Messages in this thread Patch in this message | | | From | Ming Lei <> | Subject | [PATCH v2 3/4] block: loop: introduce 'use_aio' sysfs file | Date | Tue, 13 Jan 2015 23:44:47 +0800 |
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So that users can control if kernel aio is used to submit I/O.
Signed-off-by: Ming Lei <ming.lei@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; -- 1.7.9.5
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