On Wed, 15 Jan 2025, Bart Van Assche wrote:
> Enable write pipelining if dm-linear is stacked on top of a driver that
> supports write pipelining.
Hi
What if you have multiple linear targets in a table? Then, the write order
would not be preserved.
How is write pipelining supposed to work with suspend/resume? dm doesn't
preserve the order of writes in case of suspend.
Mikulas
> Cc: Alasdair Kergon <agk@xxxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> drivers/md/dm-linear.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
> index 49fb0f684193..967fbf856abc 100644
> --- a/drivers/md/dm-linear.c
> +++ b/drivers/md/dm-linear.c
> @@ -148,6 +148,11 @@ static int linear_report_zones(struct dm_target *ti,
> #define linear_report_zones NULL
> #endif
>
> +static void linear_io_hints(struct dm_target *ti, struct queue_limits *limits)
> +{
> + limits->driver_preserves_write_order = true;
> +}
> +
> static int linear_iterate_devices(struct dm_target *ti,
> iterate_devices_callout_fn fn, void *data)
> {
> @@ -209,6 +214,7 @@ static struct target_type linear_target = {
> .map = linear_map,
> .status = linear_status,
> .prepare_ioctl = linear_prepare_ioctl,
> + .io_hints = linear_io_hints,
> .iterate_devices = linear_iterate_devices,
> .direct_access = linear_dax_direct_access,
> .dax_zero_page_range = linear_dax_zero_page_range,
>
