From: Zhihao Cheng <chengzhihao1@huawei.com>
To: <miquel.raynal@bootlin.com>, <richard@nod.at>, <vigneshr@ti.com>
Cc: <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
<chengzhihao1@huawei.com>, <yukuai3@huawei.com>
Subject: [PATCH 6/6] Revert "mtd: allow to unload the mtdtrans module if its block devices aren't open"
Date: Sun, 13 Jun 2021 19:30:35 +0800 [thread overview]
Message-ID: <20210613113035.2329421-7-chengzhihao1@huawei.com> (raw)
In-Reply-To: <20210613113035.2329421-1-chengzhihao1@huawei.com>
This reverts commit 008c751ec78587dd9b48bb62d4b10d616554fea2.
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
---
drivers/mtd/mtd_blkdevs.c | 49 ++++++++++++++++++++-------------------
1 file changed, 25 insertions(+), 24 deletions(-)
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index e8a77f10ae24..4d386617fd8a 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -205,7 +205,7 @@ static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
static int blktrans_open(struct block_device *bdev, fmode_t mode)
{
struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
- int ret = 0;
+ int ret;
if (!dev)
return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
@@ -213,17 +213,17 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
mutex_lock(&mtd_blkdevs_mutex);
mutex_lock(&dev->lock);
- if (dev->open++)
+ if (!dev->mtd) {
+ ret = -ENXIO;
goto unlock;
-
- kref_get(&dev->ref);
- __module_get(dev->tr->owner);
-
- if (dev->mtd) {
- ret = dev->tr->open ? dev->tr->open(dev) : 0;
- __get_mtd_device(dev->mtd);
}
+ ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0;
+ /* Take another reference on the device so it won't go away till
+ * last release */
+ if (!ret)
+ kref_get(&dev->ref);
+
dev->file_mode = mode;
unlock:
@@ -243,17 +243,14 @@ static void blktrans_release(struct gendisk *disk, fmode_t mode)
mutex_lock(&mtd_blkdevs_mutex);
mutex_lock(&dev->lock);
- if (--dev->open)
- goto unlock;
-
+ /* Release one reference, we sure its not the last one here*/
kref_put(&dev->ref, blktrans_dev_release);
- module_put(dev->tr->owner);
- if (dev->mtd) {
- if (dev->tr->release)
- dev->tr->release(dev);
- __put_mtd_device(dev->mtd);
- }
+ if (!dev->mtd)
+ goto unlock;
+
+ if (!--dev->open && dev->tr->release)
+ dev->tr->release(dev);
unlock:
mutex_unlock(&dev->lock);
blktrans_dev_put(dev);
@@ -408,6 +405,9 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
gd->queue = new->rq;
+ __get_mtd_device(new->mtd);
+ __module_get(tr->owner);
+
if (new->readonly)
set_disk_ro(gd, 1);
@@ -456,15 +456,16 @@ int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
blk_mq_unquiesce_queue(old->rq);
blk_mq_unfreeze_queue(old->rq);
- /* If the device is currently open, tell trans driver to close it,
- then put mtd device, and don't touch it again */
+ /* Ask trans driver for release to the mtd device */
mutex_lock(&old->lock);
- if (old->open) {
- if (old->tr->release)
- old->tr->release(old);
- __put_mtd_device(old->mtd);
+ if (old->open && old->tr->release) {
+ old->tr->release(old);
+ old->open = 0;
}
+ __put_mtd_device(old->mtd);
+ module_put(old->tr->owner);
+ /* At that point, we don't touch the mtd anymore */
old->mtd = NULL;
mutex_unlock(&old->lock);
--
2.31.1
next prev parent reply other threads:[~2021-06-13 11:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-13 11:30 [PATCH 0/6] Fix deadlock in ftl formating on mtd Zhihao Cheng
2021-06-13 11:30 ` [PATCH 1/6] Revert "mtd: blkdevs: fix potential deadlock + lockdep warnings" Zhihao Cheng
2021-06-13 11:30 ` [PATCH 2/6] Revert "mtd: fix: avoid race condition when accessing mtd->usecount" Zhihao Cheng
2021-06-13 11:30 ` [PATCH 3/6] Revert "mtd: mtd_blkdevs: don't increase 'open' count on error path" Zhihao Cheng
2021-06-13 11:30 ` [PATCH 4/6] Revert "mtd: mtd_blkdevs: fix error path in blktrans_open" Zhihao Cheng
2021-06-13 11:30 ` [PATCH 5/6] Revert "mtd: Remove redundant mutex from mtd_blkdevs.c" Zhihao Cheng
2021-06-13 11:30 ` Zhihao Cheng [this message]
2021-06-13 15:12 ` [PATCH 0/6] Fix deadlock in ftl formating on mtd Miquel Raynal
2021-06-15 9:02 ` Zhihao Cheng
2021-06-15 9:08 ` Zhihao Cheng
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