[PATCH v2 1/8] md: pass a queue_limits down to ->hot_add_disk()
From: Jack Wang <jinpu.wang@ionos.com>
Date: 2026-09-10 08:11:19
Also in:
dm-devel, linux-raid, lkml
Subsystem:
device-mapper (lvm), software raid (multiple disks) support, the rest · Maintainers:
Alasdair Kergon, Mike Snitzer, Mikulas Patocka, Benjamin Marzinski, Song Liu, Yu Kuai, Linus Torvalds
From: Jack Wang <jinpu.wang@cloud.ionos.com> Adding a leg stacks its queue limits, which mddev_stack_new_rdev() does by taking q->limits_lock itself. Callers holding reconfig_mutex or a suspended array cannot allow that, and must own the update instead. Give ->hot_add_disk(), remove_and_add_spares() and md_choose_sync_action() a struct queue_limits argument with three states: an update to stack into, NULL to let the personality take the lock as before, or MDDEV_STACK_SKIP to add the leg without touching the limits, for callers that can do neither. mddev_stack_rdev_into() stacks into a caller-owned update without the lock. Every caller still passes NULL and nothing passes the sentinel yet, so there is no functional change; the users follow. Assisted-by: LLM Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> --- drivers/md/dm-raid.c | 2 +- drivers/md/md-linear.c | 28 ++++++++++++++---- drivers/md/md.c | 66 ++++++++++++++++++++++++++++++++---------- drivers/md/md.h | 11 ++++++- drivers/md/raid1.c | 10 +++++-- drivers/md/raid10.c | 19 +++++++++--- drivers/md/raid5.c | 5 ++-- 7 files changed, 110 insertions(+), 31 deletions(-)
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 8f5a5e1342a9..21a1922bee4f 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c@@ -3923,7 +3923,7 @@ static void attempt_restore_of_faulty_devices(struct raid_set *rs) clear_bit(Faulty, &r->flags); clear_bit(WriteErrorSeen, &r->flags); - if (mddev->pers->hot_add_disk(mddev, r)) { + if (mddev->pers->hot_add_disk(mddev, r, NULL)) { /* Failed to revive this device, try next */ r->raid_disk = r->saved_raid_disk = -1; r->flags = flags;
diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
index 73b367b61b87..da82c313d459 100644
--- a/drivers/md/md-linear.c
+++ b/drivers/md/md-linear.c@@ -65,11 +65,16 @@ static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disk return array_sectors; } -static int linear_set_limits(struct mddev *mddev) +static int linear_set_limits(struct mddev *mddev, + struct queue_limits *caller_lim) { struct queue_limits lim; int err; + /* the caller can neither stack nor take q->limits_lock */ + if (caller_lim == MDDEV_STACK_SKIP) + return 0; + md_init_stacking_limits(&lim); lim.features |= BLK_FEAT_NOWAIT; lim.max_hw_sectors = mddev->chunk_sectors;
@@ -82,10 +87,20 @@ static int linear_set_limits(struct mddev *mddev) if (err) return err; + /* + * The caller owns an update and commits it itself; taking + * q->limits_lock here would take it a second time. + */ + if (caller_lim) { + *caller_lim = lim; + return 0; + } + return queue_limits_set(mddev->gendisk->queue, &lim); } -static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) +static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks, + struct queue_limits *lim) { struct linear_conf *conf; struct md_rdev *rdev;
@@ -151,7 +166,7 @@ static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks) conf->disks[i].rdev->sectors; if (!mddev_is_dm(mddev)) { - ret = linear_set_limits(mddev); + ret = linear_set_limits(mddev, lim); if (ret) goto out; }
@@ -171,7 +186,7 @@ static int linear_run(struct mddev *mddev) if (md_check_no_bitmap(mddev)) return -EINVAL; - conf = linear_conf(mddev, mddev->raid_disks); + conf = linear_conf(mddev, mddev->raid_disks, NULL); if (IS_ERR(conf)) return PTR_ERR(conf);
