Merge tag 'for-6.10/block-20240511' of git://git.kernel.dk/linux

Pull block updates from Jens Axboe:

 - Add a partscan attribute in sysfs, fixing an issue with systemd
   relying on an internal interface that went away.

 - Attempt #2 at making long running discards interruptible. The
   previous attempt went into 6.9, but we ended up mostly reverting it
   as it had issues.

 - Remove old ida_simple API in bcache

 - Support for zoned write plugging, greatly improving the performance
   on zoned devices.

 - Remove the old throttle low interface, which has been experimental
   since 2017 and never made it beyond that and isn't being used.

 - Remove page->index debugging checks in brd, as it hasn't caught
   anything and prepares us for removing in struct page.

 - MD pull request from Song

 - Don't schedule block workers on isolated CPUs

* tag 'for-6.10/block-20240511' of git://git.kernel.dk/linux: (84 commits)
  blk-throttle: delay initialization until configuration
  blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW
  block: fix that util can be greater than 100%
  block: support to account io_ticks precisely
  block: add plug while submitting IO
  bcache: fix variable length array abuse in btree_iter
  bcache: Remove usage of the deprecated ida_simple_xx() API
  md: Revert "md: Fix overflow in is_mddev_idle"
  blk-lib: check for kill signal in ioctl BLKDISCARD
  block: add a bio_await_chain helper
  block: add a blk_alloc_discard_bio helper
  block: add a bio_chain_and_submit helper
  block: move discard checks into the ioctl handler
  block: remove the discard_granularity check in __blkdev_issue_discard
  block/ioctl: prefer different overflow check
  null_blk: Fix the WARNING: modpost: missing MODULE_DESCRIPTION()
  block: fix and simplify blkdevparts= cmdline parsing
  block: refine the EOF check in blkdev_iomap_begin
  block: add a partscan sysfs attribute for disks
  block: add a disk_has_partscan helper
  ...

1 files changed, 19 insertions, 27 deletions

diff --git a/block/blk-throttle.h b/block/blk-throttle.h
index bffbc9cfc8ab..393c3d134b96 100644
--- a/block/blk-throttle.h
+++ b/block/blk-throttle.h
@@ -58,12 +58,6 @@ enum tg_state_flags {
 	THROTL_TG_CANCELING	= 1 << 2,	/* starts to cancel bio */
 };
 
-enum {
-	LIMIT_LOW,
-	LIMIT_MAX,
-	LIMIT_CNT,
-};
-
 struct throtl_grp {
 	/* must be the first member */
 	struct blkg_policy_data pd;
@@ -102,14 +96,14 @@ struct throtl_grp {
 	bool has_rules_iops[2];
 
 	/* internally used bytes per second rate limits */
-	uint64_t bps[2][LIMIT_CNT];
+	uint64_t bps[2];
 	/* user configured bps limits */
-	uint64_t bps_conf[2][LIMIT_CNT];
+	uint64_t bps_conf[2];
 
 	/* internally used IOPS limits */
-	unsigned int iops[2][LIMIT_CNT];
+	unsigned int iops[2];
 	/* user configured IOPS limits */
-	unsigned int iops_conf[2][LIMIT_CNT];
+	unsigned int iops_conf[2];
 
 	/* Number of bytes dispatched in current slice */
 	uint64_t bytes_disp[2];
@@ -132,22 +126,10 @@ struct throtl_grp {
 
 	unsigned long last_check_time;
 
-	unsigned long latency_target; /* us */
-	unsigned long latency_target_conf; /* us */
 	/* When did we start a new slice */
 	unsigned long slice_start[2];
 	unsigned long slice_end[2];
 
-	unsigned long last_finish_time; /* ns / 1024 */
-	unsigned long checked_last_finish_time; /* ns / 1024 */
-	unsigned long avg_idletime; /* ns / 1024 */
-	unsigned long idletime_threshold; /* us */
-	unsigned long idletime_threshold_conf; /* us */
-
-	unsigned int bio_cnt; /* total bios */
-	unsigned int bad_bio_cnt; /* bios exceeding latency threshold */
-	unsigned long bio_cnt_reset_time;
-
 	struct blkg_rwstat stat_bytes;
 	struct blkg_rwstat stat_ios;
 };
@@ -168,23 +150,33 @@ static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg)
  * Internal throttling interface
  */
 #ifndef CONFIG_BLK_DEV_THROTTLING
-static inline int blk_throtl_init(struct gendisk *disk) { return 0; }
 static inline void blk_throtl_exit(struct gendisk *disk) { }
-static inline void blk_throtl_register(struct gendisk *disk) { }
 static inline bool blk_throtl_bio(struct bio *bio) { return false; }
 static inline void blk_throtl_cancel_bios(struct gendisk *disk) { }
 #else /* CONFIG_BLK_DEV_THROTTLING */
-int blk_throtl_init(struct gendisk *disk);
 void blk_throtl_exit(struct gendisk *disk);
-void blk_throtl_register(struct gendisk *disk);
 bool __blk_throtl_bio(struct bio *bio);
 void blk_throtl_cancel_bios(struct gendisk *disk);
 
+static inline bool blk_throtl_activated(struct request_queue *q)
+{
+	return q->td != NULL;
+}
+
 static inline bool blk_should_throtl(struct bio *bio)
 {
-	struct throtl_grp *tg = blkg_to_tg(bio->bi_blkg);
+	struct throtl_grp *tg;
 	int rw = bio_data_dir(bio);
 
+	/*
+	 * This is called under bio_queue_enter(), and it's synchronized with
+	 * the activation of blk-throtl, which is protected by
+	 * blk_mq_freeze_queue().
+	 */
+	if (!blk_throtl_activated(bio->bi_bdev->bd_queue))
+		return false;
+
+	tg = blkg_to_tg(bio->bi_blkg);
 	if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) {
 		if (!bio_flagged(bio, BIO_CGROUP_ACCT)) {
 			bio_set_flag(bio, BIO_CGROUP_ACCT);