From 518257b13276d07a19e6ae0608b8e5ee73383ce4 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 17 Mar 2016 16:32:10 -0400 Subject: [PATCH] dm mpath: switch to using bitops for state flags Mechanical change that doesn't make any real effort to reduce the use of m->lock; that will come later (once atomics are used for counters, etc). Suggested-by: Hannes Reinecke Reviewed-by: Hannes Reinecke Tested-by: Hannes Reinecke Signed-off-by: Mike Snitzer --- drivers/md/dm-mpath.c | 131 ++++++++++++++++++++++++------------------ 1 file changed, 75 insertions(+), 56 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 677ba223e2ae..598d4a1123e0 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -83,13 +83,7 @@ struct multipath { struct priority_group *current_pg; struct priority_group *next_pg; /* Switch to this PG if set */ - bool queue_io:1; /* Must we queue all I/O? */ - bool queue_if_no_path:1; /* Queue I/O if last path fails? */ - bool saved_queue_if_no_path:1; /* Saved state during suspension */ - bool retain_attached_hw_handler:1; /* If there's already a hw_handler present, don't change it. */ - bool pg_init_disabled:1; /* pg_init is not currently allowed */ - bool pg_init_required:1; /* pg_init needs calling? */ - bool pg_init_delay_retry:1; /* Delay pg_init retry? */ + unsigned long flags; /* Multipath state flags */ unsigned pg_init_retries; /* Number of times to retry pg_init */ unsigned pg_init_count; /* Number of times pg_init called */ @@ -122,6 +116,17 @@ static struct workqueue_struct *kmultipathd, *kmpath_handlerd; static void trigger_event(struct work_struct *work); static void activate_path(struct work_struct *work); +/*----------------------------------------------- + * Multipath state flags. + *-----------------------------------------------*/ + +#define MPATHF_QUEUE_IO 0 /* Must we queue all I/O? */ +#define MPATHF_QUEUE_IF_NO_PATH 1 /* Queue I/O if last path fails? */ +#define MPATHF_SAVED_QUEUE_IF_NO_PATH 2 /* Saved state during suspension */ +#define MPATHF_RETAIN_ATTACHED_HW_HANDLER 3 /* If there's already a hw_handler present, don't change it. */ +#define MPATHF_PG_INIT_DISABLED 4 /* pg_init is not currently allowed */ +#define MPATHF_PG_INIT_REQUIRED 5 /* pg_init needs calling? */ +#define MPATHF_PG_INIT_DELAY_RETRY 6 /* Delay pg_init retry? */ /*----------------------------------------------- * Allocation routines @@ -189,7 +194,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti, bool use_blk_mq) if (m) { INIT_LIST_HEAD(&m->priority_groups); spin_lock_init(&m->lock); - m->queue_io = true; + set_bit(MPATHF_QUEUE_IO, &m->flags); m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT; INIT_WORK(&m->trigger_event, trigger_event); init_waitqueue_head(&m->pg_init_wait); @@ -274,17 +279,17 @@ static int __pg_init_all_paths(struct multipath *m) struct pgpath *pgpath; unsigned long pg_init_delay = 0; - if (m->pg_init_in_progress || m->pg_init_disabled) + if (m->pg_init_in_progress || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) return 0; m->pg_init_count++; - m->pg_init_required = false; + clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); /* Check here to reset pg_init_required */ if (!m->current_pg) return 0; - if (m->pg_init_delay_retry) + if (test_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags)) pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ? m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS); list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) { @@ -304,11 +309,11 @@ static void __switch_pg(struct multipath *m, struct pgpath *pgpath) /* Must we initialise the PG first, and queue I/O till it's ready? */ if (m->hw_handler_name) { - m->pg_init_required = true; - m->queue_io = true; + set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); + set_bit(MPATHF_QUEUE_IO, &m->flags); } else { - m->pg_init_required = false; - m->queue_io = false; + clear_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); + clear_bit(MPATHF_QUEUE_IO, &m->flags); } m->pg_init_count = 0; @@ -337,7 +342,7 @@ static void __choose_pgpath(struct multipath *m, size_t nr_bytes) bool bypassed = true; if (!m->nr_valid_paths) { - m->queue_io = false; + clear_bit(MPATHF_QUEUE_IO, &m->flags); goto failed; } @@ -365,7 +370,7 @@ static void __choose_pgpath(struct multipath *m, size_t nr_bytes) continue; if (!__choose_path_in_pg(m, pg, nr_bytes)) { if (!bypassed) - m->pg_init_delay_retry = true; + set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); return; } } @@ -389,8 +394,9 @@ failed: */ static int __must_push_back(struct multipath *m) { - return (m->queue_if_no_path || - (m->queue_if_no_path != m->saved_queue_if_no_path && + return (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) || + ((test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) != + test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) && dm_noflush_suspending(m->ti))); } @@ -411,7 +417,7 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, spin_lock_irq(&m->lock); /* Do we need to select a new pgpath? */ - if (!m->current_pgpath || !m->queue_io) + if (!m->current_pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags)) __choose_pgpath(m, nr_bytes); pgpath = m->current_pgpath; @@ -420,7 +426,8 @@ static int __multipath_map(struct dm_target *ti, struct request *clone, if (!