@@ -186,7 +201,8 @@ static int linear_run(struct mddev *mddev) return ret; } -static int linear_add(struct mddev *mddev, struct md_rdev *rdev) +static int linear_add(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim) { /* Adding a drive to a linear array allows the array to grow. * It is permitted if the new drive has a matching superblock
@@ -204,7 +220,7 @@ static int linear_add(struct mddev *mddev, struct md_rdev *rdev) rdev->raid_disk = rdev->saved_raid_disk; rdev->saved_raid_disk = -1; - newconf = linear_conf(mddev, mddev->raid_disks + 1); + newconf = linear_conf(mddev, mddev->raid_disks + 1, lim); if (IS_ERR(newconf)) return PTR_ERR(newconf);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 680b34a63cb3..28fc903ffeea 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c@@ -94,8 +94,8 @@ static DECLARE_WAIT_QUEUE_HEAD(resync_wait); */ static struct workqueue_struct *md_misc_wq; -static int remove_and_add_spares(struct mddev *mddev, - struct md_rdev *this); +static int remove_and_add_spares(struct mddev *mddev, struct md_rdev *this, + struct queue_limits *lim); static void mddev_detach(struct mddev *mddev); static void export_rdev(struct md_rdev *rdev); static void md_wakeup_thread_directly(struct md_thread __rcu **thread);
@@ -2994,7 +2994,7 @@ static int add_bound_rdev(struct md_rdev *rdev) */ super_types[mddev->major_version]. validate_super(mddev, NULL/*freshest*/, rdev); - err = mddev->pers->hot_add_disk(mddev, rdev); + err = mddev->pers->hot_add_disk(mddev, rdev, NULL); if (err) { md_kick_rdev_from_array(rdev); return err;
@@ -3110,7 +3110,7 @@ state_store(struct md_rdev *rdev, const char *buf, size_t len) } else if (cmd_match(buf, "remove")) { if (rdev->mddev->pers) { clear_bit(Blocked, &rdev->flags); - remove_and_add_spares(rdev->mddev, rdev); + remove_and_add_spares(rdev->mddev, rdev, NULL); } if (rdev->raid_disk >= 0) err = -EBUSY;
@@ -3314,7 +3314,7 @@ slot_store(struct md_rdev *rdev, const char *buf, size_t len) if (rdev->mddev->pers->hot_remove_disk == NULL) return -EINVAL; clear_bit(Blocked, &rdev->flags); - remove_and_add_spares(rdev->mddev, rdev); + remove_and_add_spares(rdev->mddev, rdev, NULL); if (rdev->raid_disk >= 0) return -EBUSY; set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
@@ -3344,7 +3344,8 @@ slot_store(struct md_rdev *rdev, const char *buf, size_t len) rdev->saved_raid_disk = -1; clear_bit(In_sync, &rdev->flags); clear_bit(Bitmap_sync, &rdev->flags); - err = rdev->mddev->pers->hot_add_disk(rdev->mddev, rdev); + err = rdev->mddev->pers->hot_add_disk(rdev->mddev, rdev, + NULL); if (err) { rdev->raid_disk = -1; return err;
@@ -6275,6 +6276,40 @@ int mddev_stack_new_rdev(struct mddev *mddev, struct md_rdev *rdev) } EXPORT_SYMBOL_GPL(mddev_stack_new_rdev); +/* + * Stack a new rdev into limits the caller already holds limits_lock for and + * will commit itself. Used from paths that must take limits_lock before + * quiescing the array, see md_start_sync(). + */ +int mddev_stack_rdev_into(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim) +{ + struct queue_limits tmp = *lim; + + if (mddev_is_dm(mddev)) + return 0; + + if (queue_logical_block_size(rdev->bdev->bd_disk->queue) > + queue_logical_block_size(mddev->gendisk->queue)) { + pr_err("%s: incompatible logical_block_size, can not add\n", + mdname(mddev)); + return -EINVAL; + } + + queue_limits_stack_bdev(&tmp, rdev->bdev, rdev->data_offset, + mddev->gendisk->disk_name); + + if (!queue_limits_stack_integrity_bdev(&tmp, rdev->bdev)) { + pr_err("%s: incompatible integrity profile for %pg\n", + mdname(mddev), rdev->bdev); + return -ENXIO; + } + + *lim = tmp; + return 0; +} +EXPORT_SYMBOL_GPL(mddev_stack_rdev_into); + /* update the optimal I/O size after a reshape */ void mddev_update_io_opt(struct mddev *mddev, unsigned int nr_stripes) {
