1 files changed, 70 insertions, 105 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 021d64768a55..a973d268c157 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -17,6 +17,7 @@
 #include <linux/prefetch.h>
 #include <linux/buffer_head.h> /* for inode_has_buffers */
 #include <linux/ratelimit.h>
+#include <linux/list_lru.h>
 #include "internal.h"
 
 /*
@@ -24,7 +25,7 @@
  *
  * inode->i_lock protects:
  *   inode->i_state, inode->i_hash, __iget()
- * inode->i_sb->s_inode_lru_lock protects:
+ * Inode LRU list locks protect:
  *   inode->i_sb->s_inode_lru, inode->i_lru
  * inode_sb_list_lock protects:
  *   sb->s_inodes, inode->i_sb_list
@@ -37,7 +38,7 @@
  *
  * inode_sb_list_lock
  *   inode->i_lock
- *     inode->i_sb->s_inode_lru_lock
+ *     Inode LRU list locks
  *
  * bdi->wb.list_lock
  *   inode->i_lock
@@ -401,13 +402,8 @@ EXPORT_SYMBOL(ihold);
 
 static void inode_lru_list_add(struct inode *inode)
 {
-        spin_lock(&inode->i_sb->s_inode_lru_lock);
-        if (list_empty(&inode->i_lru)) {
-                list_add(&inode->i_lru, &inode->i_sb->s_inode_lru);
-                inode->i_sb->s_nr_inodes_unused++;
+        if (list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru))
                 this_cpu_inc(nr_unused);
-        }
-        spin_unlock(&inode->i_sb->s_inode_lru_lock);
 }
 
 /*
@@ -425,13 +421,9 @@ void inode_add_lru(struct inode *inode)
 
 static void inode_lru_list_del(struct inode *inode)
 {
-        spin_lock(&inode->i_sb->s_inode_lru_lock);
-        if (!list_empty(&inode->i_lru)) {
-                list_del_init(&inode->i_lru);
-                inode->i_sb->s_nr_inodes_unused--;
+
+        if (list_lru_del(&inode->i_sb->s_inode_lru, &inode->i_lru))
                 this_cpu_dec(nr_unused);
-        }
-        spin_unlock(&inode->i_sb->s_inode_lru_lock);
 }
 
 /**
@@ -675,24 +667,8 @@ int invalidate_inodes(struct super_block *sb, bool kill_dirty)
         return busy;
 }
 
-static int can_unuse(struct inode *inode)
-{
-        if (inode->i_state & ~I_REFERENCED)
-                return 0;
-        if (inode_has_buffers(inode))
-                return 0;
-        if (atomic_read(&inode->i_count))
-                return 0;
-        if (inode->i_data.nrpages)
-                return 0;
-        return 1;
-}
-
 /*
- * Walk the superblock inode LRU for freeable inodes and attempt to free them.
- * This is called from the superblock shrinker function with a number of inodes
- * to trim from the LRU. Inodes to be freed are moved to a temporary list and
- * then are freed outside inode_lock by dispose_list().
+ * Isolate the inode from the LRU in preparation for freeing it.
  *
  * Any inodes which are pinned purely because of attached pagecache have their
  * pagecache removed.  If the inode has metadata buffers attached to
@@ -706,90 +682,79 @@ static int can_unuse(struct inode *inode)
  * LRU does not have strict ordering. Hence we don't want to reclaim inodes
  * with this flag set because they are the inodes that are out of order.
  */
-long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan)
+static enum lru_status
+inode_lru_isolate(struct list_head *item, spinlock_t *lru_lock, void *arg)
 {
-        LIST_HEAD(freeable);
-        long nr_scanned;
-        long freed = 0;
-        unsigned long reap = 0;
+        struct list_head *freeable = arg;
+        struct inode    *inode = container_of(item, struct inode, i_lru);
 
-        spin_lock(&sb->s_inode_lru_lock);
-        for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) {
-                struct inode *inode;
+        /*
+         * we are inverting the lru lock/inode->i_lock here, so use a trylock.
+         * If we fail to get the lock, just skip it.
+         */
+        if (!spin_trylock(&inode->i_lock))
+                return LRU_SKIP;
 
-                if (list_empty(&sb->s_inode_lru))
-                        break;
+        /*
+         * Referenced or dirty inodes are still in use. Give them another pass
+         * through the LRU as we canot reclaim them now.
+         */
+        if (atomic_read(&inode->i_count) ||
+            (inode->i_state & ~I_REFERENCED)) {
+                list_del_init(&inode->i_lru);
+                spin_unlock(&inode->i_lock);
+                this_cpu_dec(nr_unused);
+                return LRU_REMOVED;
+        }
 
