^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Functions related to io context handling
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/bio.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <linux/blkdev.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/sched/task.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include "blk.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) * For io context allocations
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) static struct kmem_cache *iocontext_cachep;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * get_io_context - increment reference count to io_context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * @ioc: io_context to get
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Increment reference count to @ioc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) void get_io_context(struct io_context *ioc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) atomic_long_inc(&ioc->refcount);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) static void icq_free_icq_rcu(struct rcu_head *head)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) struct io_cq *icq = container_of(head, struct io_cq, __rcu_head);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) kmem_cache_free(icq->__rcu_icq_cache, icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * Exit an icq. Called with ioc locked for blk-mq, and with both ioc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * and queue locked for legacy.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) static void ioc_exit_icq(struct io_cq *icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) struct elevator_type *et = icq->q->elevator->type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) if (icq->flags & ICQ_EXITED)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) if (et->ops.exit_icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) et->ops.exit_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) icq->flags |= ICQ_EXITED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * Release an icq. Called with ioc locked for blk-mq, and with both ioc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * and queue locked for legacy.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) static void ioc_destroy_icq(struct io_cq *icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) struct io_context *ioc = icq->ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) struct request_queue *q = icq->q;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) struct elevator_type *et = q->elevator->type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) lockdep_assert_held(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) radix_tree_delete(&ioc->icq_tree, icq->q->id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) hlist_del_init(&icq->ioc_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) list_del_init(&icq->q_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) * Both setting lookup hint to and clearing it from @icq are done
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) * under queue_lock. If it's not pointing to @icq now, it never
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) * will. Hint assignment itself can race safely.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) if (rcu_access_pointer(ioc->icq_hint) == icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) rcu_assign_pointer(ioc->icq_hint, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) ioc_exit_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) * @icq->q might have gone away by the time RCU callback runs
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) * making it impossible to determine icq_cache. Record it in @icq.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) icq->__rcu_icq_cache = et->icq_cache;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) icq->flags |= ICQ_DESTROYED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) call_rcu(&icq->__rcu_head, icq_free_icq_rcu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) * Slow path for ioc release in put_io_context(). Performs double-lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * dancing to unlink all icq's and then frees ioc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) static void ioc_release_fn(struct work_struct *work)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) struct io_context *ioc = container_of(work, struct io_context,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) release_work);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) spin_lock_irq(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) while (!hlist_empty(&ioc->icq_list)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) struct io_cq *icq = hlist_entry(ioc->icq_list.first,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) struct io_cq, ioc_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) struct request_queue *q = icq->q;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) if (spin_trylock(&q->queue_lock)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) ioc_destroy_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) spin_unlock(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) /* Make sure q and icq cannot be freed. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) /* Re-acquire the locks in the correct order. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) spin_unlock(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) spin_lock(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) spin_lock(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) * The icq may have been destroyed when the ioc lock
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) * was released.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) if (!(icq->flags & ICQ_DESTROYED))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) ioc_destroy_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) spin_unlock(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) spin_unlock_irq(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) kmem_cache_free(iocontext_cachep, ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) * put_io_context - put a reference of io_context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) * @ioc: io_context to put
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) * Decrement reference count of @ioc and release it if the count reaches
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) * zero.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) void put_io_context(struct io_context *ioc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) bool free_ioc = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) if (ioc == NULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) * Releasing ioc requires reverse order double locking and we may
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) * already be holding a queue_lock. Do it asynchronously from wq.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) if (atomic_long_dec_and_test(&ioc->refcount)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) spin_lock_irqsave(&ioc->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) if (!hlist_empty(&ioc->icq_list))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) queue_work(system_power_efficient_wq,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) &ioc->release_work);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) free_ioc = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) spin_unlock_irqrestore(&ioc->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) if (free_ioc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) kmem_cache_free(iocontext_cachep, ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) * put_io_context_active - put active reference on ioc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) * @ioc: ioc of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) * Undo get_io_context_active(). If active reference reaches zero after
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) * put, @ioc can never issue further IOs and ioscheds are notified.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) void put_io_context_active(struct io_context *ioc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) struct io_cq *icq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) if (!atomic_dec_and_test(&ioc->active_ref)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) put_io_context(ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) spin_lock_irq(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) if (icq->flags & ICQ_EXITED)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) ioc_exit_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) spin_unlock_irq(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) put_io_context(ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) /* Called by the exiting task */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) void exit_io_context(struct task_struct *task)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) struct io_context *ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) task_lock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) ioc = task->io_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) task->io_context = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) task_unlock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) atomic_dec(&ioc->nr_tasks);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) put_io_context_active(ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) static void __ioc_clear_queue(struct list_head *icq_list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) while (!list_empty(icq_list)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) struct io_cq *icq = list_entry(icq_list->next,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) struct io_cq, q_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) struct io_context *ioc = icq->ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) spin_lock_irqsave(&ioc->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) if (icq->flags & ICQ_DESTROYED) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) spin_unlock_irqrestore(&ioc->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) ioc_destroy_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) spin_unlock_irqrestore(&ioc->lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) * ioc_clear_queue - break any ioc association with the specified queue
