[dm-devel] [PATCH v2] dm: add support for DM_TARGET_NOWAIT for various targets

[JeffleXu]

Hi Mike,

I just tweaks the commit message in this v2 patch to make the purpose 
clearer,

while keep the code unstained.


Thanks,

Jeffle


On 11/13/20 10:05 AM, Jeffle Xu wrote:
> commit 021a24460dc2 ("block: add QUEUE_FLAG_NOWAIT") adds a new queue
> flag QUEUE_FLAG_NOWAIT to advertise if the bdev supports handling of
> REQ_NOWAIT or not. DM core supports this in commit 6abc49468eea ("dm:
> add support for REQ_NOWAIT and enable it for linear target"), in which
> only dm-linear is enabled.
>
> This patch also enables several dm-linear likely dm targets, the mapping
> algorithm of which is just simple remapping.
>
> Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
> ---
>   drivers/md/dm-stripe.c   | 2 +-
>   drivers/md/dm-switch.c   | 1 +
>   drivers/md/dm-unstripe.c | 1 +
>   drivers/md/dm-zero.c     | 1 +
>   4 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
> index 151d022b032d..df359d33cda8 100644
> --- a/drivers/md/dm-stripe.c
> +++ b/drivers/md/dm-stripe.c
> @@ -496,7 +496,7 @@ static void stripe_io_hints(struct dm_target *ti,
>   static struct target_type stripe_target = {
>   	.name   = "striped",
>   	.version = {1, 6, 0},
> -	.features = DM_TARGET_PASSES_INTEGRITY,
> +	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT,
>   	.module = THIS_MODULE,
>   	.ctr    = stripe_ctr,
>   	.dtr    = stripe_dtr,
> diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
> index bff4c7fa1cd2..262e2b0fd975 100644
> --- a/drivers/md/dm-switch.c
> +++ b/drivers/md/dm-switch.c
> @@ -550,6 +550,7 @@ static int switch_iterate_devices(struct dm_target *ti,
>   static struct target_type switch_target = {
>   	.name = "switch",
>   	.version = {1, 1, 0},
> +	.features = DM_TARGET_NOWAIT,
>   	.module = THIS_MODULE,
>   	.ctr = switch_ctr,
>   	.dtr = switch_dtr,
> diff --git a/drivers/md/dm-unstripe.c b/drivers/md/dm-unstripe.c
> index e673dacf6418..7357c1bd5863 100644
> --- a/drivers/md/dm-unstripe.c
> +++ b/drivers/md/dm-unstripe.c
> @@ -178,6 +178,7 @@ static void unstripe_io_hints(struct dm_target *ti,
>   static struct target_type unstripe_target = {
>   	.name = "unstriped",
>   	.version = {1, 1, 0},
> +	.features = DM_TARGET_NOWAIT,
>   	.module = THIS_MODULE,
>   	.ctr = unstripe_ctr,
>   	.dtr = unstripe_dtr,
> diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
> index b65ca8dcfbdc..faa1dbffc8b4 100644
> --- a/drivers/md/dm-zero.c
> +++ b/drivers/md/dm-zero.c
> @@ -59,6 +59,7 @@ static int zero_map(struct dm_target *ti, struct bio *bio)
>   static struct target_type zero_target = {
>   	.name   = "zero",
>   	.version = {1, 1, 0},
> +	.features = DM_TARGET_NOWAIT,
>   	.module = THIS_MODULE,
>   	.ctr    = zero_ctr,
>   	.map    = zero_map,

-- 
Thanks,
Jeffle