zpool: clean out dead code

There is a lot of provision for flexibility that isn't actually needed or
used.  Zswap (the only zpool user) always passes zpool_ops with an .evict
method set.  The backends who reclaim only do so for zswap, so they can
also directly call zpool_ops without indirection or checks.

Finally, there is no need to check the retries parameters and bail with
-EINVAL in the reclaim function, when that's called just a few lines below
with a hard-coded 8.  There is no need to duplicate the evictable and
sleep_mapped attrs from the driver in zpool_ops.

Link: https://lkml.kernel.org/r/20221128191616.1261026-3-nphamcs@gmail.com
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/z3fold.c b/mm/z3fold.c
index cf71da1..a4de0c3 100644 (file)
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -68,9 +68,6 @@
  * Structures
 *****************/
 struct z3fold_pool;
-struct z3fold_ops {
-       int (*evict)(struct z3fold_pool *pool, unsigned long handle);
-};
 
 enum buddy {
        HEADLESS = 0,
@@ -138,8 +135,6 @@ struct z3fold_header {
  * @stale:     list of pages marked for freeing
  * @pages_nr:  number of z3fold pages in the pool.
  * @c_handle:  cache for z3fold_buddy_slots allocation
- * @ops:       pointer to a structure of user defined operations specified at
- *             pool creation time.
  * @zpool:     zpool driver
  * @zpool_ops: zpool operations structure with an evict callback
  * @compact_wq:        workqueue for page layout background optimization
@@ -158,7 +153,6 @@ struct z3fold_pool {
        struct list_head stale;
        atomic64_t pages_nr;
        struct kmem_cache *c_handle;
-       const struct z3fold_ops *ops;
        struct zpool *zpool;
        const struct zpool_ops *zpool_ops;
        struct workqueue_struct *compact_wq;
@@ -907,13 +901,11 @@ out_fail:
  * z3fold_create_pool() - create a new z3fold pool
  * @name:      pool name
  * @gfp:       gfp flags when allocating the z3fold pool structure
- * @ops:       user-defined operations for the z3fold pool
  *
  * Return: pointer to the new z3fold pool or NULL if the metadata allocation
  * failed.
  */
-static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
-               const struct z3fold_ops *ops)
+static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp)
 {
        struct z3fold_pool *pool = NULL;
        int i, cpu;
@@ -949,7 +941,6 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
        if (!pool->release_wq)
                goto out_wq;
        INIT_WORK(&pool->work, free_pages_work);
-       pool->ops = ops;
        return pool;
 
 out_wq:
@@ -1230,10 +1221,6 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
        slots.pool = (unsigned long)pool | (1 << HANDLES_NOFREE);
 
        spin_lock(&pool->lock);
-       if (!pool->ops || !pool->ops->evict || retries == 0) {
-               spin_unlock(&pool->lock);
-               return -EINVAL;
-       }
        for (i = 0; i < retries; i++) {
                if (list_empty(&pool->lru)) {
                        spin_unlock(&pool->lock);
@@ -1319,17 +1306,17 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
                }
                /* Issue the eviction callback(s) */
                if (middle_handle) {
-                       ret = pool->ops->evict(pool, middle_handle);
+                       ret = pool->zpool_ops->evict(pool->zpool, middle_handle);
                        if (ret)
                                goto next;
                }
                if (first_handle) {
-                       ret = pool->ops->evict(pool, first_handle);
+                       ret = pool->zpool_ops->evict(pool->zpool, first_handle);
                        if (ret)
                                goto next;
                }
                if (last_handle) {
-                       ret = pool->ops->evict(pool, last_handle);
+                       ret = pool->zpool_ops->evict(pool->zpool, last_handle);
                        if (ret)
                                goto next;
                }
@@ -1593,26 +1580,13 @@ static const struct movable_operations z3fold_mops = {
  * zpool
  ****************/
 
-static int z3fold_zpool_evict(struct z3fold_pool *pool, unsigned long handle)
-{
-       if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
-               return pool->zpool_ops->evict(pool->zpool, handle);
-       else
-               return -ENOENT;
-}
-
-static const struct z3fold_ops z3fold_zpool_ops = {
-       .evict =        z3fold_zpool_evict
-};
-
 static void *z3fold_zpool_create(const char *name, gfp_t gfp,
                               const struct zpool_ops *zpool_ops,
                               struct zpool *zpool)
 {
        struct z3fold_pool *pool;
 
-       pool = z3fold_create_pool(name, gfp,
-                               zpool_ops ? &z3fold_zpool_ops : NULL);
+       pool = z3fold_create_pool(name, gfp);
        if (pool) {
                pool->zpool = zpool;
                pool->zpool_ops = zpool_ops;

diff --git a/mm/zbud.c b/mm/zbud.c
index 6348932..3acd261 100644 (file)
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -74,10 +74,6 @@
 
 struct zbud_pool;
 
