On 9 Dec 2022 15:23:27 +0100 Sergei Shtepa <sergei.shtepa@xxxxxxxxx>
> Provides the operation of block devices of snapshot images. Read and
> write operations are redirected to the regions of difference blocks for
> block device (struct diff_area).
>
> Signed-off-by: Sergei Shtepa <sergei.shtepa@xxxxxxxxx>
> ---
Thanks for your patchset.
> +static int snapimage_kthread_worker_fn(void *param)
> +{
> + struct snapimage *snapimage = param;
> + struct bio *bio;
> + int ret = 0;
> +
> + while (!kthread_should_stop()) {
> + bio = get_bio_from_queue(snapimage);
> + if (!bio) {
> + schedule_timeout_interruptible(HZ / 100);
> + continue;
> + }
Given the wake_up_process() below, s$HZ / 100$HZ * 1000$ to avoid
unnecessary wakeups [1].
And because of no signal handling added, use schedule_timeout_idle() instead.
[1] https://lore.kernel.org/lkml/20210419085027.761150-2-elver@xxxxxxxxxx/
> +
> + snapimage_process_bio(snapimage, bio);
> + }
> +
> + while ((bio = get_bio_from_queue(snapimage)))
> + snapimage_process_bio(snapimage, bio);
> +
> + return ret;
> +}
> +
> +static void snapimage_submit_bio(struct bio *bio)
> +{
> + struct snapimage *snapimage = bio->bi_bdev->bd_disk->private_data;
> + gfp_t gfp = GFP_NOIO;
> +
> + if (bio->bi_opf & REQ_NOWAIT)
> + gfp |= GFP_NOWAIT;
> + if (snapimage->is_ready) {
> + spin_lock(&snapimage->queue_lock);
> + bio_list_add(&snapimage->queue, bio);
> + spin_unlock(&snapimage->queue_lock);
> +
> + wake_up_process(snapimage->worker);
> + } else
> + bio_io_error(bio);
> +}
