/* * Functions related to sysfs handling */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/bio.h> #include <linux/blkdev.h> #include <linux/blktrace_api.h> #include "blk.h" struct queue_sysfs_entry { struct attribute attr; ssize_t (*show)(struct request_queue *, char *); ssize_t (*store)(struct request_queue *, const char *, size_t); }; static ssize_t queue_var_show(unsigned int var, char *page) { return sprintf(page, "%d\n", var); } static ssize_t queue_var_store(unsigned long *var, const char *page, size_t count) { char *p = (char *) page; *var = simple_strtoul(p, &p, 10); return count; } static ssize_t queue_requests_show(struct request_queue *q, char *page) { return queue_var_show(q->nr_requests, (page)); } static ssize_t queue_requests_store(struct request_queue *q, const char *page, size_t count) { struct request_list *rl = &q->rq; unsigned long nr; int ret = queue_var_store(&nr, page, count); if (nr < BLKDEV_MIN_RQ) nr = BLKDEV_MIN_RQ; spin_lock_irq(q->queue_lock); q->nr_requests = nr; blk_queue_congestion_threshold(q); if (rl->count[READ] >= queue_congestion_on_threshold(q)) blk_set_queue_congested(q, READ); else if (rl->count[READ] < queue_congestion_off_threshold(q)) blk_clear_queue_congested(q, READ); if (rl->count[WRITE] >= queue_congestion_on_threshold(q)) blk_set_queue_congested(q, WRITE); else if (rl->count[WRITE] < queue_congestion_off_threshold(q)) blk_clear_queue_congested(q, WRITE); if (rl->count[READ] >= q->nr_requests) { blk_set_queue_full(q, READ); } else if (rl->count[READ]+1 <= q->nr_requests) { blk_clear_queue_full(q, READ); wake_up(&rl->wait[READ]); } if (rl->count[WRITE] >= q->nr_requests) { blk_set_queue_full(q, WRITE); } else if (rl->count[WRITE]+1 <= q->nr_requests) { blk_clear_queue_full(q, WRITE); wake_up(&rl->wait[WRITE]); } spin_unlock_irq(q->queue_lock); return ret; } static ssize_t queue_ra_show(struct request_queue *q, char *page) { int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10); return queue_var_show(ra_kb, (page)); } static ssize_t queue_ra_store(struct request_queue *q, const char *page, size_t count) { unsigned long ra_kb; ssize_t ret = queue_var_store(&ra_kb, page, count); spin_lock_irq(q->queue_lock); q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10); spin_unlock_irq(q->queue_lock); return ret; } static ssize_t queue_max_sectors_show(struct request_queue *q, char *page) { int max_sectors_kb = q->max_sectors >> 1; return queue_var_show(max_sectors_kb, (page)); } static ssize_t queue_hw_sector_size_show(struct request_queue *q, char *page) { return queue_var_show(q->hardsect_size, page); } static ssize_t queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) { unsigned long max_sectors_kb, max_hw_sectors_kb = q->max_hw_sectors >> 1, page_kb = 1 << (PAGE_CACHE_SHIFT - 10); ssize_t ret = queue_var_store(&max_sectors_kb, page, count); if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) return -EINVAL; /* * Take the queue lock to update the readahead and max_sectors * values synchronously: */ spin_lock_irq(q->queue_lock); q->max_sectors = max_sectors_kb << 1; spin_unlock_irq(q->queue_lock); return ret; } static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page) { int max_hw_sectors_kb = q->max_hw_sectors >> 1; return queue_var_show(max_hw_sectors_kb, (page)); } static struct queue_sysfs_entry queue_requests_entry = { .attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR }, .show = queue_requests_show, .store = queue_requests_store, }; static struct queue_sysfs_entry queue_ra_entry = { .attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR }, .show = queue_ra_show, .store = queue_ra_store, }; static struct queue_sysfs_entry queue_max_sectors_entry = { .attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR }, .show = queue_max_sectors_show, .store = queue_max_sectors_store, }; static struct queue_sysfs_entry queue_max_hw_sectors_entry = { .attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO }, .show = queue_max_hw_sectors_show, }; static struct queue_sysfs_entry queue_iosched_entry = { .