linux-kernel - [PATCH v2 2/4] zram: avoid disksize setting when device is being claimed

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Message-Id: <20210423011108.11988-3-mcgrof@kernel.org>
Date:   Fri, 23 Apr 2021 01:11:06 +0000
From:   Luis Chamberlain <mcgrof@...nel.org>
To:     minchan@...nel.org, ngupta@...are.org,
        sergey.senozhatsky.work@...il.com
Cc:     mcgrof@...nel.org, axboe@...nel.dk, mbenes@...e.com,
        jpoimboe@...hat.com, tglx@...utronix.de, keescook@...omium.org,
        jikos@...nel.org, rostedt@...dmis.org, peterz@...radead.org,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/4] zram: avoid disksize setting when device is being claimed

As with other areas of the zram diver, check if the zram
block device is being claimed but do it early to avoid
trying to set something up for a zram device which may
be on its way out.

This doesn't fix a known crash, however the potential for
an issue issue is found through code inspection.

Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
---
 drivers/block/zram/zram_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 431b60cd85c1..6051d20b88c3 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1729,7 +1729,7 @@ static ssize_t disksize_store(struct device *dev,
 
 	mutex_lock(&zram_index_mutex);
 
-	if (!zram_up) {
+	if (!zram_up || zram->claim) {
 		err = -ENODEV;
 		goto out;
 	}
-- 
2.27.0