On Wed, Jul 15, 2020 at 5:42 AM Yufen Yu <yuyufen@xxxxxxxxxx> wrote:
>
> Adding a new 'stripe_size' sysfs entry to set and show stripe_size.
> After that, we can adjust stripe_size by writing value into sysfs
> entry, likely, set stripe_size as 16KB:
>
> echo 16384 > /sys/block/md1/md/stripe_size
>
> Show current stripe_size value:
>
> cat /sys/block/md1/md/stripe_size
>
> stripe_size should not be bigger than PAGE_SIZE, and it requires to be
> multiple of 4096.
>
> Signed-off-by: Yufen Yu <yuyufen@xxxxxxxxxx>
For this patch, please consider the following changes:
1) use DEFAULT_STRIPE_SIZE instead of 4096;
2) make the sysfs entry read only for PAGE_SIZE == 4096
diff --git i/drivers/md/raid5.c w/drivers/md/raid5.c
index 735238425c7f3..320fc14bc628c 100644
--- i/drivers/md/raid5.c
+++ w/drivers/md/raid5.c
@@ -6532,6 +6532,8 @@ raid5_show_stripe_size(struct mddev *mddev, char *page)
return ret;
}
+#if PAGE_SIZE != DEFAULT_STRIPE_SIZE
+
static ssize_t
raid5_store_stripe_size(struct mddev *mddev, const char *page, size_t len)
{
@@ -6544,13 +6546,12 @@ raid5_store_stripe_size(struct mddev *mddev,
const char *page, size_t len)
return -EINVAL;
if (kstrtoul(page, 10, &new))
return -EINVAL;
+
/*
- * When PAGE_SZIE is 4096, we don't need to modify stripe_size.
- * And the value should not be bigger than PAGE_SIZE.
- * It requires to be multiple of 4096.
+ * The value should not be bigger than PAGE_SIZE. It requires to
+ * be multiple of DEFAULT_STRIPE_SIZE.
*/
- if (PAGE_SIZE == 4096 || new % 4096 != 0 ||
- new > PAGE_SIZE || new == 0)
+ if (new % DEFAULT_STRIPE_SIZE != 0 || new > PAGE_SIZE || new == 0)
return -EINVAL;
err = mddev_lock(mddev);
@@ -6612,6 +6613,15 @@ raid5_stripe_size = __ATTR(stripe_size, 0644,
raid5_show_stripe_size,
raid5_store_stripe_size);
+#else
+
+static struct md_sysfs_entry
+raid5_stripe_size = __ATTR(stripe_size, 0444,
+ raid5_show_stripe_size,
+ NULL);
+
+#endif /* PAGE_SIZE != DEFAULT_STRIPE_SIZE */
+
static ssize_t
raid5_show_preread_threshold(struct mddev *mddev, char *page)
{
