Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Christoph Hellwig | 781 | 42.40% | 18 | 35.29% |
Tejun Heo | 748 | 40.61% | 13 | 25.49% |
Jens Axboe | 225 | 12.21% | 5 | 9.80% |
John Ogness | 44 | 2.39% | 2 | 3.92% |
Xiaotian Feng | 11 | 0.60% | 1 | 1.96% |
Paul Bolle | 9 | 0.49% | 2 | 3.92% |
Jan Kara | 7 | 0.38% | 2 | 3.92% |
Sahitya Tummala | 6 | 0.33% | 1 | 1.96% |
Viresh Kumar | 3 | 0.16% | 1 | 1.96% |
Ingo Molnar | 3 | 0.16% | 1 | 1.96% |
Paul E. McKenney | 1 | 0.05% | 1 | 1.96% |
Greg Kroah-Hartman | 1 | 0.05% | 1 | 1.96% |
Nikanth Karthikesan | 1 | 0.05% | 1 | 1.96% |
Jiri Slaby | 1 | 0.05% | 1 | 1.96% |
Adrian Bunk | 1 | 0.05% | 1 | 1.96% |
Total | 1842 | 51 |
// SPDX-License-Identifier: GPL-2.0 /* * Functions related to io context handling */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/bio.h> #include <linux/blkdev.h> #include <linux/slab.h> #include <linux/security.h> #include <linux/sched/task.h> #include "blk.h" #include "blk-mq-sched.h" /* * For io context allocations */ static struct kmem_cache *iocontext_cachep; #ifdef CONFIG_BLK_ICQ /** * get_io_context - increment reference count to io_context * @ioc: io_context to get * * Increment reference count to @ioc. */ static void get_io_context(struct io_context *ioc) { BUG_ON(atomic_long_read(&ioc->refcount) <= 0); atomic_long_inc(&ioc->refcount); } static void icq_free_icq_rcu(struct rcu_head *head) { struct io_cq *icq = container_of(head, struct io_cq, __rcu_head); kmem_cache_free(icq->__rcu_icq_cache, icq); } /* * Exit an icq. Called with ioc locked for blk-mq, and with both ioc * and queue locked for legacy. */ static void ioc_exit_icq(struct io_cq *icq) { struct elevator_type *et = icq->q->elevator->type; if (icq->flags & ICQ_EXITED) return; if (et->ops.exit_icq) et->ops.exit_icq(icq); icq->flags |= ICQ_EXITED; } static void ioc_exit_icqs(struct io_context *ioc) { struct io_cq *icq; spin_lock_irq(&ioc->lock); hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) ioc_exit_icq(icq); spin_unlock_irq(&ioc->lock); } /* * Release an icq. Called with ioc locked for blk-mq, and with both ioc * and queue locked for legacy. */ static void ioc_destroy_icq(struct io_cq *icq) { struct io_context *ioc = icq->ioc; struct request_queue *q = icq->q; struct elevator_type *et = q->elevator->type; lockdep_assert_held(&ioc->lock); radix_tree_delete(&ioc->icq_tree, icq->q->id); hlist_del_init(&icq->ioc_node); list_del_init(&icq->q_node); /* * Both setting lookup hint to and clearing it from @icq are done * under queue_lock. If it's not pointing to @icq now, it never * will. Hint assignment itself can race safely. */ if (rcu_access_pointer(ioc->icq_hint) == icq) rcu_assign_pointer(ioc->icq_hint, NULL); ioc_exit_icq(icq); /* * @icq->q might have gone away by the time RCU callback runs * making it impossible to determine icq_cache. Record it in @icq. */ icq->__rcu_icq_cache = et->icq_cache; icq->flags |= ICQ_DESTROYED; call_rcu(&icq->__rcu_head, icq_free_icq_rcu); } /* * Slow path for ioc release in put_io_context(). Performs double-lock * dancing to unlink all icq's and then frees ioc. */ static void ioc_release_fn(struct work_struct *work) { struct io_context *ioc = container_of(work, struct io_context, release_work); spin_lock_irq(&ioc->lock); while (!hlist_empty(&ioc->icq_list)) { struct io_cq *icq = hlist_entry(ioc->icq_list.first, struct io_cq, ioc_node); struct request_queue *q = icq->q; if (spin_trylock(&q->queue_lock)) { ioc_destroy_icq(icq); spin_unlock(&q->queue_lock); } else { /* Make sure q and icq cannot be freed. */ rcu_read_lock(); /* Re-acquire the locks in the correct order. */ spin_unlock(&ioc->lock); spin_lock(&q->queue_lock); spin_lock(&ioc->lock); /* * The icq may have been destroyed when the ioc lock * was released. */ if (!