[Drbd-dev] [PATCH 23/27] block: add a bdev_max_discard_sectors helper
konishi.ryusuke at gmail.com
Wed Apr 6 19:28:15 CEST 2022
On Wed, Apr 6, 2022 at 11:05 PM Christoph Hellwig <hch at lst.de> wrote:
> Add a helper to query the number of sectors support per each discard bio
> based on the block device and use this helper to stop various places from
> poking into the request_queue to see if discard is supported and if so how
> much. This mirrors what is done e.g. for write zeroes as well.
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index 16e775bcf4a7c..7d510e4231713 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -829,9 +829,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name)
> - * Check if the underlying struct block_device request_queue supports
> - * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
> - * in ATA and we need to set TPE=1
> + * Check if the underlying struct block_device request_queue supports disard.
Here was a typo:
On Thu, Apr 7, 2022 at 12:19 AM Andreas Gruenbacher <agruenba at redhat.com> wrote:
> If I'm misreading things, could you please document that
> bdev_max_discard_sectors() != 0 implies that discard is supported?
I got the same impression. Checking the discard support with
bdev_max_discard_sectors() != 0 seems a bit unclear than before.
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