zpool: remove zpool_evict()

Remove zpool_evict() helper function.  As zbud is currently the only
zpool implementation that supports eviction, add zpool and zpool_ops
references to struct zbud_pool and directly call zpool_ops->evict(zpool,
handle) on eviction.

Currently zpool provides the zpool_evict helper which locks the zpool
list lock and searches through all pools to find the specific one
matching the caller, and call the corresponding zpool_ops->evict
function.  However, this is unnecessary, as the zbud pool can simply
keep a reference to the zpool that created it, as well as the zpool_ops,
and directly call the zpool_ops->evict function, when it needs to evict
a page.  This avoids a spinlock and list search in zpool for each
eviction.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 19 insertions, 4 deletions

diff --git a/mm/zbud.c b/mm/zbud.c
index 2ee4e45..f3bf6f7 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -97,6 +97,10 @@ struct zbud_pool {
 	struct list_head lru;
 	u64 pages_nr;
 	struct zbud_ops *ops;
+#ifdef CONFIG_ZPOOL
+	struct zpool *zpool;
+	struct zpool_ops *zpool_ops;
+#endif
 };
 
 /*
@@ -123,7 +127,10 @@ struct zbud_header {
 
 static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
 {
-	return zpool_evict(pool, handle);
+	if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
+		return pool->zpool_ops->evict(pool->zpool, handle);
+	else
+		return -ENOENT;
 }
 
 static struct zbud_ops zbud_zpool_ops = {
@@ -131,9 +138,17 @@ static struct zbud_ops zbud_zpool_ops = {
 };
 
 static void *zbud_zpool_create(char *name, gfp_t gfp,
-			struct zpool_ops *zpool_ops)
+			       struct zpool_ops *zpool_ops,
+			       struct zpool *zpool)
 {
-	return zbud_create_pool(gfp, zpool_ops ? &zbud_zpool_ops : NULL);
+	struct zbud_pool *pool;
+
+	pool = zbud_create_pool(gfp, zpool_ops ? &zbud_zpool_ops : NULL);
+	if (pool) {
+		pool->zpool = zpool;
+		pool->zpool_ops = zpool_ops;
+	}
+	return pool;
 }
 
 static void zbud_zpool_destroy(void *pool)
@@ -292,7 +307,7 @@ struct zbud_pool *zbud_create_pool(gfp_t gfp, struct zbud_ops *ops)
 	struct zbud_pool *pool;
 	int i;
 
-	pool = kmalloc(sizeof(struct zbud_pool), gfp);
+	pool = kzalloc(sizeof(struct zbud_pool), gfp);
 	if (!pool)
 		return NULL;
 	spin_lock_init(&pool->lock);