Re: [PATCH] zram: fix umount-reset_store-mount race condition
From: Sergey Senozhatsky
Date: Tue Feb 03 2015 - 09:51:32 EST
On (02/03/15 23:15), Sergey Senozhatsky wrote:
> > How about keep this here? Protected by zram->init_lock.
> > set_capacity(zram->disk, 0);
>
> why?
>
yeah, I see why. good catch.
hm, why do we perform destroy_device() before zram_reset_device() in
zram_exit()?
how about doing something like this (I don't want to return
that bool param back):
---
drivers/block/zram/zram_drv.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a32069f..386f7ed 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -736,6 +736,7 @@ static void zram_reset_device(struct zram *zram)
memset(&zram->stats, 0, sizeof(zram->stats));
zram->disksize = 0;
+ set_capacity(zram->disk, 0);
up_write(&zram->init_lock);
}
@@ -828,7 +829,6 @@ static ssize_t reset_store(struct device *dev,
/* Make sure all pending I/O is finished */
fsync_bdev(bdev);
zram_reset_device(zram);
- set_capacity(zram->disk, 0);
mutex_unlock(&bdev->bd_mutex);
revalidate_disk(zram->disk);
@@ -1178,12 +1178,8 @@ static void __exit zram_exit(void)
for (i = 0; i < num_devices; i++) {
zram = &zram_devices[i];
- destroy_device(zram);
- /*
- * Shouldn't access zram->disk after destroy_device
- * because destroy_device already released zram->disk.
- */
zram_reset_device(zram);
+ destroy_device(zram);
}
unregister_blkdev(zram_major, "zram");
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