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR }, .show = elv_iosched_show, .store = elv_iosched_store, }; static struct queue_sysfs_entry queue_hw_sector_size_entry = { .attr = {.name = "hw_sector_size", .mode = S_IRUGO }, .show = queue_hw_sector_size_show, }; static struct attribute *default_attrs[] = { &queue_requests_entry.attr, &queue_ra_entry.attr, &queue_max_hw_sectors_entry.attr, &queue_max_sectors_entry.attr, &queue_iosched_entry.attr, &queue_hw_sector_size_entry.attr, NULL, }; #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr) static ssize_t queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) { struct queue_sysfs_entry *entry = to_queue(attr); struct request_queue *q = container_of(kobj, struct request_queue, kobj); ssize_t res; if (!entry->show) return -EIO; mutex_lock(&q->sysfs_lock); if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { mutex_unlock(&q->sysfs_lock); return -ENOENT; } res = entry->show(q, page); mutex_unlock(&q->sysfs_lock); return res; } static ssize_t queue_attr_store(struct kobject *kobj, struct attribute *attr, const char *page, size_t length) { struct queue_sysfs_entry *entry = to_queue(attr); struct request_queue *q; ssize_t res; if (!entry->store) return -EIO; q = container_of(kobj, struct request_queue, kobj); mutex_lock(&q->sysfs_lock); if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) { mutex_unlock(&q->sysfs_lock); return -ENOENT; } res = entry->store(q, page, length); mutex_unlock(&q->sysfs_lock); return res; } /** * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed * @kobj: the kobj belonging of the request queue to be released * * Description: * blk_cleanup_queue is the pair to blk_init_queue() or * blk_queue_make_request(). It should be called when a request queue is * being released; typically when a block device is being de-registered. * Currently, its primary task it to free all the &struct request * structures that were allocated to the queue and the queue itself. * * Caveat: * Hopefully the low level driver will have finished any * outstanding requests first... **/ static void blk_release_queue(struct kobject *kobj) { struct request_queue *q = container_of(kobj, struct request_queue, kobj); struct request_list *rl = &q->rq; blk_sync_queue(q); if (rl->rq_pool) mempool_destroy(rl->rq_pool); if (q->queue_tags) __blk_queue_free_tags(q); blk_trace_shutdown(q); bdi_destroy(&q->backing_dev_info); kmem_cache_free(blk_requestq_cachep, q); } static struct sysfs_ops queue_sysfs_ops = { .show = queue_attr_show, .store = queue_attr_store, }; struct kobj_type blk_queue_ktype = { .sysfs_ops = &queue_sysfs_ops, .default_attrs = default_attrs, .release = blk_release_queue, }; int blk_register_queue(struct gendisk *disk) { int ret; struct request_queue *q = disk->queue; if (WARN_ON(!q)) return -ENXIO; if (!q->request_fn) return 0; ret = kobject_add(&q->kobj, kobject_get(&disk->dev.kobj), "%s", "queue"); if (ret < 0) return ret; kobject_uevent(&q->kobj, KOBJ_ADD); ret = elv_register_queue(q); if (ret) { kobject_uevent(&q->kobj, KOBJ_REMOVE); kobject_del(&q->kobj); return ret; } return 0; } void blk_unregister_queue(struct gendisk *disk) { struct request_queue *q = disk->queue; if (WARN_ON(!q)) return; if (q->request_fn) { elv_unregister_queue(q); kobject_uevent(&q->kobj, KOBJ_REMOVE); kobject_del(&q->kobj); kobject_put(&disk->dev.kobj); } }