__must_push_back(m)) r = -EIO; /* Failed */ goto out_unlock; - } else if (m->queue_io || m->pg_init_required) { + } else if (test_bit(MPATHF_QUEUE_IO, &m->flags) || + test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { __pg_init_all_paths(m); goto out_unlock; } @@ -503,11 +510,22 @@ static int queue_if_no_path(struct multipath *m, bool queue_if_no_path, spin_lock_irqsave(&m->lock, flags); - if (save_old_value) - m->saved_queue_if_no_path = m->queue_if_no_path; + if (save_old_value) { + if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) + set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); + else + clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); + } else { + if (queue_if_no_path) + set_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); + else + clear_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags); + } + if (queue_if_no_path) + set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); else - m->saved_queue_if_no_path = queue_if_no_path; - m->queue_if_no_path = queue_if_no_path; + clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); + spin_unlock_irqrestore(&m->lock, flags); if (!queue_if_no_path) @@ -600,10 +618,10 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps goto bad; } - if (m->retain_attached_hw_handler || m->hw_handler_name) + if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags) || m->hw_handler_name) q = bdev_get_queue(p->path.dev->bdev); - if (m->retain_attached_hw_handler) { + if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) { retain: attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL); if (attached_handler_name) { @@ -808,7 +826,7 @@ static int parse_features(struct dm_arg_set *as, struct multipath *m) } if (!strcasecmp(arg_name, "retain_attached_hw_handler")) { - m->retain_attached_hw_handler = true; + set_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags); continue; } @@ -944,20 +962,16 @@ static void multipath_wait_for_pg_init_completion(struct multipath *m) static void flush_multipath_work(struct multipath *m) { - unsigned long flags; - - spin_lock_irqsave(&m->lock, flags); - m->pg_init_disabled = true; - spin_unlock_irqrestore(&m->lock, flags); + set_bit(MPATHF_PG_INIT_DISABLED, &m->flags); + smp_mb__after_atomic(); flush_workqueue(kmpath_handlerd); multipath_wait_for_pg_init_completion(m); flush_workqueue(kmultipathd); flush_work(&m->trigger_event); - spin_lock_irqsave(&m->lock, flags); - m->pg_init_disabled = false; - spin_unlock_irqrestore(&m->lock, flags); + clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags); + smp_mb__after_atomic(); } static void multipath_dtr(struct dm_target *ti) @@ -1152,8 +1166,8 @@ static bool pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath) spin_lock_irqsave(&m->lock, flags); - if (m->pg_init_count <= m->pg_init_retries && !m->pg_init_disabled) - m->pg_init_required = true; + if (m->pg_init_count <= m->pg_init_retries && !test_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) + set_bit(MPATHF_PG_INIT_REQUIRED, &m->flags); else limit_reached = true; @@ -1219,19 +1233,23 @@ static void pg_init_done(void *data, int errors) m->current_pgpath = NULL; m->current_pg = NULL; } - } else if (!m->pg_init_required) + } else if (!test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) pg->bypassed = false; if (--m->pg_init_in_progress) /* Activations of other paths are still on going */ goto out; - if (m->pg_init_required) { - m->pg_init_delay_retry = delay_retry; + if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) { + if (delay_retry) + set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); + else + clear_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags); + if (__pg_init_all_paths(m)) goto out; } - m->queue_io = false; + clear_bit(MPATHF_QUEUE_IO, &m->flags); /* * Wake up any thread waiting to suspend. @@ -1300,7 +1318,7 @@ static int do_end_io(struct multipath *m, struct request *clone, spin_lock_irqsave(&m->lock, flags); if (!m->nr_valid_paths) { - if (!m->queue_if_no_path) { + if (!test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) { if (!__must_push_back(m)) r = -EIO; } else { @@ -1364,11 +1382,12 @@ static void multipath_postsuspend(struct dm_target *ti) static void multipath_resume(struct dm_target *ti) { struct multipath *m = ti->private; - unsigned long flags; - spin_lock_irqsave(&m->lock, flags); - m->queue_if_no_path = m->saved_queue_if_no_path; - spin_unlock_irqrestore(&m->lock, flags); + if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) + set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); + else + clear_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags); + smp_mb__after_atomic(); } /* @@ -1402,19 +1421,19 @@ static void multipath_status(struct dm_target *ti, status_type_t type, /* Features */ if (type == STATUSTYPE_INFO) - DMEMIT("2 %u %u ", m->queue_io, m->pg_init_count); + DMEMIT("2 %u %u ", test_bit(MPATHF_QUEUE_IO, &m->flags), m->pg_init_count); else { - DMEMIT("%u ", m->queue_if_no_path + + DMEMIT("%u ", test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags) + (m->pg_init_retries > 0) * 2 + (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 + - m->retain_attached_hw_handler); - if (m->queue_if_no_path) + test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)); + if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) DMEMIT("queue_if_no_path "); if (m->pg_init_retries) DMEMIT("pg_init_retries %u ", m->pg_init_retries); if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs); - if (m->retain_attached_hw_handler) + if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) DMEMIT("retain_attached_hw_handler "); } @@ -1572,7 +1591,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, __choose_pgpath(m, 0); if (m->current_pgpath) { - if (!m->queue_io) { + if (!test_bit(MPATHF_QUEUE_IO, &m->flags)) { *bdev = m->current_pgpath->path.dev->bdev; *mode = m->current_pgpath->path.dev->mode; r = 0; @@ -1582,7 +1601,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, } } else { /* No path is available */ - if (m->queue_if_no_path) + if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) r = -ENOTCONN; else r = -EIO; @@ -1596,7 +1615,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, /* Path status changed, redo selection */ __choose_pgpath(m, 0); } - if (m->pg_init_required) + if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags)) __pg_init_all_paths(m); spin_unlock_irqrestore(&m->lock, flags); dm_table_run_md_queue_async(m->ti->table); @@ -1657,7 +1676,7 @@ static int multipath_busy(struct dm_target *ti) /* pg_init in progress or no paths available */ if (m->pg_init_in_progress || - (!m->nr_valid_paths && m->queue_if_no_path)) { + (!m->nr_valid_paths && test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))) { busy = true; goto out; } -- 2.20.1