diff options
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/grant-table.c | 72 | ||||
| -rw-r--r-- | drivers/xen/xen-scsiback.c | 60 |
2 files changed, 83 insertions, 49 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 523dcdf39cc9..e2e42912f241 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -813,6 +813,78 @@ int gnttab_alloc_pages(int nr_pages, struct page **pages) } EXPORT_SYMBOL_GPL(gnttab_alloc_pages); +void gnttab_page_cache_init(struct gnttab_page_cache *cache) +{ + spin_lock_init(&cache->lock); + INIT_LIST_HEAD(&cache->pages); + cache->num_pages = 0; +} +EXPORT_SYMBOL_GPL(gnttab_page_cache_init); + +int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page) +{ + unsigned long flags; + + spin_lock_irqsave(&cache->lock, flags); + + if (list_empty(&cache->pages)) { + spin_unlock_irqrestore(&cache->lock, flags); + return gnttab_alloc_pages(1, page); + } + + page[0] = list_first_entry(&cache->pages, struct page, lru); + list_del(&page[0]->lru); + cache->num_pages--; + + spin_unlock_irqrestore(&cache->lock, flags); + + return 0; +} +EXPORT_SYMBOL_GPL(gnttab_page_cache_get); + +void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page, + unsigned int num) +{ + unsigned long flags; + unsigned int i; + + spin_lock_irqsave(&cache->lock, flags); + + for (i = 0; i < num; i++) + list_add(&page[i]->lru, &cache->pages); + cache->num_pages += num; + + spin_unlock_irqrestore(&cache->lock, flags); +} +EXPORT_SYMBOL_GPL(gnttab_page_cache_put); + +void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num) +{ + struct page *page[10]; + unsigned int i = 0; + unsigned long flags; + + spin_lock_irqsave(&cache->lock, flags); + + while (cache->num_pages > num) { + page[i] = list_first_entry(&cache->pages, struct page, lru); + list_del(&page[i]->lru); + cache->num_pages--; + if (++i == ARRAY_SIZE(page)) { + spin_unlock_irqrestore(&cache->lock, flags); + gnttab_free_pages(i, page); + i = 0; + spin_lock_irqsave(&cache->lock, flags); + } + } + + spin_unlock_irqrestore(&cache->lock, flags); + + if (i != 0) + gnttab_free_pages(i, page); +} +EXPORT_SYMBOL_GPL(gnttab_page_cache_shrink); + void gnttab_pages_clear_private(int nr_pages, struct page **pages) { int i; diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c index 4acc4e899600..862162dca33c 100644 --- a/drivers/xen/xen-scsiback.c +++ b/drivers/xen/xen-scsiback.c @@ -99,6 +99,8 @@ struct vscsibk_info { struct list_head v2p_entry_lists; wait_queue_head_t waiting_to_free; + + struct gnttab_page_cache free_pages; }; /* theoretical maximum of grants for one request */ @@ -188,10 +190,6 @@ module_param_named(max_buffer_pages, scsiback_max_buffer_pages, int, 0644); MODULE_PARM_DESC(max_buffer_pages, "Maximum number of free pages to keep in backend buffer"); -static DEFINE_SPINLOCK(free_pages_lock); -static int free_pages_num; -static LIST_HEAD(scsiback_free_pages); - /* Global spinlock to protect scsiback TPG list */ static DEFINE_MUTEX(scsiback_mutex); static LIST_HEAD(scsiback_list); @@ -207,41 +205,6 @@ static void scsiback_put(struct vscsibk_info *info) wake_up(&info->waiting_to_free); } -static void put_free_pages(struct page **page, int num) -{ - unsigned long flags; - int i = free_pages_num + num, n = num; - - if (num == 0) - return; - if (i > scsiback_max_buffer_pages) { - n = min(num, i - scsiback_max_buffer_pages); - gnttab_free_pages(n, page + num - n); - n = num - n; - } - spin_lock_irqsave(&free_pages_lock, flags); - for (i = 0; i < n; i++) - list_add(&page[i]->lru, &scsiback_free_pages); - free_pages_num += n; - spin_unlock_irqrestore(&free_pages_lock, flags); -} - -static int get_free_page(struct page **page) -{ - unsigned long flags; - - spin_lock_irqsave(&free_pages_lock, flags); - if (list_empty(&scsiback_free_pages)) { - spin_unlock_irqrestore(&free_pages_lock, flags); - return gnttab_alloc_pages(1, page); - } - page[0] = list_first_entry(&scsiback_free_pages, struct page, lru); - list_del(&page[0]->lru); - free_pages_num--; - spin_unlock_irqrestore(&free_pages_lock, flags); - return 0; -} - static unsigned long vaddr_page(struct page *page) { unsigned long pfn = page_to_pfn(page); @@ -302,7 +265,8 @@ static void scsiback_fast_flush_area(struct vscsibk_pend *req) BUG_ON(err); } - put_free_pages(req->pages, req->n_grants); + gnttab_page_cache_put(&req->info->free_pages, req->pages, + req->n_grants); req->n_grants = 0; } @@ -445,8 +409,8 @@ static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req, struct vscsibk_info *info = pending_req->info; for (i = 0; i < cnt; i++) { - if (get_free_page(pg + mapcount)) { - put_free_pages(pg, mapcount); + if (gnttab_page_cache_get(&info->free_pages, pg + mapcount)) { + gnttab_page_cache_put(&info->free_pages, pg, mapcount); pr_err("no grant page\n"); return -ENOMEM; } @@ -796,6 +760,8 @@ static int scsiback_do_cmd_fn(struct vscsibk_info *info, cond_resched(); } + gnttab_page_cache_shrink(&info->free_pages, scsiback_max_buffer_pages); + RING_FINAL_CHECK_FOR_REQUESTS(&info->ring, more_to_do); return more_to_do; } @@ -1233,6 +1199,8 @@ static int scsiback_remove(struct xenbus_device *dev) scsiback_release_translation_entry(info); + gnttab_page_cache_shrink(&info->free_pages, 0); + dev_set_drvdata(&dev->dev, NULL); return 0; @@ -1263,6 +1231,7 @@ static int scsiback_probe(struct xenbus_device *dev, info->irq = 0; INIT_LIST_HEAD(&info->v2p_entry_lists); spin_lock_init(&info->v2p_lock); + gnttab_page_cache_init(&info->free_pages); err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u", SG_ALL); @@ -1879,13 +1848,6 @@ out: static void __exit scsiback_exit(void) { - struct page *page; - - while (free_pages_num) { - if (get_free_page(&page)) - BUG(); - gnttab_free_pages(1, &page); - } target_unregister_template(&scsiback_ops); xenbus_unregister_driver(&scsiback_driver); } |