On 3/27/24 5:43 PM, Damien Le Moal wrote:
+ /*
+ * Initialize the zoen write plug with an extra reference so that
+ * it is not freed when the zone write plug becomes idle without
+ * the zone being full.
+ */
zoen -> zone
+static void disk_zone_wplugs_work(struct work_struct *work)
+{
+ struct gendisk *disk =
+ container_of(work, struct gendisk, zone_wplugs_work);
+ struct blk_zone_wplug *zwplug;
+ unsigned long flags;
+
+ spin_lock_irqsave(&disk->zone_wplugs_lock, flags);
+
+ while (!list_empty(&disk->zone_wplugs_err_list)) {
+ zwplug = list_first_entry(&disk->zone_wplugs_err_list,
+ struct blk_zone_wplug, link);
+ list_del_init(&zwplug->link);
+ blk_get_zone_wplug(zwplug);
+ spin_unlock_irqrestore(&disk->zone_wplugs_lock, flags);
+
+ disk_zone_wplug_handle_error(disk, zwplug);
+ disk_put_zone_wplug(zwplug);
+
+ spin_lock_irqsave(&disk->zone_wplugs_lock, flags);
+ }
+
+ spin_unlock_irqrestore(&disk->zone_wplugs_lock, flags);
+}
What is the maximum number of iterations the above while loop can
perform? I'm wondering whether a cond_resched() call should be added.
+
+ /* Wait for the zone write plugs to be RCU-freed. */
+ rcu_barrier();
+}
It is not clear to me why the above rcu_barrier() call is necessary? I'm
not aware of any other kernel code where kfree_rcu() is followed by an
rcu_barrier() call.
+static int disk_alloc_zone_resources(struct gendisk *disk,
+ unsigned int max_nr_zwplugs)
+{
+ unsigned int i;
+
+ disk->zone_wplugs_hash_bits =
+ min(ilog2(max_nr_zwplugs) + 1, BLK_ZONE_MAX_WPLUG_HASH_BITS);
If max_nr_zwplugs is a power of two, the above formula will result in a
hash table with a size that is twice the size of max_nr_zwplugs.
Shouldn't ilog2(max_nr_zwplugs) + 1 be changed into
ilog2(roundup_pow_of_two(max_nr_zwplugs))?
Otherwise this patch looks fine to me.
Thanks,
Bart.
