litmus-rt.git - The LITMUS^RT kernel.

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author	Linus Torvalds <torvalds@g5.osdl.org>	2006-03-25 11:41:09 -0500
committer	Linus Torvalds <torvalds@g5.osdl.org>	2006-03-25 11:41:09 -0500
commit	1e8c573933fd7975679766850252ad08667e5ca4 (patch)
tree	9600d0c7ee5ea8925f3c4dc30680c819e0363805 /lib
parent	d71eecf3b8e893757cc3dec560c96a32ac090890 (diff)
parent	232443e2c90cc2930624dec89df327615b002c55 (diff)

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial

* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (21 commits) BUG_ON() Conversion in drivers/video/ BUG_ON() Conversion in drivers/parisc/ BUG_ON() Conversion in drivers/block/ BUG_ON() Conversion in sound/sparc/cs4231.c BUG_ON() Conversion in drivers/s390/block/dasd.c BUG_ON() Conversion in lib/swiotlb.c BUG_ON() Conversion in kernel/cpu.c BUG_ON() Conversion in ipc/msg.c BUG_ON() Conversion in block/elevator.c BUG_ON() Conversion in fs/coda/ BUG_ON() Conversion in fs/binfmt_elf_fdpic.c BUG_ON() Conversion in input/serio/hil_mlc.c BUG_ON() Conversion in md/dm-hw-handler.c BUG_ON() Conversion in md/bitmap.c The comment describing how MS_ASYNC works in msync.c is confusing rcu: undeclared variable used in documentation fix typos "wich" -> "which" typo patch for fs/ufs/super.c Fix simple typos tabify drivers/char/Makefile ...

Diffstat (limited to 'lib')

-rw-r--r--

lib/swiotlb.c

1 files changed, 12 insertions, 20 deletions

         else
                 stride = 1;
-        if (!nslots)
+        BUG_ON(!nslots);
-                BUG();
         /*
          * Find suitable number of IO TLB entries size that will fit this
         case SYNC_FOR_CPU:
                 if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
                         memcpy(buffer, dma_addr, size);
-                else if (dir != DMA_TO_DEVICE)
+                else
-                        BUG();
+                        BUG_ON(dir != DMA_TO_DEVICE);
                 break;
         case SYNC_FOR_DEVICE:
                 if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
                         memcpy(dma_addr, buffer, size);
-                else if (dir != DMA_FROM_DEVICE)
+                else
-                        BUG();
+                        BUG_ON(dir != DMA_FROM_DEVICE);
                 break;
         default:
                 BUG();
         unsigned long dev_addr = virt_to_phys(ptr);
         void *map;
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         /*
          * If the pointer passed in happens to be in the device's DMA window,
          * we can safely return the device addr and not worry about bounce
 {
         char *dma_addr = phys_to_virt(dev_addr);
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
                 unmap_single(hwdev, dma_addr, size, dir);
         else if (dir == DMA_FROM_DEVICE)
 {
         char *dma_addr = phys_to_virt(dev_addr);
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
                 sync_single(hwdev, dma_addr, size, dir, target);
         else if (dir == DMA_FROM_DEVICE)
 {
         char *dma_addr = phys_to_virt(dev_addr) + offset;
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
                 sync_single(hwdev, dma_addr, size, dir, target);
         else if (dir == DMA_FROM_DEVICE)
         unsigned long dev_addr;
         int i;
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         for (i = 0; i < nelems; i++, sg++) {
                 addr = SG_ENT_VIRT_ADDRESS(sg);
 {
         int i;
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         for (i = 0; i < nelems; i++, sg++)
                 if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
 {
         int i;
-        if (dir == DMA_NONE)
+        BUG_ON(dir == DMA_NONE);
-                BUG();
         for (i = 0; i < nelems; i++, sg++)
                 if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))

