summaryrefslogtreecommitdiff
path: root/drivers/xen
diff options
context:
space:
mode:
authorJuergen Gross <jgross@suse.com>2020-12-07 08:31:22 +0100
committerJuergen Gross <jgross@suse.com>2020-12-09 10:31:37 +0100
commitca33479cc7be2c9b5f8be078c8bf3ac26b7d6186 (patch)
tree8877168fff59f8955f29ddaf37a0ac6a0cb3d9fd /drivers/xen
parenta68a0262abdaa251e12c53715f48e698a18ef402 (diff)
xen: add helpers for caching grant mapping pages
Instead of having similar helpers in multiple backend drivers use common helpers for caching pages allocated via gnttab_alloc_pages(). Make use of those helpers in blkback and scsiback. Cc: <stable@vger.kernel.org> # 5.9 Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovksy@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/grant-table.c72
-rw-r--r--drivers/xen/xen-scsiback.c60
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);
}