On 07/10/2020 08:24, Damien Le Moal wrote:
> On 2020/10/07 14:50, Christoph Hellwig wrote:
>>> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
>>> index 7dda709f3ccb..78817d7acb66 100644
>>> --- a/block/blk-sysfs.c
>>> +++ b/block/blk-sysfs.c
>>> @@ -246,6 +246,11 @@ queue_max_sectors_store(struct request_queue *q, const char
>>> *page, size_t count)
>>> spin_lock_irq(&q->queue_lock);
>>> q->limits.max_sectors = max_sectors_kb << 1;
>>> q->backing_dev_info->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
>>> +
>>> + q->limits.max_zone_append_sectors =
>>> + min(q->limits.max_sectors,
>>> + q->limits.max_hw_zone_append_sectors);
>>> +
>>> spin_unlock_irq(&q->queue_lock);
>>>
>>> return ret;
>>
>> Yes, this looks pretty sensible. I'm not even sure we need the field,
>> just do the min where we build the bio instead of introducing another
>> field that needs to be maintained.
>
> Indeed, that would be even simpler. But that would also mean repeating that min
> call for every user. So may be we should just add a simple helper
> queue_get_max_zone_append_sectors() ?
>
>
>
Like this?
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index cf80e61b4c5e..967cd76f16d4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1406,7 +1406,10 @@ static inline unsigned int queue_max_segment_size(const struct request_queue *q)
static inline unsigned int queue_max_zone_append_sectors(const struct request_queue *q)
{
- return q->limits.max_zone_append_sectors;
+
+ struct queue_limits *l = q->limits;
+
+ return min(l->max_zone_append_sectors, l->max_sectors);
}
static inline unsigned queue_logical_block_size(const struct request_queue *q)
That's indeed much simpler, we'd just need to take precaution everyone's using
queue_max_zone_append_sectors() and isn't directly poking into the queue_limits.
