On 2022-07-28 05:07, Damien Le Moal wrote:
> On 7/28/22 01:22, Pankaj Raghav wrote:
>> Checking if a given sector is aligned to a zone is a common
>> operation that is performed for zoned devices. Add
>> bdev_is_zone_start helper to check for this instead of opencoding it
>
> The patch actually introduces bdev_is_zone_aligned(). I agree with Bart
> that bdev_is_zone_start() is a better name.
I have posted my rationale behind this change in my reply to Bart. Let
me know what you think.
>
<snip>
>> args->zone_sectors = zone->len;
>> - args->nr_zones = (capacity + zone->len - 1) >> ilog2(zone->len);
>> + args->nr_zones = div64_u64(capacity + zone->len - 1, zone->len);
>
> args->nr_zones = disk_zone_no(disk, capacity);
>
We are doing a round up with a division here mainly to take into account
the last unequal zone if present. disk_zone_no does just a division so
it won't account for the unequal last zone.
>> } else if (zone->start + args->zone_sectors < capacity) {
>> if (zone->len != args->zone_sectors) {
>> pr_warn("%s: Invalid zoned device with non constant zone size\n",
>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
>> index 85b832908f28..1be805223026 100644
>> --- a/include/linux/blkdev.h
>> +++ b/include/linux/blkdev.h
>> @@ -634,6 +634,11 @@ static inline bool queue_is_mq(struct request_queue *q)
>> return q->mq_ops;
>> }
>>
>> +static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
>> +{
>> + return bdev->bd_queue; /* this is never NULL */
>> +}
>> +
>> #ifdef CONFIG_PM
>> static inline enum rpm_status queue_rpm_status(struct request_queue *q)
>> {
>> @@ -665,6 +670,25 @@ static inline bool blk_queue_is_zoned(struct request_queue *q)
>> }
>> }
>>
>> +static inline bool bdev_is_zoned(struct block_device *bdev)
>> +{
>> + struct request_queue *q = bdev_get_queue(bdev);
>> +
>> + if (q)
>> + return blk_queue_is_zoned(q);
>> +
>> + return false;
>> +}
>> +
>> +static inline sector_t bdev_zone_sectors(struct block_device *bdev)
>> +{
>> + struct request_queue *q = bdev_get_queue(bdev);
>> +
>> + if (!blk_queue_is_zoned(q))
>> + return 0;
>> + return q->limits.chunk_sectors;
>> +}
>> +
>> #ifdef CONFIG_BLK_DEV_ZONED
>> static inline unsigned int disk_nr_zones(struct gendisk *disk)
>> {
>> @@ -684,6 +708,30 @@ static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
>> return div64_u64(sector, zone_sectors);
>> }
>>
>> +static inline sector_t bdev_offset_from_zone_start(struct block_device *bdev,
>> + sector_t sec)
>> +{
>> + sector_t zone_sectors = bdev_zone_sectors(bdev);
>> + u64 remainder = 0;
>> +
>> + if (!bdev_is_zoned(bdev))
>> + return 0;
>> +
>> + if (is_power_of_2(zone_sectors))
>> + return sec & (zone_sectors - 1);
>> +
>> + div64_u64_rem(sec, zone_sectors, &remainder);
>> + return remainder;
>> +}
>> +
>> +static inline bool bdev_is_zone_aligned(struct block_device *bdev, sector_t sec)
>> +{
>> + if (!bdev_is_zoned(bdev))
>> + return false;
>
> This is checked in bdev_offset_from_zone_start(). No need to add it again
> here.
>
bdev_offset_from_zone_start returns 0 if the device is not zoned, and
the below check will then return `true`. That is why I explicitly return
a false if the device is not zoned.
>> +
>> + return bdev_offset_from_zone_start(bdev, sec) == 0;
>> +}
>> +
>> static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t sector)
>> {
>> if (!blk_queue_is_zoned(disk->queue))
>> @@ -728,6 +776,18 @@ static inline unsigned int disk_zone_no(struct gendisk *disk, sector_t sector)
>> {
>> return 0;
>> }
>> +
>> +static inline sector_t bdev_offset_from_zone_start(struct block_device *bdev,
>> + sector_t sec)
>> +{
>> + return 0;
>> +}
>
> This one is not used when CONFIG_BLK_DEV_ZONED is not set. No need to
> define it.
>
Ok. I will remove it if it is not required.
>> +
>> +static inline bool bdev_is_zone_aligned(struct block_device *bdev, sector_t sec)
>> +{
>