@@ -7706,7 +7741,7 @@ static int hot_remove_disk(struct mddev *mddev, dev_t dev) goto kick_rdev; clear_bit(Blocked, &rdev->flags); - remove_and_add_spares(mddev, rdev); + remove_and_add_spares(mddev, rdev, NULL); if (rdev->raid_disk >= 0) goto busy;
@@ -10167,8 +10202,8 @@ static int remove_spares(struct mddev *mddev, struct md_rdev *this) return removed; } -static int remove_and_add_spares(struct mddev *mddev, - struct md_rdev *this) +static int remove_and_add_spares(struct mddev *mddev, struct md_rdev *this, + struct queue_limits *lim) { struct md_rdev *rdev; int spares = 0;
@@ -10191,7 +10226,7 @@ static int remove_and_add_spares(struct mddev *mddev, continue; if (!test_bit(Journal, &rdev->flags)) rdev->recovery_offset = 0; - if (mddev->pers->hot_add_disk(mddev, rdev) == 0) { + if (mddev->pers->hot_add_disk(mddev, rdev, lim) == 0) { /* failure here is OK */ sysfs_link_rdev(mddev, rdev); if (!test_bit(Journal, &rdev->flags))
@@ -10206,7 +10241,8 @@ static int remove_and_add_spares(struct mddev *mddev, return spares; } -static bool md_choose_sync_action(struct mddev *mddev, int *spares) +static bool md_choose_sync_action(struct mddev *mddev, int *spares, + struct queue_limits *lim) { /* Check if reshape is in progress first. */ if (mddev->reshape_position != MaxSector) {
@@ -10234,7 +10270,7 @@ static bool md_choose_sync_action(struct mddev *mddev, int *spares) * also removed and re-added, to allow the personality to fail the * re-add. */ - *spares = remove_and_add_spares(mddev, NULL); + *spares = remove_and_add_spares(mddev, NULL, lim); if (*spares || test_bit(MD_RECOVERY_LAZY_RECOVER, &mddev->recovery)) { clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
@@ -10294,11 +10330,11 @@ static void md_start_sync(struct work_struct *ws) * As we only add devices that are already in-sync, we can * activate the spares immediately. */ - remove_and_add_spares(mddev, NULL); + remove_and_add_spares(mddev, NULL, NULL); goto not_running; } - if (!md_choose_sync_action(mddev, &spares)) + if (!md_choose_sync_action(mddev, &spares, NULL)) goto not_running; if (!mddev->pers->sync_request)
@@ -10849,7 +10885,7 @@ static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev) rdev2->saved_raid_disk = -1; else rdev2->saved_raid_disk = role; - ret = remove_and_add_spares(mddev, rdev2); + ret = remove_and_add_spares(mddev, rdev2, NULL); pr_info("Activated spare: %pg\n", rdev2->bdev); /* wakeup mddev->thread here, so array could
diff --git a/drivers/md/md.h b/drivers/md/md.h
index b6d2e8929a0f..ebdd57677062 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h@@ -765,7 +765,8 @@ struct md_personality * if appropriate, and should abort recovery if needed */ void (*error_handler)(struct mddev *mddev, struct md_rdev *rdev); - int (*hot_add_disk) (struct mddev *mddev, struct md_rdev *rdev); + int (*hot_add_disk)(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim); int (*hot_remove_disk) (struct mddev *mddev, struct md_rdev *rdev); int (*spare_active) (struct mddev *mddev); sector_t (*sync_request)(struct mddev *mddev, sector_t sector_nr,
