harjani Ritesh <riteshh@codeaurora.org>,
	Venu Byravarasu <vbyravarasu@nvidia.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Shawn Lin <shawn.lin@rock-chips.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Christoph Hellwig <hch@lst.de>
Subject: [PATCH V15 02/22] mmc: block: Simplify cleaning up the queue
Date: Wed, 29 Nov 2017 15:40:59 +0200	[thread overview]
Message-ID: <1511962879-24262-3-git-send-email-adrian.hunter@intel.com> (raw)
In-Reply-To: <1511962879-24262-1-git-send-email-adrian.hunter@intel.com>

Use blk_cleanup_queue() to shutdown the queue when the driver is removed,
and instead get an extra reference to the queue to prevent the queue being
freed before the final mmc_blk_put().

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/core/block.c | 17 ++++++++++++-----
 drivers/mmc/core/queue.c |  2 ++
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index ccfa98af1dd3..e44f6d90aeb4 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -189,7 +189,7 @@ static void mmc_blk_put(struct mmc_blk_data *md)
 	md->usage--;
 	if (md->usage == 0) {
 		int devidx = mmc_get_devidx(md->disk);
-		blk_cleanup_queue(md->queue.queue);
+		blk_put_queue(md->queue.queue);
 		ida_simple_remove(&mmc_blk_ida, devidx);
 		put_disk(md->disk);
 		kfree(md);
@@ -2156,6 +2156,17 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
 
 	md->queue.blkdata = md;
 
+	/*
+	 * Keep an extra reference to the queue so that we can shutdown the
+	 * queue (i.e. call blk_cleanup_queue()) while there are still
+	 * references to the 'md'. The corresponding blk_put_queue() is in
+	 * mmc_blk_put().
+	 */
+	if (!blk_get_queue(md->queue.queue)) {
+		mmc_cleanup_queue(&md->queue);
+		goto err_putdisk;
+	}
+
 	md->disk->major	= MMC_BLOCK_MAJOR;
 	md->disk->first_minor = devidx * perdev_minors;
 	md->disk->fops = &mmc_bdops;
@@ -2471,10 +2482,6 @@ static void mmc_blk_remove_req(struct mmc_blk_data *md)
 		 * from being accepted.
 		 */
 		card = md->queue.card;
-		spin_lock_irq(md->queue.queue->queue_lock);
-		queue_flag_set(QUEUE_FLAG_BYPASS, md->queue.queue);
-		spin_unlock_irq(md->queue.queue->queue_lock);
-		blk_set_queue_dying(md->queue.queue);
 		mmc_cleanup_queue(&md->queue);
 		if (md->disk->flags & GENHD_FL_UP) {
 			device_remove_file(disk_to_dev(md->disk), &md->force_ro);
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 26f8da30ebe5..ae6d9da68735 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -268,6 +268,8 @@ void mmc_cleanup_queue(struct mmc_queue *mq)
 	blk_start_queue(q);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
+	blk_cleanup_queue(q);
+
 	mq->card = NULL;
 }
 
-- 
1.9.1
