Re: [dm-devel] [PATCH 4/8] block: support delayed holder registration
From: Guenter Roeck <linux@roeck-us.net>
Date: 2021-08-21 03:17:06
Also in:
dm-devel
On 8/20/21 8:08 AM, Christoph Hellwig wrote:
Please try the patch below: ---quoted
From 7609266da56160d211662cd2fbe26570aad11b15 Mon Sep 17 00:00:00 2001From: Christoph Hellwig <hch@lst.de> Date: Fri, 20 Aug 2021 17:00:11 +0200 Subject: mtd_blkdevs: don't hold del_mtd_blktrans_dev in blktrans_{open,release} There is nothing that this protects against except for slightly reducing the window when new opens can appear just before calling del_gendisk. Signed-off-by: Christoph Hellwig <hch@lst.de>
A cautious Tested-by: Guenter Roeck <linux@roeck-us.net> Cautious because -next is a bit broken right now and I can not run a complete test for all images. Guenter
quoted hunk ↗ jump to hunk
--- drivers/mtd/mtd_blkdevs.c | 5 ----- 1 file changed, 5 deletions(-)diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 44bea3f65060..6b81a1c9ccbe 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c@@ -207,7 +207,6 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode) if (!dev) return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ - mutex_lock(&mtd_table_mutex); mutex_lock(&dev->lock); if (dev->open)@@ -233,7 +232,6 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode) unlock: dev->open++; mutex_unlock(&dev->lock); - mutex_unlock(&mtd_table_mutex); blktrans_dev_put(dev); return ret;@@ -244,7 +242,6 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode) module_put(dev->tr->owner); kref_put(&dev->ref, blktrans_dev_release); mutex_unlock(&dev->lock); - mutex_unlock(&mtd_table_mutex); blktrans_dev_put(dev); return ret; }@@ -256,7 +253,6 @@ static void blktrans_release(struct gendisk *disk, fmode_t mode) if (!dev) return; - mutex_lock(&mtd_table_mutex); mutex_lock(&dev->lock); if (--dev->open)@@ -272,7 +268,6 @@ static void blktrans_release(struct gendisk *disk, fmode_t mode) } unlock: mutex_unlock(&dev->lock); - mutex_unlock(&mtd_table_mutex); blktrans_dev_put(dev); }