@@ -1047,6 +1048,14 @@ int do_md_run(struct mddev *mddev); int mddev_stack_rdev_limits(struct mddev *mddev, struct queue_limits *lim, unsigned int flags); int mddev_stack_new_rdev(struct mddev *mddev, struct md_rdev *rdev); +int mddev_stack_rdev_into(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim); +/* + * Sentinel for the queue_limits argument of ->hot_add_disk(). The caller has + * no update to stack into and must not take q->limits_lock itself, so the leg + * is added with the array's current limits. + */ +#define MDDEV_STACK_SKIP ((struct queue_limits *)ERR_PTR(-EAGAIN)) void mddev_update_io_opt(struct mddev *mddev, unsigned int nr_stripes); extern const struct block_device_operations md_fops;
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index f0646fb24371..78effcac138d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c@@ -1898,7 +1898,8 @@ static bool raid1_remove_conf(struct r1conf *conf, int disk) return true; } -static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev) +static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim) { struct r1conf *conf = mddev->private; int err = -EEXIST;
@@ -1923,7 +1924,12 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev) for (mirror = first; mirror <= last; mirror++) { p = conf->mirrors + mirror; if (!p->rdev) { - err = mddev_stack_new_rdev(mddev, rdev); + if (lim == MDDEV_STACK_SKIP) + err = 0; + else if (lim) + err = mddev_stack_rdev_into(mddev, rdev, lim); + else + err = mddev_stack_new_rdev(mddev, rdev); if (err) return err;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 1093c798d9dd..222bd7badcff 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c@@ -2095,7 +2095,8 @@ static int raid10_spare_active(struct mddev *mddev) return count; } -static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev) +static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim) { struct r10conf *conf = mddev->private; int err = -EEXIST;
@@ -2130,7 +2131,12 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev) continue; } - err = mddev_stack_new_rdev(mddev, rdev); + if (lim == MDDEV_STACK_SKIP) + err = 0; + else if (lim) + err = mddev_stack_rdev_into(mddev, rdev, lim); + else + err = mddev_stack_new_rdev(mddev, rdev); if (err) return err; p->head_position = 0;
@@ -2147,7 +2153,12 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev) clear_bit(In_sync, &rdev->flags); set_bit(Replacement, &rdev->flags); rdev->raid_disk = repl_slot; - err = mddev_stack_new_rdev(mddev, rdev); + if (lim == MDDEV_STACK_SKIP) + err = 0; + else if (lim) + err = mddev_stack_rdev_into(mddev, rdev, lim); + else + err = mddev_stack_new_rdev(mddev, rdev); if (err) return err; conf->fullsync = 1;
@@ -4484,7 +4495,7 @@ static int raid10_start_reshape(struct mddev *mddev) rdev_for_each(rdev, mddev) if (rdev->raid_disk < 0 && !test_bit(Faulty, &rdev->flags)) { - if (raid10_add_disk(mddev, rdev) == 0) { + if (raid10_add_disk(mddev, rdev, NULL) == 0) { if (rdev->raid_disk >= conf->prev.raid_disks) set_bit(In_sync, &rdev->flags);
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b91545ce090d..0ec555ada64a 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c@@ -8441,7 +8441,8 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev) return err; } -static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) +static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev, + struct queue_limits *lim) { struct r5conf *conf = mddev->private; int ret, err = -EEXIST;
@@ -8728,7 +8729,7 @@ static int raid5_start_reshape(struct mddev *mddev) rdev_for_each(rdev, mddev) if (rdev->raid_disk < 0 && !test_bit(Faulty, &rdev->flags)) { - if (raid5_add_disk(mddev, rdev) == 0) { + if (raid5_add_disk(mddev, rdev, NULL) == 0) { if (rdev->raid_disk >= conf->previous_raid_disks) set_bit(In_sync, &rdev->flags);
--
2.43.0