/* SPDX-License-Identifier: GPL-2.0 */#ifndef _RAID1_H#define _RAID1_H /* * each barrier unit size is 64MB fow now * note: it must be larger than RESYNC_DEPTH */#define BARRIER_UNIT_SECTOR_BITS	17#define BARRIER_UNIT_SECTOR_SIZE	(1<<17)/* * In struct r1conf, the following members are related to I/O barrier * buckets, *	atomic_t	*nr_pending; *	atomic_t	*nr_waiting; *	atomic_t	*nr_queued; *	atomic_t	*barrier; * Each of them points to array of atomic_t variables, each array is * designed to have BARRIER_BUCKETS_NR elements and occupy a single * memory page. The data width of atomic_t variables is 4 bytes, equal * to 1<<(ilog2(sizeof(atomic_t))), BARRIER_BUCKETS_NR_BITS is defined * as (PAGE_SHIFT - ilog2(sizeof(int))) to make sure an array of * atomic_t variables with BARRIER_BUCKETS_NR elements just exactly * occupies a single memory page. */#define BARRIER_BUCKETS_NR_BITS		(PAGE_SHIFT - ilog2(sizeof(atomic_t)))#define BARRIER_BUCKETS_NR		(1<<BARRIER_BUCKETS_NR_BITS) /* Note: raid1_info.rdev can be set to NULL asynchronously by raid1_remove_disk. * There are three safe ways to access raid1_info.rdev. * 1/ when holding mddev->reconfig_mutex * 2/ when resync/recovery is known to be happening - i.e. in code that is *    called as part of performing resync/recovery. * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer *    and if it is non-NULL, increment rdev->nr_pending before dropping the *    RCU lock. * When .rdev is set to NULL, the nr_pending count checked again and if it has * been incremented, the pointer is put back in .rdev. */ struct raid1_info {	struct md_rdev	*rdev;	sector_t	head_position; 	/* When choose the best device for a read (read_balance())	 * we try to keep sequential reads one the same device	 */	sector_t	next_seq_sect;	sector_t	seq_start;}; struct r1conf {	struct mddev		*mddev;	struct raid1_info	*mirrors;	/* twice 'raid_disks' to						 * allow for replacements.						 */	int			raid_disks;	int			nonrot_disks; 	spinlock_t		device_lock; 	/* list of 'struct r1bio' that need to be processed by raid1d,	 * whether to retry a read, writeout a resync or recovery	 * block, or anything else.	 */	struct list_head	retry_list;	/* A separate list of r1bio which just need raid_end_bio_io called.	 * This mustn't happen for writes which had any errors if the superblock	 * needs to be written.	 */	struct list_head	bio_end_io_list; 	/* queue pending writes to be submitted on unplug */	struct bio_list		pending_bio_list; 	/* for use when syncing mirrors:	 * We don't allow both normal IO and resync/recovery IO at	 * the same time - resync/recovery can only happen when there	 * is no other IO.  So when either is active, the other has to wait.	 * See more details description in raid1.c near raise_barrier().	 */	wait_queue_head_t	wait_barrier;	spinlock_t		resync_lock;	atomic_t		nr_sync_pending;	atomic_t		*nr_pending;	atomic_t		*nr_waiting;	atomic_t		*nr_queued;	atomic_t		*barrier;	int			array_frozen; 	/* Set to 1 if a full sync is needed, (fresh device added).	 * Cleared when a sync completes.	 */	int			fullsync; 	mempool_t		*r1bio_pool;	mempool_t		r1buf_pool; 	struct bio_set		bio_split; 	/* temporary buffer to synchronous IO when attempting to repair	 * a read error.	 */	struct page		*tmppage; 	/* When taking over an array from a different personality, we store	 * the new thread here until we fully activate the array.	 */	struct md_thread __rcu	*thread; 	/* Keep track of cluster resync window to send to other	 * nodes.	 */	sector_t		cluster_sync_low;	sector_t		cluster_sync_high; }; /* * this is our 'private' RAID1 bio. * * it contains information about what kind of IO operations were started * for this RAID1 operation, and about their status: */ struct r1bio {	atomic_t		remaining; /* 'have we finished' count,					    * used from IRQ handlers					    */	atomic_t		behind_remaining; /* number of write-behind ios remaining						 * in this BehindIO request						 */	sector_t		sector;	int			sectors;	unsigned long		state;	struct mddev		*mddev;	/*	 * original bio going to /dev/mdx	 */	struct bio		*master_bio;	/*	 * if the IO is in READ direction, then this is where we read	 */	int			read_disk; 	struct list_head	retry_list; 	/*	 * When R1BIO_BehindIO is set, we store pages for write behind	 * in behind_master_bio.	 */	struct bio		*behind_master_bio; 	/*	 * if the IO is in WRITE direction, then multiple bios are used.	 * We choose the number when they are allocated.	 */	struct bio		*bios[];	/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/}; /* bits for r1bio.state */enum r1bio_state {	R1BIO_Uptodate,	R1BIO_IsSync,	R1BIO_BehindIO,/* Set ReadError on bios that experience a readerror so that * raid1d knows what to do with them. */	R1BIO_ReadError,/* For write-behind requests, we call bi_end_io when * the last non-write-behind device completes, providing * any write was successful.  Otherwise we call when * any write-behind write succeeds, otherwise we call * with failure when last write completes (and all failed). * * And for bio_split errors, record that bi_end_io was called * with this flag... */	R1BIO_Returned,/* If a write for this request means we can clear some * known-bad-block records, we set this flag */	R1BIO_MadeGood,	R1BIO_WriteError,	R1BIO_FailFast,}; static inline int sector_to_idx(sector_t sector){	return hash_long(sector >> BARRIER_UNIT_SECTOR_BITS,			 BARRIER_BUCKETS_NR_BITS);}#endif