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) * @q: request_queue being cleared
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) * Walk @q->icq_list and exit all io_cq's.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) void ioc_clear_queue(struct request_queue *q)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) LIST_HEAD(icq_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) spin_lock_irq(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) list_splice_init(&q->icq_list, &icq_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) spin_unlock_irq(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) __ioc_clear_queue(&icq_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) struct io_context *ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) if (unlikely(!ioc))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) /* initialize */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) atomic_long_set(&ioc->refcount, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) atomic_set(&ioc->nr_tasks, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) atomic_set(&ioc->active_ref, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) spin_lock_init(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) INIT_HLIST_HEAD(&ioc->icq_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) INIT_WORK(&ioc->release_work, ioc_release_fn);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) * Try to install. ioc shouldn't be installed if someone else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) * already did or @task, which isn't %current, is exiting. Note
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) * that we need to allow ioc creation on exiting %current as exit
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) * path may issue IOs from e.g. exit_files(). The exit path is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) * responsible for not issuing IO after exit_io_context().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) task_lock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) if (!task->io_context &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) (task == current || !(task->flags & PF_EXITING)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) task->io_context = ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) kmem_cache_free(iocontext_cachep, ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) ret = task->io_context ? 0 : -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) task_unlock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) * get_task_io_context - get io_context of a task
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) * @task: task of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) * @gfp_flags: allocation flags, used if allocation is necessary
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) * @node: allocation node, used if allocation is necessary
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) * Return io_context of @task. If it doesn't exist, it is created with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) * @gfp_flags and @node. The returned io_context has its reference count
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) * incremented.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) * This function always goes through task_lock() and it's better to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) * %current->io_context + get_io_context() for %current.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) struct io_context *get_task_io_context(struct task_struct *task,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) gfp_t gfp_flags, int node)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) struct io_context *ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) might_sleep_if(gfpflags_allow_blocking(gfp_flags));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) task_lock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) ioc = task->io_context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) if (likely(ioc)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) get_io_context(ioc);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) task_unlock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) return ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) task_unlock(task);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) } while (!create_task_io_context(task, gfp_flags, node));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) * ioc_lookup_icq - lookup io_cq from ioc
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) * @ioc: the associated io_context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) * @q: the associated request_queue
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) * Look up io_cq associated with @ioc - @q pair from @ioc. Must be called
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) * with @q->queue_lock held.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) struct io_cq *icq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) lockdep_assert_held(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) * icq's are indexed from @ioc using radix tree and hint pointer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) * both of which are protected with RCU. All removals are done
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) * holding both q and ioc locks, and we're holding q lock - if we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) * find a icq which points to us, it's guaranteed to be valid.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) rcu_read_lock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) icq = rcu_dereference(ioc->icq_hint);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) if (icq && icq->q == q)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) icq = radix_tree_lookup(&ioc->icq_tree, q->id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) if (icq && icq->q == q)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) icq = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) rcu_read_unlock();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) return icq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) EXPORT_SYMBOL(ioc_lookup_icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) * ioc_create_icq - create and link io_cq
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) * @ioc: io_context of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) * @q: request_queue of interest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) * @gfp_mask: allocation mask
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) * Make sure io_cq linking @ioc and @q exists. If icq doesn't exist, they
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) * will be created using @gfp_mask.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) * The caller is responsible for ensuring @ioc won't go away and @q is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) * alive and will stay alive until this function returns.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) gfp_t gfp_mask)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) struct elevator_type *et = q->elevator->type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) struct io_cq *icq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) /* allocate stuff */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) q->node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381) if (!icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) if (radix_tree_maybe_preload(gfp_mask) < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) kmem_cache_free(et->icq_cache, icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) icq->ioc = ioc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) icq->q = q;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) INIT_LIST_HEAD(&icq->q_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) INIT_HLIST_NODE(&icq->ioc_node);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) /* lock both q and ioc and try to link @icq */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) spin_lock_irq(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396) spin_lock(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) hlist_add_head(&icq->ioc_node, &ioc->icq_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) list_add(&icq->q_node, &q->icq_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) if (et->ops.init_icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) et->ops.init_icq(icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) kmem_cache_free(et->icq_cache, icq);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) icq = ioc_lookup_icq(ioc, q);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) if (!icq)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) printk(KERN_ERR "cfq: icq link failed!\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) spin_unlock(&ioc->lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) spin_unlock_irq(&q->queue_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) radix_tree_preload_end();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) return icq;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) static int __init blk_ioc_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) iocontext_cachep = kmem_cache_create("blkdev_ioc",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) sizeof(struct io_context), 0, SLAB_PANIC, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) subsys_initcall(blk_ioc_init);
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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