/* * Block device elevator/IO-scheduler. * * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE * * 30042000 Jens Axboe <axboe@kernel.dk> : * * Split the elevator a bit so that it is possible to choose a different * one or even write a new "plug in". There are three pieces: * - elevator_fn, inserts a new request in the queue list * - elevator_merge_fn, decides whether a new buffer can be merged with * an existing request * - elevator_dequeue_fn, called when a request is taken off the active list * * 20082000 Dave Jones <davej@suse.de> : * Removed tests for max-bomb-segments, which was breaking elvtune * when run without -bN * * Jens: * - Rework again to work with bio instead of buffer_heads * - loose bi_dev comparisons, partition handling is right now * - completely modularize elevator setup and teardown * */ #include <linux/kernel.h> #include <linux/fs.h> #include <linux/blkdev.h> #include <linux/elevator.h> #include <linux/bio.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/compiler.h> #include <linux/delay.h> #include <linux/blktrace_api.h> #include <linux/hash.h> #include <asm/uaccess.h> static DEFINE_SPINLOCK(elv_list_lock); static LIST_HEAD(elv_list); /* * Merge hash stuff. */ static const int elv_hash_shift = 6; #define ELV_HASH_BLOCK(sec) ((sec) >> 3) #define ELV_HASH_FN(sec) (hash_long(ELV_HASH_BLOCK((sec)), elv_hash_shift)) #define ELV_HASH_ENTRIES (1 << elv_hash_shift) #define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) #define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash)) /* * Query io scheduler to see if the current process issuing bio may be * merged with rq. */ static int elv_iosched_allow_merge(struct request *rq, struct bio *bio) { request_queue_t *q = rq->q; elevator_t *e = q->elevator; if (e->ops->elevator_allow_merge_fn) return e->ops->elevator_allow_merge_fn(q, rq, bio); return 1; } /* * can we safely merge with this request? */ inline int elv_rq_merge_ok(struct request *rq, struct bio *bio) { if (!rq_mergeable(rq)) return 0; /* * different data direction or already started, don't merge */ if (bio_data_dir(bio) != rq_data_dir(rq)) return 0; /* * must be same device and not a special request */ if (rq->rq_disk != bio->bi_bdev->bd_disk || rq->special) return 0; if (!elv_iosched_allow_merge(rq, bio)) return 0; return 1; } EXPORT_SYMBOL(elv_rq_merge_ok); static inline int elv_try_merge(struct request *__rq, struct bio *bio) { int ret = ELEVATOR_NO_MERGE; /* * we can merge and sequence is ok, check if it's possible */ if (elv_rq_merge_ok(__rq, bio)) { if (__rq->sector + __rq->nr_sectors == bio->bi_sector) ret = ELEVATOR_BACK_MERGE; else if (__rq->sector - bio_sectors(bio) == bio->bi_sector) ret = ELEVATOR_FRONT_MERGE; } return ret; } static struct elevator_type *elevator_find(const char *name) { struct elevator_type *e; struct list_head *entry; list_for_each(entry, &elv_list) { e = list_entry(entry, struct elevator_type, list); if (!strcmp(e->elevator_name, name)) return e; } return NULL; } static void elevator_put(struct elevator_type *e) { module_put(e->elevator_owner); } static struct elevator_type *elevator_get(const char *name) { struct elevator_type *e; spin_lock(&elv_list_lock); e = elevator_find(name); if (e && !try_module_get(e->elevator_owner)) e = NULL; spin_unlock(&elv_list_lock); return e; } static void *elevator_init_queue(request_queue_t *q, struct elevator_queue *eq) { return eq->ops->elevator_init_fn(q); } static void elevator_attach(request_queue_t *q, struct elevator_queue *eq, void *data) { q->elevator = eq; eq->elevator_data = data; } static char chosen_elevator[16]; static int __init elevator_setup(char *str) { /* * Be backwards-compatible with previous kernels, so users * won't get the wrong elevator. */ if (!strcmp(str, "as")) strcpy(chosen_elevator, "anticipatory"); else strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1); return 1; } __setup("elevator=", elevator_setup); static struct kobj_type elv_ktype; static elevator_t *elevator_alloc(request_queue_t *q, struct elevator_type *e) { elevator_t *eq; int i; eq = kmalloc_node(sizeof(elevator_t), GFP_KERNEL, q->node); if (unlikely(!eq)) goto err; memset(eq, 0, sizeof(*eq)); eq->ops = &e->ops; eq->elevator_type = e; kobject_init(&eq->kobj); snprintf(eq->kobj.name, KOBJ_NAME_LEN, "%s", "iosched"); eq->kobj.ktype = &elv_ktype; mutex_init(&eq->sysfs_lock); eq->hash = kmalloc_node(sizeof(struct hlist_head) * ELV_HASH_ENTRIES, GFP_KERNEL, q->node); if (!eq->hash) goto err; for (i = 0; i < ELV_HASH_ENTRIES; i++) INIT_HLIST_HEAD(&eq->hash[i]); return eq; err: kfree(eq); elevator_put(e); return NULL; } static void elevator_release(struct kobject *kobj) { elevator_t *e = container_of(kobj, elevator_t, kobj); elevator_put(e->elevator_type); kfree(e->hash); kfree(e); } int elevator_init(request_queue_t *q, char *name) { struct elevator_type *e = NULL; struct elevator_queue *eq; int ret = 0; void *data; INIT_LIST_HEAD(&q->queue_head); q->last_merge = NULL; q->end_sector = 0; q->boundary_rq = NULL; if (name && !(e = elevator_get(name))) return -EINVAL; if (!e && *chosen_elevator && !(e = elevator_get(chosen_elevator))) printk("I/O scheduler %s not found\n", chosen_elevator); if (!e && !(e = elevator_get(CONFIG_DEFAULT_IOSCHED))) { printk("Default I/O scheduler not found, using no-op\n"); e = elevator_get("noop"); } eq = elevator_alloc(q, e); if (!eq) return -ENOMEM; data = elevator_init_queue(q, eq); if (!data) { kobject_put(&eq->kobj); return -ENOMEM; } elevator_attach(q, eq, data); return ret; } EXPORT_SYMBOL(elevator_init); void elevator_exit(elevator_t *e) { mutex_lock(&e->sysfs_lock); if (e->ops->elevator_exit_fn) e->ops->elevator_exit_fn(e); e->ops = NULL; mutex_unlock(&e->sysfs_lock); kobject_put(&e->kobj); } EXPORT_SYMBOL(elevator_exit); static void elv_activate_rq(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; if (e->ops->elevator_activate_req_fn) e->ops->elevator_activate_req_fn(q, rq); } static void elv_deactivate_rq(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; if (e->ops->elevator_deactivate_req_fn) e->ops->elevator_deactivate_req_fn(q, rq); } static inline void __elv_rqhash_del(struct request *rq) { hlist_del_init(&rq->hash); } static void elv_rqhash_del(request_queue_t *q, struct request *rq) { if (ELV_ON_HASH(rq)) __elv_rqhash_del(rq); } static void elv_rqhash_add(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; BUG_ON(ELV_ON_HASH(rq)); hlist_add_head(&rq->hash, &e->hash[ELV_HASH_FN(rq_hash_key(rq))]); } static void elv_rqhash_reposition(request_queue_t *q, struct request *rq) { __elv_rqhash_del(rq); elv_rqhash_add(q, rq); } static struct request *elv_rqhash_find(request_queue_t *q, sector_t offset) { elevator_t *e = q->elevator; struct hlist_head *hash_list = &e->hash[ELV_HASH_FN(offset)]; struct hlist_node *entry, *next; struct request *rq; hlist_for_each_entry_safe(rq, entry, next, hash_list, hash) { BUG_ON(!ELV_ON_HASH(rq)); if (unlikely(!rq_mergeable(rq))) { __elv_rqhash_del(rq); continue; } if (rq_hash_key(rq) == offset) return rq; } return NULL; } /* * RB-tree support functions for inserting/lookup/removal of requests * in a sorted RB tree. */ struct request *elv_rb_add(struct rb_root *root, struct request *rq) { struct rb_node **p = &root->rb_node; struct rb_node *parent = NULL; struct request *__rq; while (*p) { parent = *p; __rq = rb_entry(parent, struct request, rb_node); if (rq->sector < __rq->sector) p = &(*p)->rb_left; else if (rq->sector > __rq->sector) p = &(*p)->rb_right; else return __rq; } rb_link_node(&rq->rb_node, parent, p); rb_insert_color(&rq->rb_node, root); return NULL; } EXPORT_SYMBOL(elv_rb_add); void elv_rb_del(struct rb_root *root, struct request *rq) { BUG_ON(RB_EMPTY_NODE(&rq->rb_node)); rb_erase(&rq->rb_node, root); RB_CLEAR_NODE(&rq->rb_node); } EXPORT_SYMBOL(elv_rb_del); struct request *elv_rb_find(struct rb_root *root, sector_t sector) { struct rb_node *n = root->rb_node; struct request *rq; while (n) { rq = rb_entry(n, struct request, rb_node); if (sector < rq->sector) n = n->rb_left; else