diff mbox series

[v4,03/11] scsi: sd_zbc: Fix sd_zbc_check_zones() error checks

Message ID 20181012100850.23316-4-damien.lemoal@wdc.com (mailing list archive)
State Not Applicable
Headers show
Series Zoned block device support improvements | expand

Commit Message

Damien Le Moal Oct. 12, 2018, 10:08 a.m. UTC
The unsigned 32 bits overflow check for the zone size value is already
done within sd_zbc_check_zones() with the test:

} else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {

so there is no need to check again for an out of range value in
sd_zbc_read_zones(). Simplify the code and fix sd_zbc_check_zones()
error return to -EFBIG instead of -ENODEV if the zone size is too large.
Change the return type of sd_zbc_check_zones() to an int for the error
code and return the zone size (zone_blocks) through a u32 pointer to
avoid overflowing the signed 32 return value.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 drivers/scsi/sd_zbc.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

Comments

Hannes Reinecke Oct. 12, 2018, 10:23 a.m. UTC | #1
On 10/12/18 12:08 PM, Damien Le Moal wrote:
> The unsigned 32 bits overflow check for the zone size value is already
> done within sd_zbc_check_zones() with the test:
> 
> } else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
> 
> so there is no need to check again for an out of range value in
> sd_zbc_read_zones(). Simplify the code and fix sd_zbc_check_zones()
> error return to -EFBIG instead of -ENODEV if the zone size is too large.
> Change the return type of sd_zbc_check_zones() to an int for the error
> code and return the zone size (zone_blocks) through a u32 pointer to
> avoid overflowing the signed 32 return value.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
>   drivers/scsi/sd_zbc.c | 19 ++++++++-----------
>   1 file changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
> index ca73c46931c0..0678e1e108b0 100644
> --- a/drivers/scsi/sd_zbc.c
> +++ b/drivers/scsi/sd_zbc.c
> @@ -373,7 +373,7 @@ static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
>    * Returns the zone size in number of blocks upon success or an error code
>    * upon failure.
>    */
> -static s64 sd_zbc_check_zones(struct scsi_disk *sdkp)
> +static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
>   {
>   	u64 zone_blocks = 0;
>   	sector_t max_lba, block = 0;

Actually I thought to just change the 's32' to 'int', and not adding 
another parameter; but anyway.

Reviewed-by: Hannes Reinecke <hare@suse.com>

Hannes
Damien Le Moal Oct. 12, 2018, 11:41 a.m. UTC | #2
On 2018/10/12 19:23, Hannes Reinecke wrote:
> On 10/12/18 12:08 PM, Damien Le Moal wrote:
>> The unsigned 32 bits overflow check for the zone size value is already
>> done within sd_zbc_check_zones() with the test:
>>
>> } else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
>>
>> so there is no need to check again for an out of range value in
>> sd_zbc_read_zones(). Simplify the code and fix sd_zbc_check_zones()
>> error return to -EFBIG instead of -ENODEV if the zone size is too large.
>> Change the return type of sd_zbc_check_zones() to an int for the error
>> code and return the zone size (zone_blocks) through a u32 pointer to
>> avoid overflowing the signed 32 return value.
>>
>> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
>> ---
>>   drivers/scsi/sd_zbc.c | 19 ++++++++-----------
>>   1 file changed, 8 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
>> index ca73c46931c0..0678e1e108b0 100644
>> --- a/drivers/scsi/sd_zbc.c
>> +++ b/drivers/scsi/sd_zbc.c
>> @@ -373,7 +373,7 @@ static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
>>    * Returns the zone size in number of blocks upon success or an error code
>>    * upon failure.
>>    */
>> -static s64 sd_zbc_check_zones(struct scsi_disk *sdkp)
>> +static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
>>   {
>>   	u64 zone_blocks = 0;
>>   	sector_t max_lba, block = 0;
> 
> Actually I thought to just change the 's32' to 'int', and not adding 
> another parameter; but anyway.

Yes, I understood that. But since chunk_sectors is unsigned int, zone_blocks has
to be too and so returning that through an int would be asking for troubles. If
we ever have see a drive with a 2G LBA zone size that is :)
I thought it was cleaner this way.

> 
> Reviewed-by: Hannes Reinecke <hare@suse.com>

Thanks !

> 
> Hannes
>
Martin K. Petersen Oct. 16, 2018, 4:51 a.m. UTC | #3
Damien,

> The unsigned 32 bits overflow check for the zone size value is already
> done within sd_zbc_check_zones() with the test:
>
> } else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
>
> so there is no need to check again for an out of range value in
> sd_zbc_read_zones(). Simplify the code and fix sd_zbc_check_zones()
> error return to -EFBIG instead of -ENODEV if the zone size is too large.
> Change the return type of sd_zbc_check_zones() to an int for the error
> code and return the zone size (zone_blocks) through a u32 pointer to
> avoid overflowing the signed 32 return value.

Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Christoph Hellwig Oct. 17, 2018, 7:21 a.m. UTC | #4
> @@ -687,12 +688,8 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
>  	 * Check zone size: only devices with a constant zone size (except
>  	 * an eventual last runt zone) that is a power of 2 are supported.
>  	 */
> -	zone_blocks = sd_zbc_check_zones(sdkp);
> -	ret = -EFBIG;
> -	if (zone_blocks != (u32)zone_blocks)
> -		goto err;
> -	ret = zone_blocks;
> -	if (ret < 0)
> +	ret = sd_zbc_check_zones(sdkp, &zone_blocks);
> +	if (ret != 0)

This coud be simplified to

	if (ret)

or just keep the old

	if (ret < 0)

which would still work.

Otherwise looks fine:

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index ca73c46931c0..0678e1e108b0 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -373,7 +373,7 @@  static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
  * Returns the zone size in number of blocks upon success or an error code
  * upon failure.
  */
-static s64 sd_zbc_check_zones(struct scsi_disk *sdkp)
+static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
 {
 	u64 zone_blocks = 0;
 	sector_t max_lba, block = 0;
@@ -381,7 +381,7 @@  static s64 sd_zbc_check_zones(struct scsi_disk *sdkp)
 	unsigned char *rec;
 	unsigned int buf_len;
 	unsigned int list_length;
-	s64 ret;
+	int ret;
 	u8 same;
 
 	/* Get a buffer */
@@ -472,9 +472,10 @@  static s64 sd_zbc_check_zones(struct scsi_disk *sdkp)
 		if (sdkp->first_scan)
 			sd_printk(KERN_NOTICE, sdkp,
 				  "Zone size too large\n");
-		ret = -ENODEV;
+		ret = -EFBIG;
 	} else {
-		ret = zone_blocks;
+		*zblocks = zone_blocks;
+		ret = 0;
 	}
 
 out_free:
@@ -668,7 +669,7 @@  static int sd_zbc_setup(struct scsi_disk *sdkp, u32 zone_blocks)
 
 int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 {
-	int64_t zone_blocks;
+	u32 zone_blocks;
 	int ret;
 
 	if (!sd_is_zoned(sdkp))
@@ -687,12 +688,8 @@  int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 	 * Check zone size: only devices with a constant zone size (except
 	 * an eventual last runt zone) that is a power of 2 are supported.
 	 */
-	zone_blocks = sd_zbc_check_zones(sdkp);
-	ret = -EFBIG;
-	if (zone_blocks != (u32)zone_blocks)
-		goto err;
-	ret = zone_blocks;
-	if (ret < 0)
+	ret = sd_zbc_check_zones(sdkp, &zone_blocks);
+	if (ret != 0)
 		goto err;
 
 	/* The drive satisfies the kernel restrictions: set it up */