[PATCH 0/2]null_blk: small fixes for zoned mode

[PATCH 0/2]null_blk: small fixes for zoned mode

[Chaitanya Kulkarni]

Hi,

This is a small patch-series which fixes potential oops for zoned mode.
Also, it disables the discard when nullb configured as zoned for
membacked mode.

Regards,
Chaitanya

Chaitanya Kulkarni (2):
  null_blk: return error for invalid zone size
  null_blk: don't allow discard for zoned mode

 drivers/block/null_blk_main.c  | 7 +++++++
 drivers/block/null_blk_zoned.c | 4 ++++
 2 files changed, 11 insertions(+)

-- 
2.22.1

[PATCH 1/2] null_blk: return error for invalid zone size

[Chaitanya Kulkarni]

In null_init_zone_dev() check if the zone size is larger than device
capacity, return error if needed.

This also fixes the following oops :-

null_blk: changed the number of conventional zones to 4294967295
BUG: kernel NULL pointer dereference, address: 0000000000000010
PGD 7d76c5067 P4D 7d76c5067 PUD 7d240c067 PMD 0
Oops: 0002 [#1] SMP NOPTI
CPU: 4 PID: 5508 Comm: nullbtests.sh Tainted: G OE 5.7.0-rc4lblk-fnext0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e4
RIP: 0010:null_init_zoned_dev+0x17a/0x27f [null_blk]
RSP: 0018:ffffc90007007e00 EFLAGS: 00010246
RAX: 0000000000000020 RBX: ffff8887fb3f3c00 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffff8887ca09d688 RDI: ffff888810fea510
RBP: 0000000000000010 R08: ffff8887ca09d688 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8887c26e8000
R13: ffffffffa05e9390 R14: 0000000000000000 R15: 0000000000000001
FS:  00007fcb5256f740(0000) GS:ffff888810e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 000000081e8fe000 CR4: 00000000003406e0
Call Trace:
 null_add_dev+0x534/0x71b [null_blk]
 nullb_device_power_store.cold.41+0x8/0x2e [null_blk]
 configfs_write_file+0xe6/0x150
 vfs_write+0xba/0x1e0
 ksys_write+0x5f/0xe0
 do_syscall_64+0x60/0x250
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x7fcb51c71840

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/block/null_blk_zoned.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
index 9c19f747f394..cc47606d8ffe 100644
--- a/drivers/block/null_blk_zoned.c
+++ b/drivers/block/null_blk_zoned.c
@@ -23,6 +23,10 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
 		pr_err("zone_size must be power-of-two\n");
 		return -EINVAL;
 	}
+	if (dev->zone_size > dev->size) {
+		pr_err("Zone size larger than device capacity\n");
+		return -EINVAL;
+	}
 
 	dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;
 	dev->nr_zones = dev_size >>
-- 
2.22.1

[PATCH 2/2] null_blk: don't allow discard for zoned mode

[Chaitanya Kulkarni]

Zoned block device specification do not define the behavior of
discard/trim command as this command is generally replaced by the reset
write pointer (zone reset) command. Emulate this in null_blk by making
zoned and discard options mutually exclusive.

Suggested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/block/null_blk_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 4f37b9fb28bb..6126f771ae99 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1561,6 +1561,13 @@ static void null_config_discard(struct nullb *nullb)
 {
 	if (nullb->dev->discard == false)
 		return;
+
+	if (nullb->dev->zoned) {
+		nullb->dev->discard = false;
+		pr_info("discard option is ignored in zoned mode\n");
+		return;
+	}
+
 	nullb->q->limits.discard_granularity = nullb->dev->blocksize;
 	nullb->q->limits.discard_alignment = nullb->dev->blocksize;
 	blk_queue_max_discard_sectors(nullb->q, UINT_MAX >> 9);
-- 
2.22.1

Re: [PATCH 1/2] null_blk: return error for invalid zone size

[Damien Le Moal]

On 2020/05/21 8:02, Chaitanya Kulkarni wrote:
> In null_init_zone_dev() check if the zone size is larger than device
> capacity, return error if needed.
> 
> This also fixes the following oops :-
> 
> null_blk: changed the number of conventional zones to 4294967295
> BUG: kernel NULL pointer dereference, address: 0000000000000010
> PGD 7d76c5067 P4D 7d76c5067 PUD 7d240c067 PMD 0
> Oops: 0002 [#1] SMP NOPTI
> CPU: 4 PID: 5508 Comm: nullbtests.sh Tainted: G OE 5.7.0-rc4lblk-fnext0
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e4
> RIP: 0010:null_init_zoned_dev+0x17a/0x27f [null_blk]
> RSP: 0018:ffffc90007007e00 EFLAGS: 00010246
> RAX: 0000000000000020 RBX: ffff8887fb3f3c00 RCX: 0000000000000007
> RDX: 0000000000000000 RSI: ffff8887ca09d688 RDI: ffff888810fea510
> RBP: 0000000000000010 R08: ffff8887ca09d688 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: ffff8887c26e8000
> R13: ffffffffa05e9390 R14: 0000000000000000 R15: 0000000000000001
> FS:  00007fcb5256f740(0000) GS:ffff888810e00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000010 CR3: 000000081e8fe000 CR4: 00000000003406e0
> Call Trace:
>  null_add_dev+0x534/0x71b [null_blk]
>  nullb_device_power_store.cold.41+0x8/0x2e [null_blk]
>  configfs_write_file+0xe6/0x150
>  vfs_write+0xba/0x1e0
>  ksys_write+0x5f/0xe0
>  do_syscall_64+0x60/0x250
>  entry_SYSCALL_64_after_hwframe+0x49/0xb3
> RIP: 0033:0x7fcb51c71840
> 
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

Looks good.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>

> ---
>  drivers/block/null_blk_zoned.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
> index 9c19f747f394..cc47606d8ffe 100644
> --- a/drivers/block/null_blk_zoned.c
> +++ b/drivers/block/null_blk_zoned.c
> @@ -23,6 +23,10 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
>  		pr_err("zone_size must be power-of-two\n");
>  		return -EINVAL;
>  	}
> +	if (dev->zone_size > dev->size) {
> +		pr_err("Zone size larger than device capacity\n");
> +		return -EINVAL;
> +	}
>  
>  	dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;
>  	dev->nr_zones = dev_size >>
> 


-- 
Damien Le Moal
Western Digital Research

Re: [PATCH 0/2]null_blk: small fixes for zoned mode

[Jens Axboe]

On 5/20/20 5:01 PM, Chaitanya Kulkarni wrote:
> Hi,
> 
> This is a small patch-series which fixes potential oops for zoned mode.
> Also, it disables the discard when nullb configured as zoned for
> membacked mode.

Applied for 5.7, thanks.

-- 
Jens Axboe