[PATCH 0/5] md: minor cleanups in md core and raid5/raid1/raid10

[PATCH 0/5] md: minor cleanups in md core and raid5/raid1/raid10

[Hiroshi Nishida]

A handful of small, no-functional-change cleanups noticed while reading
the md code:

 - drop an unused parameter from check_decay_read_errors();
 - use max() in raid5_calc_degraded();
 - make is_mddev_idle() take a bool init flag, matching the helper it
   forwards to;
 - declare a sector count as sector_t rather than int in status_resync();
 - rewrite a self-contradictory comment above the resync ETA math.

No behavioral change in any patch.  Built and functionally sanity-tested
(RAID5/RAID6 create, rebuild, scrub) on x86_64, including a run with KASAN
and lockdep enabled -- with concurrent /proc/mdstat polling to exercise
status_resync() -- and no reports.

Hiroshi Nishida (5):
  md/raid1,raid10: drop unused mddev arg from check_decay_read_errors()
  md/raid5: use max() in raid5_calc_degraded()
  md: make is_mddev_idle() take a bool init flag
  md: use sector_t for recovery_active in status_resync()
  md: clarify the resync ETA comment in status_resync()

 drivers/md/md.c       | 26 ++++++++++----------------
 drivers/md/raid1-10.c |  4 ++--
 drivers/md/raid5.c    |  4 +---
 3 files changed, 13 insertions(+), 21 deletions(-)

base-commit: 55b77337bdd088c77461588e5ec094421b89911b

-- 
2.43.0

[PATCH 1/5] md/raid1,raid10: drop unused mddev arg from check_decay_read_errors()

[Hiroshi Nishida]

check_decay_read_errors() only ever touches the passed rdev; the mddev
parameter has been unused. Remove it and update the sole caller in
exceed_read_errors().

No functional change.

Assisted-by: Claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Hiroshi Nishida <nishidafmly@gmail.com>
---
 drivers/md/raid1-10.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
index 56a56a4da4f8..edba52eb3116 100644
--- a/drivers/md/raid1-10.c
+++ b/drivers/md/raid1-10.c
@@ -171,7 +171,7 @@ static inline void raid1_prepare_flush_writes(struct mddev *mddev)
  * We halve the read error count for every hour that has elapsed
  * since the last recorded read error.
  */
-static inline void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
+static inline void check_decay_read_errors(struct md_rdev *rdev)
 {
 	long cur_time_mon;
 	unsigned long hours_since_last;
@@ -206,7 +206,7 @@ static inline bool exceed_read_errors(struct mddev *mddev, struct md_rdev *rdev)
 	int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
 	int read_errors;
 
-	check_decay_read_errors(mddev, rdev);
+	check_decay_read_errors(rdev);
 	read_errors =  atomic_inc_return(&rdev->read_errors);
 	if (read_errors > max_read_errors) {
 		pr_notice("md/"RAID_1_10_NAME":%s: %pg: Raid device exceeded read_error threshold [cur %d:max %d]\n",
-- 
2.43.0

[PATCH 2/5] md/raid5: use max() in raid5_calc_degraded()

[Hiroshi Nishida]

The tail of raid5_calc_degraded() open-codes a max of the two computed
degraded counts. Use max() for clarity.

No functional change.

Assisted-by: Claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Hiroshi Nishida <nishidafmly@gmail.com>
---
 drivers/md/raid5.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 0c5c9fb0606e..2b2aa4f2431c 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -741,9 +741,7 @@ int raid5_calc_degraded(struct r5conf *conf)
 			if (conf->raid_disks <= conf->previous_raid_disks)
 				degraded2++;
 	}
-	if (degraded2 > degraded)
-		return degraded2;
-	return degraded;
+	return max(degraded, degraded2);
 }
 
 static bool has_failed(struct r5conf *conf)
-- 
2.43.0

[PATCH 3/5] md: make is_mddev_idle() take a bool init flag

[Hiroshi Nishida]

is_mddev_idle() took an int init flag but passes it straight through to
is_rdev_holder_idle(), which already takes a bool. Make the types
consistent and update the two callers to pass true/false.

No functional change.