-struct zbud_ops {
-       int (*evict)(struct zbud_pool *pool, unsigned long handle);
-};
-
 /**
  * struct zbud_pool - stores metadata for each zbud pool
  * @lock:      protects all pool fields and first|last_chunk fields of any
@@ -90,8 +86,6 @@ struct zbud_ops {
  * @lru:       list tracking the zbud pages in LRU order by most recently
  *             added buddy.
  * @pages_nr:  number of zbud pages in the pool.
- * @ops:       pointer to a structure of user defined operations specified at
- *             pool creation time.
  * @zpool:     zpool driver
  * @zpool_ops: zpool operations structure with an evict callback
  *
@@ -110,7 +104,6 @@ struct zbud_pool {
        };
        struct list_head lru;
        u64 pages_nr;
-       const struct zbud_ops *ops;
        struct zpool *zpool;
        const struct zpool_ops *zpool_ops;
 };
@@ -212,12 +205,11 @@ static int num_free_chunks(struct zbud_header *zhdr)
 /**
  * zbud_create_pool() - create a new zbud pool
  * @gfp:       gfp flags when allocating the zbud pool structure
- * @ops:       user-defined operations for the zbud pool
  *
  * Return: pointer to the new zbud pool or NULL if the metadata allocation
  * failed.
  */
-static struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops)
+static struct zbud_pool *zbud_create_pool(gfp_t gfp)
 {
        struct zbud_pool *pool;
        int i;
@@ -231,7 +223,6 @@ static struct zbud_pool *zbud_create_pool(gfp_t gfp, const struct zbud_ops *ops)
        INIT_LIST_HEAD(&pool->buddied);
        INIT_LIST_HEAD(&pool->lru);
        pool->pages_nr = 0;
-       pool->ops = ops;
        return pool;
 }
 
@@ -419,8 +410,7 @@ static int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries)
        unsigned long first_handle = 0, last_handle = 0;
 
        spin_lock(&pool->lock);
-       if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) ||
-                       retries == 0) {
+       if (list_empty(&pool->lru)) {
                spin_unlock(&pool->lock);
                return -EINVAL;
        }
@@ -444,12 +434,12 @@ static int zbud_reclaim_page(struct zbud_pool *pool, unsigned int retries)
 
                /* Issue the eviction callback(s) */
                if (first_handle) {
-                       ret = pool->ops->evict(pool, first_handle);
+                       ret = pool->zpool_ops->evict(pool->zpool, first_handle);
                        if (ret)
                                goto next;
                }
                if (last_handle) {
-                       ret = pool->ops->evict(pool, last_handle);
+                       ret = pool->zpool_ops->evict(pool->zpool, last_handle);
                        if (ret)
                                goto next;
                }
@@ -524,25 +514,13 @@ static u64 zbud_get_pool_size(struct zbud_pool *pool)
  * zpool
  ****************/
 
-static int zbud_zpool_evict(struct zbud_pool *pool, unsigned long handle)
-{
-       if (pool->zpool && pool->zpool_ops && pool->zpool_ops->evict)
-               return pool->zpool_ops->evict(pool->zpool, handle);
-       else
-               return -ENOENT;
-}
-
-static const struct zbud_ops zbud_zpool_ops = {
-       .evict =        zbud_zpool_evict
-};
-
 static void *zbud_zpool_create(const char *name, gfp_t gfp,
                               const struct zpool_ops *zpool_ops,
                               struct zpool *zpool)
 {
        struct zbud_pool *pool;
 
-       pool = zbud_create_pool(gfp, zpool_ops ? &zbud_zpool_ops : NULL);
+       pool = zbud_create_pool(gfp);
        if (pool) {
                pool->zpool = zpool;
                pool->zpool_ops = zpool_ops;

diff --git a/mm/zpool.c b/mm/zpool.c
index f46c0d5..571f5c5 100644 (file)
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -21,9 +21,6 @@
 struct zpool {
        struct zpool_driver *driver;
        void *pool;
-       const struct zpool_ops *ops;
-       bool evictable;
-       bool can_sleep_mapped;
 };
 
 static LIST_HEAD(drivers_head);
@@ -177,9 +174,6 @@ struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp,
 
        zpool->driver = driver;
        zpool->pool = driver->create(name, gfp, ops, zpool);
-       zpool->ops = ops;
-       zpool->evictable = driver->shrink && ops && ops->evict;
-       zpool->can_sleep_mapped = driver->sleep_mapped;
 
        if (!zpool->pool) {
                pr_err("couldn't create %s pool\n", type);
@@ -380,7 +374,7 @@ u64 zpool_get_total_size(struct zpool *zpool)
  */
 bool zpool_evictable(struct zpool *zpool)
 {
-       return zpool->evictable;
+       return zpool->driver->shrink;
 }
 
 /**
@@ -398,7 +392,7 @@ bool zpool_evictable(struct zpool *zpool)
  */
 bool zpool_can_sleep_mapped(struct zpool *zpool)
 {
-       return zpool->can_sleep_mapped;
+       return zpool->driver->sleep_mapped;
 }
 
 MODULE_LICENSE("GPL");