md/raid5: factor out code for changing size of stripe cache.

Separate the actual 'change' code from the sysfs interface
so that it can eventually be called internally.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 26 insertions, 13 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 6a7a30113161..bd4067a70834 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4566,23 +4566,15 @@ raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
                 return 0;
 }
 
-static ssize_t
-raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
+int
+raid5_set_cache_size(mddev_t *mddev, int size)
 {
         raid5_conf_t *conf = mddev->private;
-        unsigned long new;
         int err;
 
-        if (len >= PAGE_SIZE)
+        if (size <= 16 || size > 32768)
                 return -EINVAL;
-        if (!conf)
-                return -ENODEV;
-
-        if (strict_strtoul(page, 10, &new))
-                return -EINVAL;
-        if (new <= 16 || new > 32768)
-                return -EINVAL;
-        while (new < conf->max_nr_stripes) {
+        while (size < conf->max_nr_stripes) {
                 if (drop_one_stripe(conf))
                         conf->max_nr_stripes--;
                 else
@@ -4591,11 +4583,32 @@ raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
         err = md_allow_write(mddev);
         if (err)
                 return err;
-        while (new > conf->max_nr_stripes) {
+        while (size > conf->max_nr_stripes) {
                 if (grow_one_stripe(conf))
                         conf->max_nr_stripes++;
                 else break;
         }
+        return 0;
+}
+EXPORT_SYMBOL(raid5_set_cache_size);
+
+static ssize_t
+raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len)
+{
+        raid5_conf_t *conf = mddev->private;
+        unsigned long new;
+        int err;
+
+        if (len >= PAGE_SIZE)
+                return -EINVAL;
+        if (!conf)
+                return -ENODEV;
+
+        if (strict_strtoul(page, 10, &new))
+                return -EINVAL;
+        err = raid5_set_cache_size(mddev, new);
+        if (err)
+                return err;
         return len;
 }