[PATCH v4 1/2] Staging: zram: Fix variable dereferenced before check

[Rashika Kheria]

This patch fixes the following Smatch warning in zram_drv.c-
drivers/staging/zram/zram_drv.c:663
reset_store() warn: variable dereferenced before check 'bdev' (see line 652)
drivers/staging/zram/zram_drv.c:899
destroy_device() warn: variable dereferenced before check 'zram->disk' (see 
line 896)

Signed-off-by: Rashika Kheria <rashika.khe...@gmail.com>
---

This revision fixes the following issues of the previous revision:
Remove unnecessary checks

 drivers/staging/zram/zram_drv.c |   16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 2c4ed52..8679a06 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -648,6 +648,9 @@ static ssize_t reset_store(struct device *dev,
        zram = dev_to_zram(dev);
        bdev = bdget_disk(zram->disk, 0);
 
+       if (!bdev)
+               return -EBUSY;
+
        /* Do not reset an active device! */
        if (bdev->bd_holders)
                return -EBUSY;
@@ -660,8 +663,7 @@ static ssize_t reset_store(struct device *dev,
                return -EINVAL;
 
        /* Make sure all pending I/O is finished */
-       if (bdev)
-               fsync_bdev(bdev);
+       fsync_bdev(bdev);
 
        zram_reset_device(zram, true);
        return len;
@@ -895,14 +897,10 @@ static void destroy_device(struct zram *zram)
 {
        sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
                        &zram_disk_attr_group);
+       del_gendisk(zram->disk);
+       put_disk(zram->disk);
 
-       if (zram->disk) {
-               del_gendisk(zram->disk);
-               put_disk(zram->disk);
-       }
-
-       if (zram->queue)
-               blk_cleanup_queue(zram->queue);
+       blk_cleanup_queue(zram->queue);
 }
 
 static int __init zram_init(void)
-- 
1.7.9.5

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