1 files changed, 43 insertions, 101 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index f514dd392cd9..e6d9298aa22a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1079,104 +1079,47 @@ redirty:
 
 #ifdef CONFIG_NUMA
 #ifdef CONFIG_TMPFS
-static int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
+static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
 {
-        char *nodelist = strchr(value, ':');
-        int err = 1;
+        char buffer[64];
 
-        if (nodelist) {
-                /* NUL-terminate policy string */
-                *nodelist++ = '\0';
-                if (nodelist_parse(nodelist, *policy_nodes))
-                        goto out;
-                if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY]))
-                        goto out;
-        }
-        if (!strcmp(value, "default")) {
-                *policy = MPOL_DEFAULT;
-                /* Don't allow a nodelist */
-                if (!nodelist)
-                        err = 0;
-        } else if (!strcmp(value, "prefer")) {
-                *policy = MPOL_PREFERRED;
-                /* Insist on a nodelist of one node only */
-                if (nodelist) {
-                        char *rest = nodelist;
-                        while (isdigit(*rest))
-                                rest++;
-                        if (!*rest)
-                                err = 0;
-                }
-        } else if (!strcmp(value, "bind")) {
-                *policy = MPOL_BIND;
-                /* Insist on a nodelist */
-                if (nodelist)
-                        err = 0;
-        } else if (!strcmp(value, "interleave")) {
-                *policy = MPOL_INTERLEAVE;
-                /*
-                 * Default to online nodes with memory if no nodelist
-                 */
-                if (!nodelist)
-                        *policy_nodes = node_states[N_HIGH_MEMORY];
-                err = 0;
-        }
-out:
-        /* Restore string for error message */
-        if (nodelist)
-                *--nodelist = ':';
-        return err;
-}
-
-static void shmem_show_mpol(struct seq_file *seq, int policy,
-                            const nodemask_t policy_nodes)
-{
-        char *policy_string;
+        if (!mpol || mpol->mode == MPOL_DEFAULT)
+                return;         /* show nothing */
 
-        switch (policy) {
-        case MPOL_PREFERRED:
-                policy_string = "prefer";
-                break;
-        case MPOL_BIND:
-                policy_string = "bind";
-                break;
-        case MPOL_INTERLEAVE:
-                policy_string = "interleave";
-                break;
-        default:
-                /* MPOL_DEFAULT */
-                return;
-        }
+        mpol_to_str(buffer, sizeof(buffer), mpol, 1);
 
-        seq_printf(seq, ",mpol=%s", policy_string);
-
-        if (policy != MPOL_INTERLEAVE ||
-            !nodes_equal(policy_nodes, node_states[N_HIGH_MEMORY])) {
-                char buffer[64];
-                int len;
+        seq_printf(seq, ",mpol=%s", buffer);
+}
 
-                len = nodelist_scnprintf(buffer, sizeof(buffer), policy_nodes);
-                if (len < sizeof(buffer))
-                        seq_printf(seq, ":%s", buffer);
-                else
-                        seq_printf(seq, ":?");
+static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
+{
+        struct mempolicy *mpol = NULL;
+        if (sbinfo->mpol) {
+                spin_lock(&sbinfo->stat_lock);  /* prevent replace/use races */
+                mpol = sbinfo->mpol;
+                mpol_get(mpol);
+                spin_unlock(&sbinfo->stat_lock);
         }
+        return mpol;
 }
 #endif /* CONFIG_TMPFS */
 
 static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
                         struct shmem_inode_info *info, unsigned long idx)
 {
+        struct mempolicy mpol, *spol;
         struct vm_area_struct pvma;
         struct page *page;
 
+        spol = mpol_cond_copy(&mpol,
+                                mpol_shared_policy_lookup(&info->policy, idx));
+
         /* Create a pseudo vma that just contains the policy */
         pvma.vm_start = 0;
         pvma.vm_pgoff = idx;
         pvma.vm_ops = NULL;
-        pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
+        pvma.vm_policy = spol;
         page = swapin_readahead(entry, gfp, &pvma, 0);
-        mpol_free(pvma.vm_policy);
         return page;
 }
 