-                inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru);
+        /* recently referenced inodes get one more pass */
+        if (inode->i_state & I_REFERENCED) {
+                inode->i_state &= ~I_REFERENCED;
+                spin_unlock(&inode->i_lock);
+                return LRU_ROTATE;
+        }
 
-                /*
-                 * we are inverting the sb->s_inode_lru_lock/inode->i_lock here,
-                 * so use a trylock. If we fail to get the lock, just move the
-                 * inode to the back of the list so we don't spin on it.
-                 */
-                if (!spin_trylock(&inode->i_lock)) {
-                        list_move(&inode->i_lru, &sb->s_inode_lru);
-                        continue;
+        if (inode_has_buffers(inode) || inode->i_data.nrpages) {
+                __iget(inode);
+                spin_unlock(&inode->i_lock);
+                spin_unlock(lru_lock);
+                if (remove_inode_buffers(inode)) {
+                        unsigned long reap;
+                        reap = invalidate_mapping_pages(&inode->i_data, 0, -1);
+                        if (current_is_kswapd())
+                                __count_vm_events(KSWAPD_INODESTEAL, reap);
+                        else
+                                __count_vm_events(PGINODESTEAL, reap);
+                        if (current->reclaim_state)
+                                current->reclaim_state->reclaimed_slab += reap;
                 }
+                iput(inode);
+                spin_lock(lru_lock);
+                return LRU_RETRY;
+        }
 
-                /*
-                 * Referenced or dirty inodes are still in use. Give them
-                 * another pass through the LRU as we canot reclaim them now.
-                 */
-                if (atomic_read(&inode->i_count) ||
-                    (inode->i_state & ~I_REFERENCED)) {
-                        list_del_init(&inode->i_lru);
-                        spin_unlock(&inode->i_lock);
-                        sb->s_nr_inodes_unused--;
-                        this_cpu_dec(nr_unused);
-                        continue;
-                }
+        WARN_ON(inode->i_state & I_NEW);
+        inode->i_state |= I_FREEING;
+        spin_unlock(&inode->i_lock);
 
-                /* recently referenced inodes get one more pass */
-                if (inode->i_state & I_REFERENCED) {
-                        inode->i_state &= ~I_REFERENCED;
-                        list_move(&inode->i_lru, &sb->s_inode_lru);
-                        spin_unlock(&inode->i_lock);
-                        continue;
-                }
-                if (inode_has_buffers(inode) || inode->i_data.nrpages) {
-                        __iget(inode);
-                        spin_unlock(&inode->i_lock);
-                        spin_unlock(&sb->s_inode_lru_lock);
-                        if (remove_inode_buffers(inode))
-                                reap += invalidate_mapping_pages(&inode->i_data,
-                                                                0, -1);
-                        iput(inode);
-                        spin_lock(&sb->s_inode_lru_lock);
-
-                        if (inode != list_entry(sb->s_inode_lru.next,
-                                                struct inode, i_lru))
-                                continue;       /* wrong inode or list_empty */
-                        /* avoid lock inversions with trylock */
-                        if (!spin_trylock(&inode->i_lock))
-                                continue;
-                        if (!can_unuse(inode)) {
-                                spin_unlock(&inode->i_lock);
-                                continue;
-                        }
-                }
-                WARN_ON(inode->i_state & I_NEW);
-                inode->i_state |= I_FREEING;
-                spin_unlock(&inode->i_lock);
+        list_move(&inode->i_lru, freeable);
+        this_cpu_dec(nr_unused);
+        return LRU_REMOVED;
+}
 
-                list_move(&inode->i_lru, &freeable);
-                sb->s_nr_inodes_unused--;
-                this_cpu_dec(nr_unused);
-                freed++;
-        }
-        if (current_is_kswapd())
-                __count_vm_events(KSWAPD_INODESTEAL, reap);
-        else
-                __count_vm_events(PGINODESTEAL, reap);
-        spin_unlock(&sb->s_inode_lru_lock);
-        if (current->reclaim_state)
-                current->reclaim_state->reclaimed_slab += reap;
+/*
+ * Walk the superblock inode LRU for freeable inodes and attempt to free them.
+ * This is called from the superblock shrinker function with a number of inodes
+ * to trim from the LRU. Inodes to be freed are moved to a temporary list and
+ * then are freed outside inode_lock by dispose_list().
+ */
+long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan)
+{
+        LIST_HEAD(freeable);
+        long freed;
 
+        freed = list_lru_walk(&sb->s_inode_lru, inode_lru_isolate,
+                                                &freeable, nr_to_scan);
         dispose_list(&freeable);
         return freed;
 }