Assisted-by: Claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Hiroshi Nishida <nishidafmly@gmail.com>
---
 drivers/md/md.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index d1465bcd86c8..829b4a3f545b 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9219,7 +9219,7 @@ static bool is_rdev_holder_idle(struct md_rdev *rdev, bool init)
  *
  * Noted this checking rely on IO accounting is enabled.
  */
-static bool is_mddev_idle(struct mddev *mddev, int init)
+static bool is_mddev_idle(struct mddev *mddev, bool init)
 {
 	unsigned long last_events = mddev->normal_io_events;
 	struct gendisk *disk;
@@ -9771,7 +9771,7 @@ void md_do_sync(struct md_thread *thread)
 	pr_debug("md: using maximum available idle IO bandwidth (but not more than %d KB/sec) for %s.\n",
 		 speed_max(mddev), desc);
 
-	is_mddev_idle(mddev, 1); /* this initializes IO event counters */
+	is_mddev_idle(mddev, true); /* this initializes IO event counters */
 
 	io_sectors = 0;
 	for (m = 0; m < SYNC_MARKS; m++) {
@@ -9920,7 +9920,7 @@ void md_do_sync(struct md_thread *thread)
 				goto repeat;
 			}
 			if (!sync_io_within_limit(mddev) &&
-			    !is_mddev_idle(mddev, 0)) {
+			    !is_mddev_idle(mddev, false)) {
 				/*
 				 * Give other IO more of a chance.
 				 * The faster the devices, the less we wait.
-- 
2.43.0

[PATCH 4/5] md: use sector_t for recovery_active in status_resync()

[Hiroshi Nishida]

recovery_active holds a sector count read from the sector-typed atomic
mddev->recovery_active and is then combined with the sector_t values
curr_mark_cnt and resync_mark_cnt. Declaring it as a plain int needlessly
narrows it and mixes signedness into sector_t arithmetic; declare it
sector_t to match.

No functional change.

Assisted-by: Claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Hiroshi Nishida <nishidafmly@gmail.com>
---
 drivers/md/md.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 829b4a3f545b..0cd85cc92ed3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8816,8 +8816,8 @@ static int status_resync(struct seq_file *seq, struct mddev *mddev)
 {
 	sector_t max_sectors, resync, res;
 	unsigned long dt, db = 0;
-	sector_t rt, curr_mark_cnt, resync_mark_cnt;
-	int scale, recovery_active;
+	sector_t rt, curr_mark_cnt, resync_mark_cnt, recovery_active;
+	int scale;
 	unsigned int per_milli;
 
 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
-- 
2.43.0

[PATCH 5/5] md: clarify the resync ETA comment in status_resync()

[Hiroshi Nishida]

The comment above the remaining-time computation was self-contradictory:
it said the original algorithm was being kept but "is not really
necessary", then described that algorithm under an "Original algorithm:"
heading as if it had been replaced. The code still uses it. Rewrite the
comment to simply describe what the code does.

Comment only; no functional change.

Assisted-by: Claude:claude-opus-4-8 [Claude Code]
Signed-off-by: Hiroshi Nishida <nishidafmly@gmail.com>
---
 drivers/md/md.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0cd85cc92ed3..a5c0da0d1133 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8916,17 +8916,11 @@ static int status_resync(struct seq_file *seq, struct mddev *mddev)
 	 * db: blocks written from mark until now
 	 * rt: remaining time
 	 *
-	 * rt is a sector_t, which is always 64bit now. We are keeping
-	 * the original algorithm, but it is not really necessary.
-	 *
-	 * Original algorithm:
-	 *   So we divide before multiply in case it is 32bit and close
-	 *   to the limit.
-	 *   We scale the divisor (db) by 32 to avoid losing precision
-	 *   near the end of resync when the number of remaining sectors
-	 *   is close to 'db'.
-	 *   We then divide rt by 32 after multiplying by db to compensate.
-	 *   The '+1' avoids division by zero if db is very small.
+	 * rt is computed as (remaining sectors) * dt / db.  To keep precision
+	 * near the end of resync, when the remaining count is close to db, the
+	 * divisor db is scaled up by 32 before the divide and rt is scaled back
+	 * down by 32 afterwards.  The '+1' avoids division by zero when db is
+	 * very small.
 	 */
 	dt = ((jiffies - mddev->resync_mark) / HZ);
 	if (!dt) dt++;
-- 
2.43.0