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block: nbd: fix sanity check for first_minor

PATCH In review Yan, Zheng 2 participants 2 messages Oct 11, 2021

Subsystems (2)
Block layer Network block device (NBD)
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Yan, Zheng

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#0 lore raw

PATCH v2 1/1 block: nbd: fix sanity check for first_minor

From: "Yan, Zheng" <[email protected]>

Device's minor is a 20-bits number, max value is 0xfffff.

Fixes b1a811633f ("block: nbd: add sanity check for first_minor").
Signed-off-by "Yan, Zheng" <[email protected]>
---
 drivers/block/nbd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/block/nbd.c +2 -2
index 1183f7872b71..118039d35468 100644
@@ -1750,10 +1750,10 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
 
 	/* Too big first_minor can cause duplicate creation of
 	 * sysfs files/links, since first_minor will be truncated to
-	 * byte in __device_add_disk().
+	 * 20-bits number in __device_add_disk().
 	 */
 	disk->first_minor = index << part_shift;
-	if (disk->first_minor > 0xff) {
+	if (disk->first_minor > MINORMASK) {
 		err = -EINVAL;
 		goto out_free_idr;
 	}
Signature · 1 line
2.12.2
#1 lore raw
Quoted 3 lines · Zheng

From: "Yan, Zheng" <[email protected]>

Device's minor is a 20-bits number, max value is 0xfffff.

I'd just drop this check again now that we do have proper error handling in add_disk.