if (sector > rq->sector) n = n->rb_right; else return rq; } return NULL; } EXPORT_SYMBOL(elv_rb_find); /* * Insert rq into dispatch queue of q. Queue lock must be held on * entry. rq is sort insted into the dispatch queue. To be used by * specific elevators. */ void elv_dispatch_sort(request_queue_t *q, struct request *rq) { sector_t boundary; struct list_head *entry; if (q->last_merge == rq) q->last_merge = NULL; elv_rqhash_del(q, rq); q->nr_sorted--; boundary = q->end_sector; list_for_each_prev(entry, &q->queue_head) { struct request *pos = list_entry_rq(entry); if (rq_data_dir(rq) != rq_data_dir(pos)) break; if (pos->cmd_flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED)) break; if (rq->sector >= boundary) { if (pos->sector < boundary) continue; } else { if (pos->sector >= boundary) break; } if (rq->sector >= pos->sector) break; } list_add(&rq->queuelist, entry); } EXPORT_SYMBOL(elv_dispatch_sort); /* * Insert rq into dispatch queue of q. Queue lock must be held on * entry. rq is added to the back of the dispatch queue. To be used by * specific elevators. */ void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) { if (q->last_merge == rq) q->last_merge = NULL; elv_rqhash_del(q, rq); q->nr_sorted--; q->end_sector = rq_end_sector(rq); q->boundary_rq = rq; list_add_tail(&rq->queuelist, &q->queue_head); } EXPORT_SYMBOL(elv_dispatch_add_tail); int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; struct request *__rq; int ret; /* * First try one-hit cache. */ if (q->last_merge) { ret = elv_try_merge(q->last_merge, bio); if (ret != ELEVATOR_NO_MERGE) { *req = q->last_merge; return ret; } } /* * See if our hash lookup can find a potential backmerge. */ __rq = elv_rqhash_find(q, bio->bi_sector); if (__rq && elv_rq_merge_ok(__rq, bio)) { *req = __rq; return ELEVATOR_BACK_MERGE; } if (e->ops->elevator_merge_fn) return e->ops->elevator_merge_fn(q, req, bio); return ELEVATOR_NO_MERGE; } void elv_merged_request(request_queue_t *q, struct request *rq, int type) { elevator_t *e = q->elevator; if (e->ops->elevator_merged_fn) e->ops->elevator_merged_fn(q, rq, type); if (type == ELEVATOR_BACK_MERGE) elv_rqhash_reposition(q, rq); q->last_merge = rq; } void elv_merge_requests(request_queue_t *q, struct request *rq, struct request *next) { elevator_t *e = q->elevator; if (e->ops->elevator_merge_req_fn) e->ops->elevator_merge_req_fn(q, rq, next); elv_rqhash_reposition(q, rq); elv_rqhash_del(q, next); q->nr_sorted--; q->last_merge = rq; } void elv_requeue_request(request_queue_t *q, struct request *rq) { /* * it already went through dequeue, we need to decrement the * in_flight count again */ if (blk_account_rq(rq)) { q->in_flight--; if (blk_sorted_rq(rq)) elv_deactivate_rq(q, rq); } rq->cmd_flags &= ~REQ_STARTED; elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE); } static void elv_drain_elevator(request_queue_t *q) { static int printed; while (q->elevator->ops->elevator_dispatch_fn(q, 1)) ; if (q->nr_sorted == 0) return; if (printed++ < 10) { printk(KERN_ERR "%s: forced dispatching is broken " "(nr_sorted=%u), please report this\n", q->elevator->elevator_type->elevator_name, q->nr_sorted); } } void elv_insert(request_queue_t *q, struct request *rq, int where) { struct list_head *pos; unsigned ordseq; int unplug_it = 1; blk_add_trace_rq(q, rq, BLK_TA_INSERT); rq->q = q; switch (where) { case ELEVATOR_INSERT_FRONT: rq->cmd_flags |= REQ_SOFTBARRIER; list_add(&rq->queuelist, &q->queue_head); break; case ELEVATOR_INSERT_BACK: rq->cmd_flags |= REQ_SOFTBARRIER; elv_drain_elevator(q); list_add_tail(&rq->queuelist, &q->queue_head); /* * We kick the queue here for the following reasons. * - The elevator might have returned NULL previously * to delay requests and returned them now. As the * queue wasn't empty before this request, ll_rw_blk * won't run the queue on return, resulting in hang. * - Usually, back inserted requests won't be merged * with anything. There's no point in delaying queue * processing. */ blk_remove_plug(q); q->request_fn(q); break; case ELEVATOR_INSERT_SORT: BUG_ON(!blk_fs_request(rq)); rq->cmd_flags |= REQ_SORTED; q->nr_sorted++; if (rq_mergeable(rq)) { elv_rqhash_add(q, rq); if (!q->last_merge) q->last_merge = rq; } /* * Some ioscheds (cfq) run q->request_fn directly, so * rq cannot be accessed after calling * elevator_add_req_fn. */ q->elevator->ops->elevator_add_req_fn(q, rq); break; case ELEVATOR_INSERT_REQUEUE: /* * If ordered flush isn't in progress, we do front * insertion; otherwise, requests should be requeued * in ordseq order. */ rq->cmd_flags |= REQ_SOFTBARRIER; /* * Most requeues happen because of a busy condition, * don't force unplug of the queue for that case. */ unplug_it = 0; if (q->ordseq == 0) { list_add(&rq->queuelist, &q->queue_head); break; } ordseq = blk_ordered_req_seq(rq); list_for_each(pos, &q->queue_head) { struct request *pos_rq = list_entry_rq(pos); if (ordseq <= blk_ordered_req_seq(pos_rq)) break; } list_add_tail(&rq->queuelist, pos); break; default: printk(KERN_ERR "%s: bad insertion point %d\n", __FUNCTION__, where); BUG(); } if (unplug_it && blk_queue_plugged(q)) { int nrq = q->rq.count[READ] + q->rq.count[WRITE] - q->in_flight; if (nrq >= q->unplug_thresh) __generic_unplug_device(q); } } void __elv_add_request(request_queue_t *q, struct request *rq, int where, int plug) { if (q->ordcolor) rq->cmd_flags |= REQ_ORDERED_COLOR; if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { /* * toggle ordered color */ if (blk_barrier_rq(rq)) q->ordcolor ^= 1; /* * barriers implicitly indicate back insertion */ if (where == ELEVATOR_INSERT_SORT) where = ELEVATOR_INSERT_BACK; /* * this request is scheduling boundary, update * end_sector */ if (blk_fs_request(rq)) { q->end_sector = rq_end_sector(rq); q->boundary_rq = rq; } } else if (!(rq->cmd_flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT) where = ELEVATOR_INSERT_BACK; if (plug) blk_plug_device(q); elv_insert(q, rq, where); } EXPORT_SYMBOL(__elv_add_request); void elv_add_request(request_queue_t *q, struct request *rq, int where, int plug) { unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); __elv_add_request(q, rq, where, plug); spin_unlock_irqrestore(q->queue_lock, flags); } EXPORT_SYMBOL(elv_add_request); static inline struct request *__elv_next_request(request_queue_t *q) { struct request *rq; while (1) { while (!list_empty(&q->queue_head)) { rq = list_entry_rq(q->queue_head.next); if (blk_do_ordered(q, &rq)) return rq; } if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) return NULL; } } struct request *elv_next_request(request_queue_t *q) { struct request *rq; int ret; while ((rq = __elv_next_request(q)) != NULL) { if (!(rq->cmd_flags & REQ_STARTED)) { /* * This is the first time the device driver * sees this request (possibly after * requeueing). Notify IO scheduler. */ if (blk_sorted_rq(rq)) elv_activate_rq(q, rq); /* * just mark as started even if we don't start * it, a request that has been delayed should * not be passed by new incoming requests */ rq->cmd_flags |= REQ_STARTED; blk_add_trace_rq(q, rq, BLK_TA_ISSUE); } if (!q->boundary_rq || q->boundary_rq == rq) { q->end_sector = rq_end_sector(rq); q->boundary_rq = NULL; } if ((rq->cmd_flags & REQ_DONTPREP) || !q->prep_rq_fn) break; ret = q->prep_rq_fn(q, rq); if (ret == BLKPREP_OK) { break; } else if (ret == BLKPREP_DEFER) { /* * the request may have been (partially) prepped. * we need to keep this request in the front to * avoid resource deadlock. REQ_STARTED will * prevent other fs requests from passing this one. */ rq = NULL; break; } else if (ret == BLKPREP_KILL) { int nr_bytes = rq->hard_nr_sectors << 9; if (!nr_bytes) nr_bytes = rq->data_len; blkdev_dequeue_request(rq); rq->cmd_flags |= REQ_QUIET; end_that_request_chunk(rq, 0, nr_bytes); end_that_request_last(rq, 0); } else { printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__, ret); break; } } return rq; } EXPORT_SYMBOL(elv_next_request); void elv_dequeue_request(request_queue_t *q, struct request *rq) { BUG_ON(list_empty(&rq->queuelist)); BUG_ON(ELV_ON_HASH(rq)); list_del_init(&rq->queuelist); /* * the time frame between a request being removed from the lists * and to it is freed is accounted as io that is in progress at * the driver side. */ if (blk_account_rq(rq)) q->in_flight++; } EXPORT_SYMBOL(elv_dequeue_request); int elv_queue_empty(request_queue_t *q) { elevator_t *e = q->elevator; if (!list_empty(&q->queue_head)) return 0; if (e->ops->elevator_queue_empty_fn) return e->ops->elevator_queue_empty_fn(q); return 1; } EXPORT_SYMBOL(elv_queue_empty); struct request *elv_latter_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; if (e->ops->elevator_latter_req_fn) return e->ops->elevator_latter_req_fn(q, rq); return NULL; } struct request *elv_former_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; if (e->ops->elevator_former_req_fn) return e->ops->elevator_former_req_fn(q, rq); return NULL; } int elv_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) { elevator_t *e = q->elevator; if (e->ops->elevator_set_req_fn) return e->ops->elevator_set_req_fn(q, rq, gfp_mask); rq->elevator_private = NULL; return 0; } void elv_put_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; if (e->ops->elevator_put_req_fn) e->ops->elevator_put_req_fn(rq); } int elv_may_queue(request_queue_t *q, int rw) { elevator_t *e = q->elevator; if (e->ops->elevator_may_queue_fn) return e->ops->elevator_may_queue_fn(q, rw); return ELV_MQUEUE_MAY; } void elv_completed_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; /* * request is released from the driver, io must be done */ if (blk_account_rq(rq)) { q->in_flight--; if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) e->ops->elevator_completed_req_fn(q, rq); } /* * Check if the queue is waiting for fs requests to be * drained for flush sequence. */ if (unlikely(q->ordseq)) { struct request *first_rq = list_entry_rq(q->queue_head.next); if (q->in_flight == 0 && blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN && blk_ordered_req_seq(first_rq) > QUEUE_ORDSEQ_DRAIN) { blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0); q->request_fn(q); } } } #define to_elv(atr) container_of((atr), struct elv_fs_entry, attr) static ssize_t elv_attr_show(struct kobject *kobj, struct attribute *attr, char *page) { elevator_t *e = container_of(kobj, elevator_t, kobj); struct elv_fs_entry *entry = to_elv(attr); ssize_t error; if (!entry->show) return -EIO; mutex_lock(&e->sysfs_lock); error = e->ops ? entry->show(e, page) : -ENOENT; mutex_unlock(&e->sysfs_lock); return error; } static ssize_t elv_attr_store(struct kobject *kobj, struct attribute *attr, const char *page, size_t length) { elevator_t *e = container_of(kobj, elevator_t, kobj); struct elv_fs_entry *entry = to_elv(attr); ssize_t error; if (!entry->store) return -EIO; mutex_lock(&e->sysfs_lock); error = e->ops ? entry->store(e, page, length) : -ENOENT; mutex_unlock(&e->sysfs_lock); return error; } static struct sysfs_ops elv_sysfs_ops = { .show = elv_attr_show, .store = elv_attr_store, }; static struct kobj_type elv_ktype = { .sysfs_ops = &elv_sysfs_ops, .release = elevator_release, }; int elv_register_queue(struct request_queue *q) { elevator_t *e = q->elevator; int error; e->kobj.parent = &q->kobj; error = kobject_add(&e->kobj); if (!error) { struct elv_fs_entry *attr = e->elevator_type->elevator_attrs; if (attr) { while (attr->attr.name) { if (sysfs_create_file(&e->kobj, &attr->attr)) break; attr++; } } kobject_uevent(&e->kobj, KOBJ_ADD); } return error; } static void __elv_unregister_queue(elevator_t *e) { kobject_uevent(&e->kobj, KOBJ_REMOVE); kobject_del(&e->kobj); } void elv_unregister_queue(struct request_queue *q) { if (q) __elv_unregister_queue(q->elevator); } int elv_register(struct elevator_type *e) { char *def = ""; spin_lock(&elv_list_lock); BUG_ON(elevator_find(e->elevator_name)); list_add_tail(&e->list, &elv_list); spin_unlock(&elv_list_lock); if (!strcmp(e->elevator_name, chosen_elevator) || (!