Ming Lei <ming....@canonical.com> writes:
> So that users can control if kernel aio is used to submit I/O.
How would a user know to choose aio or, um, /not/ aio? At the very
least, documentation is required for this. I'd rather see the option
disappear completely, though.
Cheers,
Jeff
>
> Signed-off-by: Ming Lei <ming....@canonical.com>
> ---
> drivers/block/loop.c | 33 +++++++++++++++++++++++++++++++++
> drivers/block/loop.h | 1 +
> 2 files changed, 34 insertions(+)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index d1f168b..47af456 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -659,6 +659,38 @@ static ssize_t loop_attr_partscan_show(struct
> loop_device *lo, char *buf)
> return sprintf(buf, "%s\n", partscan ? "1" : "0");
> }
>
> +static ssize_t loop_attr_do_show_use_aio(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct gendisk *disk = dev_to_disk(dev);
> + struct loop_device *lo = disk->private_data;
> +
> + return sprintf(buf, "%s\n", lo->use_aio ? "1" : "0");
> +}
> +
> +ssize_t loop_attr_do_store_use_aio(struct device *dev,
> + struct device_attribute *attr, const char *buf,
> + size_t count)
> +{
> + struct gendisk *disk = dev_to_disk(dev);
> + struct loop_device *lo = disk->private_data;
> + int err;
> + unsigned long v;
> +
> + err = kstrtoul(buf, 10, &v);
> + if (err < 0)
> + return err;
> + if (v)
> + lo->use_aio = true;
> + else
> + lo->use_aio = false;
> + return count;
> +}
> +
> +static struct device_attribute loop_attr_use_aio =
> + __ATTR(use_aio, S_IRUGO | S_IWUSR, loop_attr_do_show_use_aio,
> + loop_attr_do_store_use_aio);
> +
> LOOP_ATTR_RO(backing_file);
> LOOP_ATTR_RO(offset);
> LOOP_ATTR_RO(sizelimit);
> @@ -671,6 +703,7 @@ static struct attribute *loop_attrs[] = {
> &loop_attr_sizelimit.attr,
> &loop_attr_autoclear.attr,
> &loop_attr_partscan.attr,
> + &loop_attr_use_aio.attr,
> NULL,
> };
>
> diff --git a/drivers/block/loop.h b/drivers/block/loop.h
> index 301c27f..15049e9 100644
> --- a/drivers/block/loop.h
> +++ b/drivers/block/loop.h
> @@ -57,6 +57,7 @@ struct loop_device {
> struct list_head write_cmd_head;
> struct work_struct write_work;
> bool write_started;
> + bool use_aio;
> int lo_state;
> struct mutex lo_ctl_mutex;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