@@ -1184,27 +1127,21 @@ static struct page *shmem_alloc_page(gfp_t gfp,
                         struct shmem_inode_info *info, unsigned long idx)
 {
         struct vm_area_struct pvma;
-        struct page *page;
 
         /* Create a pseudo vma that just contains the policy */
         pvma.vm_start = 0;
         pvma.vm_pgoff = idx;
         pvma.vm_ops = NULL;
         pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
-        page = alloc_page_vma(gfp, &pvma, 0);
-        mpol_free(pvma.vm_policy);
-        return page;
+
+        /*
+         * alloc_page_vma() will drop the shared policy reference
+         */
+        return alloc_page_vma(gfp, &pvma, 0);
 }
 #else /* !CONFIG_NUMA */
 #ifdef CONFIG_TMPFS
-static inline int shmem_parse_mpol(char *value, int *policy,
-                                                nodemask_t *policy_nodes)
-{
-        return 1;
-}
-
-static inline void shmem_show_mpol(struct seq_file *seq, int policy,
-                            const nodemask_t policy_nodes)
+static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p)
 {
 }
 #endif /* CONFIG_TMPFS */
@@ -1222,6 +1159,13 @@ static inline struct page *shmem_alloc_page(gfp_t gfp,
 }
 #endif /* CONFIG_NUMA */
 
+#if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
+static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
+{
+        return NULL;
+}
+#endif
+
 /*
  * shmem_getpage - either get the page from swap or allocate a new one
  *
@@ -1576,8 +1520,8 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
                 case S_IFREG:
                         inode->i_op = &shmem_inode_operations;
                         inode->i_fop = &shmem_file_operations;
-                        mpol_shared_policy_init(&info->policy, sbinfo->policy,
-                                                        &sbinfo->policy_nodes);
+                        mpol_shared_policy_init(&info->policy,
+                                                 shmem_get_sbmpol(sbinfo));
                         break;
                 case S_IFDIR:
                         inc_nlink(inode);
@@ -1591,8 +1535,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
                          * Must not load anything in the rbtree,
                          * mpol_free_shared_policy will not be called.
                          */
-                        mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
-                                                NULL);
+                        mpol_shared_policy_init(&info->policy, NULL);
                         break;
                 }
         } else
@@ -2207,8 +2150,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
                         if (*rest)
                                 goto bad_val;
                 } else if (!strcmp(this_char,"mpol")) {
-                        if (shmem_parse_mpol(value, &sbinfo->policy,
-                                             &sbinfo->policy_nodes))
+                        if (mpol_parse_str(value, &sbinfo->mpol, 1))
                                 goto bad_val;
                 } else {
                         printk(KERN_ERR "tmpfs: Bad mount option %s\n",
@@ -2259,8 +2201,9 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
         sbinfo->free_blocks = config.max_blocks - blocks;
         sbinfo->max_inodes  = config.max_inodes;
         sbinfo->free_inodes = config.max_inodes - inodes;
-        sbinfo->policy      = config.policy;
-        sbinfo->policy_nodes = config.policy_nodes;
+
+        mpol_put(sbinfo->mpol);
+        sbinfo->mpol        = config.mpol;      /* transfers initial ref */
 out:
         spin_unlock(&sbinfo->stat_lock);
         return error;
@@ -2281,7 +2224,7 @@ static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_printf(seq, ",uid=%u", sbinfo->uid);
         if (sbinfo->gid != 0)
                 seq_printf(seq, ",gid=%u", sbinfo->gid);
-        shmem_show_mpol(seq, sbinfo->policy, sbinfo->policy_nodes);
+        shmem_show_mpol(seq, sbinfo->mpol);
         return 0;
 }
 #endif /* CONFIG_TMPFS */
@@ -2311,8 +2254,7 @@ static int shmem_fill_super(struct super_block *sb,
         sbinfo->mode = S_IRWXUGO | S_ISVTX;
         sbinfo->uid = current->fsuid;
         sbinfo->gid = current->fsgid;
-        sbinfo->policy = MPOL_DEFAULT;
-        sbinfo->policy_nodes = node_states[N_HIGH_MEMORY];
+        sbinfo->mpol = NULL;
         sb->s_fs_info = sbinfo;
 
 #ifdef CONFIG_TMPFS