*chosen_elevator && !strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED))) def = " (default)"; printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name, def); return 0; } EXPORT_SYMBOL_GPL(elv_register); void elv_unregister(struct elevator_type *e) { struct task_struct *g, *p; /* * Iterate every thread in the process to remove the io contexts. */ if (e->ops.trim) { read_lock(&tasklist_lock); do_each_thread(g, p) { task_lock(p); if (p->io_context) e->ops.trim(p->io_context); task_unlock(p); } while_each_thread(g, p); read_unlock(&tasklist_lock); } spin_lock(&elv_list_lock); list_del_init(&e->list); spin_unlock(&elv_list_lock); } EXPORT_SYMBOL_GPL(elv_unregister); /* * switch to new_e io scheduler. be careful not to introduce deadlocks - * we don't free the old io scheduler, before we have allocated what we * need for the new one. this way we have a chance of going back to the old * one, if the new one fails init for some reason. */ static int elevator_switch(request_queue_t *q, struct elevator_type *new_e) { elevator_t *old_elevator, *e; void *data; /* * Allocate new elevator */ e = elevator_alloc(q, new_e); if (!e) return 0; data = elevator_init_queue(q, e); if (!data) { kobject_put(&e->kobj); return 0; } /* * Turn on BYPASS and drain all requests w/ elevator private data */ spin_lock_irq(q->queue_lock); set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); elv_drain_elevator(q); while (q->rq.elvpriv) { blk_remove_plug(q); q->request_fn(q); spin_unlock_irq(q->queue_lock); msleep(10); spin_lock_irq(q->queue_lock); elv_drain_elevator(q); } /* * Remember old elevator. */ old_elevator = q->elevator; /* * attach and start new elevator */ elevator_attach(q, e, data); spin_unlock_irq(q->queue_lock); __elv_unregister_queue(old_elevator); if (elv_register_queue(q)) goto fail_register; /* * finally exit old elevator and turn off BYPASS. */ elevator_exit(old_elevator); clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); return 1; fail_register: /* * switch failed, exit the new io scheduler and reattach the old * one again (along with re-adding the sysfs dir) */ elevator_exit(e); q->elevator = old_elevator; elv_register_queue(q); clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); return 0; } ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count) { char elevator_name[ELV_NAME_MAX]; size_t len; struct elevator_type *e; elevator_name[sizeof(elevator_name) - 1] = '\0'; strncpy(elevator_name, name, sizeof(elevator_name) - 1); len = strlen(elevator_name); if (len && elevator_name[len - 1] == '\n') elevator_name[len - 1] = '\0'; e = elevator_get(elevator_name); if (!e) { printk(KERN_ERR "elevator: type %s not found\n", elevator_name); return -EINVAL; } if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) { elevator_put(e); return count; } if (!elevator_switch(q, e)) printk(KERN_ERR "elevator: switch to %s failed\n",elevator_name); return count; } ssize_t elv_iosched_show(request_queue_t *q, char *name) { elevator_t *e = q->elevator; struct elevator_type *elv = e->elevator_type; struct list_head *entry; int len = 0; spin_lock(&elv_list_lock); list_for_each(entry, &elv_list) { struct elevator_type *__e; __e = list_entry(entry, struct elevator_type, list); if (!strcmp(elv->elevator_name, __e->elevator_name)) len += sprintf(name+len, "[%s] ", elv->elevator_name); else len += sprintf(name+len, "%s ", __e->elevator_name); } spin_unlock(&elv_list_lock); len += sprintf(len+name, "\n"); return len; } struct request *elv_rb_former_request(request_queue_t *q, struct request *rq) { struct rb_node *rbprev = rb_prev(&rq->rb_node); if (rbprev) return rb_entry_rq(rbprev); return NULL; } EXPORT_SYMBOL(elv_rb_former_request); struct request *elv_rb_latter_request(request_queue_t *q, struct request *rq) { struct rb_node *rbnext = rb_next(&rq->rb_node); if (rbnext) return rb_entry_rq(rbnext); return NULL; } EXPORT_SYMBOL(elv_rb_latter_request);


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