Previously, we called rdev_init_wb to avoid potential data
inconsistency when array is created.
Now, we need to call the function and create mempool if a
device is added or just be flaged as "writemostly". So
mddev_create_wb_pool is introduced and called accordingly.
And for safety reason, we mark implicit GFP_NOIO allocation
scope for create mempool during mddev_suspend/mddev_resume.
And mempool should be removed conversely after remove a
member device or its's "writemostly" flag, which is done
by call mddev_destroy_wb_pool.
Reviewed-by: NeilBrown <neilb@xxxxxxxx>
Signed-off-by: Guoqing Jiang <gqjiang@xxxxxxxx>
---
drivers/md/md.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/md/md.h | 2 ++
2 files changed, 67 insertions(+)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3f816e4d4dd8..7bab12a8d237 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -44,6 +44,7 @@
*/
+#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/kthread.h>
#include <linux/blkdev.h>
@@ -144,6 +145,64 @@ static int rdev_init_wb(struct md_rdev *rdev)
return 1;
}
+/*
+ * Create wb_info_pool if rdev is the first multi-queue device flaged
+ * with writemostly, also write-behind mode is enabled.
+ */
+void mddev_create_wb_pool(struct mddev *mddev, struct md_rdev *rdev,
+ bool is_suspend)
+{
+ if (mddev->bitmap_info.max_write_behind == 0)
+ return;
+
+ if (!test_bit(WriteMostly, &rdev->flags) || !rdev_init_wb(rdev))
+ return;
+
+ if (mddev->wb_info_pool == NULL) {
+ unsigned int noio_flag;
+
+ if (!is_suspend)
+ mddev_suspend(mddev);
+ noio_flag = memalloc_noio_save();
+ mddev->wb_info_pool = mempool_create_kmalloc_pool(NR_WB_INFOS,
+ sizeof(struct wb_info));
+ memalloc_noio_restore(noio_flag);
+ if (!mddev->wb_info_pool)
+ pr_err("can't alloc memory pool for writemostly\n");
+ if (!is_suspend)
+ mddev_resume(mddev);
+ }
+}
+EXPORT_SYMBOL_GPL(mddev_create_wb_pool);
+
+/*
+ * destroy wb_info_pool if rdev is the last device flaged with WBCollisionCheck.
+ */
+static void mddev_destroy_wb_pool(struct mddev *mddev, struct md_rdev *rdev)
+{
+ if (!test_and_clear_bit(WBCollisionCheck, &rdev->flags))
+ return;
+
+ if (mddev->wb_info_pool) {
+ struct md_rdev *temp;
+ int num = 0;
+
+ /*
+ * Check if other rdevs need wb_info_pool.
+ */
+ rdev_for_each(temp, mddev)
+ if (temp != rdev &&
+ test_bit(WBCollisionCheck, &temp->flags))
+ num++;
+ if (!num) {
+ mddev_suspend(rdev->mddev);
+ mempool_destroy(mddev->wb_info_pool);
+ mddev->wb_info_pool = NULL;
+ mddev_resume(rdev->mddev);
+ }
+ }
+}
+
static struct ctl_table_header *raid_table_header;
static struct ctl_table raid_table[] = {
@@ -2230,6 +2289,9 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
rdev->mddev = mddev;
pr_debug("md: bind<%s>\n", b);
+ if (mddev->raid_disks)
+ mddev_create_wb_pool(mddev, rdev, false);
+
if ((err = kobject_add(&rdev->kobj, &mddev->kobj, "dev-%s", b)))
goto fail;
@@ -2266,6 +2328,7 @@ static void unbind_rdev_from_array(struct md_rdev *rdev)
bd_unlink_disk_holder(rdev->bdev, rdev->mddev->gendisk);
list_del_rcu(&rdev->same_set);
pr_debug("md: unbind<%s>\n", bdevname(rdev->bdev,b));
+ mddev_destroy_wb_pool(rdev->mddev, rdev);
rdev->mddev = NULL;
sysfs_remove_link(&rdev->kobj, "block");
sysfs_put(rdev->sysfs_state);
@@ -2778,8 +2841,10 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len)
}
} else if (cmd_match(buf, "writemostly")) {
set_bit(WriteMostly, &rdev->flags);
+ mddev_create_wb_pool(rdev->mddev, rdev, false);
err = 0;
} else if (cmd_match(buf, "-writemostly")) {
+ mddev_destroy_wb_pool(rdev->mddev, rdev);
clear_bit(WriteMostly, &rdev->flags);
err = 0;
} else if (cmd_match(buf, "blocked")) {
diff --git a/drivers/md/md.h b/drivers/md/md.h
index ce9eb6db0538..fcb6cce5a459 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -737,6 +737,8 @@ extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
extern void md_reload_sb(struct mddev *mddev, int raid_disk);
extern void md_update_sb(struct mddev *mddev, int force);
extern void md_kick_rdev_from_array(struct md_rdev * rdev);
+extern void mddev_create_wb_pool(struct mddev *mddev, struct md_rdev *rdev,
+ bool is_suspend);
struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
struct md_rdev *md_find_rdev_rcu(struct mddev *mddev, dev_t dev);
--
2.12.3