(icq->flags & ICQ_DESTROYED)) ioc_destroy_icq(icq); spin_unlock(&q->queue_lock); rcu_read_unlock(); } } spin_unlock_irq(&ioc->lock); kmem_cache_free(iocontext_cachep, ioc); } /* * Releasing icqs requires reverse order double locking and we may already be * holding a queue_lock. Do it asynchronously from a workqueue. */ static bool ioc_delay_free(struct io_context *ioc) { unsigned long flags; spin_lock_irqsave(&ioc->lock, flags); if (!hlist_empty(&ioc->icq_list)) { queue_work(system_power_efficient_wq, &ioc->release_work); spin_unlock_irqrestore(&ioc->lock, flags); return true; } spin_unlock_irqrestore(&ioc->lock, flags); return false; } /** * ioc_clear_queue - break any ioc association with the specified queue * @q: request_queue being cleared * * Walk @q->icq_list and exit all io_cq's. */ void ioc_clear_queue(struct request_queue *q) { LIST_HEAD(icq_list); spin_lock_irq(&q->queue_lock); list_splice_init(&q->icq_list, &icq_list); spin_unlock_irq(&q->queue_lock); rcu_read_lock(); while (!list_empty(&icq_list)) { struct io_cq *icq = list_entry(icq_list.next, struct io_cq, q_node); spin_lock_irq(&icq->ioc->lock); if (!(icq->flags & ICQ_DESTROYED)) ioc_destroy_icq(icq); spin_unlock_irq(&icq->ioc->lock); } rcu_read_unlock(); } #else /* CONFIG_BLK_ICQ */ static inline void ioc_exit_icqs(struct io_context *ioc) { } static inline bool ioc_delay_free(struct io_context *ioc) { return false; } #endif /* CONFIG_BLK_ICQ */ /** * put_io_context - put a reference of io_context * @ioc: io_context to put * * Decrement reference count of @ioc and release it if the count reaches * zero. */ void put_io_context(struct io_context *ioc) { BUG_ON(atomic_long_read(&ioc->refcount) <= 0); if (atomic_long_dec_and_test(&ioc->refcount) && !ioc_delay_free(ioc)) kmem_cache_free(iocontext_cachep, ioc); } EXPORT_SYMBOL_GPL(put_io_context); /* Called by the exiting task */ void exit_io_context(struct task_struct *task) { struct io_context *ioc; task_lock(task); ioc = task->io_context; task->io_context = NULL; task_unlock(task); if (atomic_dec_and_test(&ioc->active_ref)) { ioc_exit_icqs(ioc); put_io_context(ioc); } } static struct io_context *alloc_io_context(gfp_t gfp_flags, int node) { struct io_context *ioc; ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO, node); if (unlikely(!ioc)) return NULL; atomic_long_set(&ioc->refcount, 1); atomic_set(&ioc->active_ref, 1); #ifdef CONFIG_BLK_ICQ spin_lock_init(&ioc->lock); INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC); INIT_HLIST_HEAD(&ioc->icq_list); INIT_WORK(&ioc->release_work, ioc_release_fn); #endif ioc->ioprio = IOPRIO_DEFAULT; return ioc; } int set_task_ioprio(struct task_struct *task, int ioprio) { int err; const struct cred *cred = current_cred(), *tcred; rcu_read_lock(); tcred = __task_cred(task); if (!uid_eq(tcred->uid, cred->euid) && !uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) { rcu_read_unlock(); return -EPERM; } rcu_read_unlock(); err = security_task_setioprio(task, ioprio); if (err) return err; task_lock(task); if (unlikely(!task->io_context)) { struct io_context *ioc; task_unlock(task); ioc = alloc_io_context(GFP_ATOMIC, NUMA_NO_NODE); if (!ioc) return -ENOMEM; task_lock(task); if (task->flags & PF_EXITING) { kmem_cache_free(iocontext_cachep, ioc); goto out; } if (task->io_context) kmem_cache_free(iocontext_cachep, ioc); else task->io_context = ioc; } task->io_context->ioprio = ioprio; out: task_unlock(task); return 0; } EXPORT_SYMBOL_GPL(set_task_ioprio); int __copy_io(unsigned long clone_flags, struct task_struct *tsk) { struct io_context *ioc = current->io_context; /* * Share io context with parent, if CLONE_IO is set */ if (clone_flags & CLONE_IO) { atomic_inc(&ioc->active_ref); tsk->io_context = ioc; } else if (ioprio_valid(ioc->ioprio)) { tsk->io_context = alloc_io_context(GFP_KERNEL, NUMA_NO_NODE); if (!tsk->io_context) return -ENOMEM; tsk->io_context->ioprio = ioc->ioprio; } return 0; } #ifdef CONFIG_BLK_ICQ /** * ioc_lookup_icq - lookup io_cq from ioc * @q: the associated request_queue * * Look up io_cq associated with @ioc - @q pair from @ioc. Must be called * with @q->queue_lock held. */ struct io_cq *ioc_lookup_icq(struct request_queue *q) { struct io_context *ioc = current->io_context; struct io_cq *icq; lockdep_assert_held(&q->queue_lock); /* * icq's are indexed from @ioc using radix tree and hint pointer, * both of which are protected with RCU. All removals are done * holding both q and ioc locks, and we're holding q lock - if we * find a icq which points to us, it's guaranteed to be valid. */ rcu_read_lock(); icq = rcu_dereference(ioc->icq_hint); if (icq && icq->q == q) goto out; icq = radix_tree_lookup(&ioc->icq_tree, q->id); if (icq && icq->q == q) rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */ else icq = NULL; out: rcu_read_unlock(); return icq; } EXPORT_SYMBOL(ioc_lookup_icq); /** * ioc_create_icq - create and link io_cq * @q: request_queue of interest * * Make sure io_cq linking @ioc and @q exists. If icq doesn't exist, they * will be created using @gfp_mask. * * The caller is responsible for ensuring @ioc won't go away and @q is * alive and will stay alive until this function returns. */ static struct io_cq *ioc_create_icq(struct request_queue *q) { struct io_context *ioc = current->io_context; struct elevator_type *et = q->elevator->type; struct io_cq *icq; /* allocate stuff */ icq = kmem_cache_alloc_node(et->icq_cache, GFP_ATOMIC | __GFP_ZERO, q->node); if (!icq) return NULL; if (radix_tree_maybe_preload(GFP_ATOMIC) < 0) { kmem_cache_free(et->icq_cache, icq); return NULL; } icq->ioc = ioc; icq->q = q; INIT_LIST_HEAD(&icq->q_node); INIT_HLIST_NODE(&icq->ioc_node); /* lock both q and ioc and try to link @icq */ spin_lock_irq(&q->queue_lock); spin_lock(&ioc->lock); if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) { hlist_add_head(&icq->ioc_node, &ioc->icq_list); list_add(&icq->q_node, &q->icq_list); if (et->ops.init_icq) et->ops.init_icq(icq); } else { kmem_cache_free(et->icq_cache, icq); icq = ioc_lookup_icq(q); if (!icq) printk(KERN_ERR "cfq: icq link failed!\n"); } spin_unlock(&ioc->lock); spin_unlock_irq(&q->queue_lock); radix_tree_preload_end(); return icq; } struct io_cq *ioc_find_get_icq(struct request_queue *q) { struct io_context *ioc = current->io_context; struct io_cq *icq = NULL; if (unlikely(!ioc)) { ioc = alloc_io_context(GFP_ATOMIC, q->node); if (!ioc) return NULL; task_lock(current); if (current->io_context) { kmem_cache_free(iocontext_cachep, ioc); ioc = current->io_context; } else { current->io_context = ioc; } get_io_context(ioc); task_unlock(current); } else { get_io_context(ioc); spin_lock_irq(&q->queue_lock); icq = ioc_lookup_icq(q); spin_unlock_irq(&q->queue_lock); } if (!icq) { icq = ioc_create_icq(q); if (!icq) { put_io_context(ioc); return NULL; } } return icq; } EXPORT_SYMBOL_GPL(ioc_find_get_icq); #endif /* CONFIG_BLK_ICQ */ static int __init blk_ioc_init(void) { iocontext_cachep = kmem_cache_create("blkdev_ioc", sizeof(struct io_context), 0, SLAB_PANIC, NULL); return 0; } subsys_initcall(blk_ioc_init);
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