UBI: create ltree_entry slab on initialization

Since the ltree_entry slab cache is a global entity, which is
used by all UBI devices, it is more logical to create it on
module initialization time and destro on module exit time.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

3 files changed, 67 insertions, 67 deletions

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 5490a73deca5..44c852144a9c 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -67,6 +67,9 @@ struct ubi_device *ubi_devices[UBI_MAX_DEVICES];
 /* Root UBI "class" object (corresponds to '/<sysfs>/class/ubi/') */
 struct class *ubi_class;
 
+/* Slab cache for lock-tree entries */
+struct kmem_cache *ubi_ltree_slab;
+
 /* "Show" method for files in '/<sysfs>/class/ubi/' */
 static ssize_t ubi_version_show(struct class *class, char *buf)
 {
@@ -687,6 +690,20 @@ static void detach_mtd_dev(struct ubi_device *ubi)
         ubi_msg("mtd%d is detached from ubi%d", mtd_num, ubi_num);
 }
 
+/**
+ * ltree_entry_ctor - lock tree entries slab cache constructor.
+ * @obj: the lock-tree entry to construct
+ * @cache: the lock tree entry slab cache
+ * @flags: constructor flags
+ */
+static void ltree_entry_ctor(struct kmem_cache *cache, void *obj)
+{
+        struct ubi_ltree_entry *le = obj;
+
+        le->users = 0;
+        init_rwsem(&le->mutex);
+}
+
 static int __init ubi_init(void)
 {
         int err, i, k;
@@ -709,6 +726,12 @@ static int __init ubi_init(void)
         if (err)
                 goto out_class;
 
+        ubi_ltree_slab = kmem_cache_create("ubi_ltree_slab",
+                                           sizeof(struct ubi_ltree_entry), 0,
+                                           0, &ltree_entry_ctor);
+        if (!ubi_ltree_slab)
+                goto out_version;
+
         /* Attach MTD devices */
         for (i = 0; i < mtd_devs; i++) {
                 struct mtd_dev_param *p = &mtd_dev_param[i];
@@ -724,6 +747,8 @@ static int __init ubi_init(void)
 out_detach:
         for (k = 0; k < i; k++)
                 detach_mtd_dev(ubi_devices[k]);
+        kmem_cache_destroy(ubi_ltree_slab);
+out_version:
         class_remove_file(ubi_class, &ubi_version);
 out_class:
         class_destroy(ubi_class);
@@ -737,6 +762,7 @@ static void __exit ubi_exit(void)
 
         for (i = 0; i < n; i++)
                 detach_mtd_dev(ubi_devices[i]);
+        kmem_cache_destroy(ubi_ltree_slab);
         class_remove_file(ubi_class, &ubi_version);
         class_destroy(ubi_class);
 }
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index c87db07bcd0c..5fdb31bc5636 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -31,7 +31,7 @@
  * logical eraseblock it is locked for reading or writing. The per-logical
  * eraseblock locking is implemented by means of the lock tree. The lock tree
  * is an RB-tree which refers all the currently locked logical eraseblocks. The
- * lock tree elements are &struct ltree_entry objects. They are indexed by
+ * lock tree elements are &struct ubi_ltree_entry objects. They are indexed by
  * (@vol_id, @lnum) pairs.
  *
  * EBA also maintains the global sequence counter which is incremented each
@@ -50,29 +50,6 @@
 #define EBA_RESERVED_PEBS 1
 
 /**
- * struct ltree_entry - an entry in the lock tree.
- * @rb: links RB-tree nodes
- * @vol_id: volume ID of the locked logical eraseblock
- * @lnum: locked logical eraseblock number
- * @users: how many tasks are using this logical eraseblock or wait for it
- * @mutex: read/write mutex to implement read/write access serialization to
- * the (@vol_id, @lnum) logical eraseblock
- *
- * When a logical eraseblock is being locked - corresponding &struct ltree_entry
- * object is inserted to the lock tree (@ubi->ltree).
- */
-struct ltree_entry {
-        struct rb_node rb;
-        int vol_id;
-        int lnum;
-        int users;
-        struct rw_semaphore mutex;
-};
-
-/* Slab cache for lock-tree entries */
-static struct kmem_cache *ltree_slab;
-
-/**
  * next_sqnum - get next sequence number.
  * @ubi: UBI device description object
  *
@@ -112,20 +89,20 @@ static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
  * @vol_id: volume ID
  * @lnum: logical eraseblock number
  *
- * This function returns a pointer to the corresponding &struct ltree_entry
+ * This function returns a pointer to the corresponding &struct ubi_ltree_entry
  * object if the logical eraseblock is locked and %NULL if it is not.
  * @ubi->ltree_lock has to be locked.
  */
-static struct ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
-                                        int lnum)
+static struct ubi_ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
+                                            int lnum)
 {
         struct rb_node *p;
 
         p = ubi->ltree.rb_node;
         while (p) {
-                struct ltree_entry *le;
+                struct ubi_ltree_entry *le;
 
-                le = rb_entry(p, struct ltree_entry, rb);
+                le = rb_entry(p, struct ubi_ltree_entry, rb);
 
                 if (vol_id < le->vol_id)
                         p = p->rb_left;
@@ -155,12 +132,12 @@ static struct ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
  * Returns pointer to the lock tree entry or %-ENOMEM if memory allocation
  * failed.
  */
-static struct ltree_entry *ltree_add_entry(struct ubi_device *ubi, int vol_id,
-                                           int lnum)
+static struct ubi_ltree_entry *ltree_add_entry(struct ubi_device *ubi,
+                                               int vol_id, int lnum)
 {
-        struct ltree_entry *le, *le1, *le_free;
+        struct ubi_ltree_entry *le, *le1, *le_free;
 
-        le = kmem_cache_alloc(ltree_slab, GFP_NOFS);
+        le = kmem_cache_alloc(ubi_ltree_slab, GFP_NOFS);
         if (!le)
                 return ERR_PTR(-ENOMEM);
 
@@ -189,7 +166,7 @@ static struct ltree_entry *ltree_add_entry(struct ubi_device *ubi, int vol_id,
                 p = &ubi->ltree.rb_node;
                 while (*p) {
                         parent = *p;
-                        le1 = rb_entry(parent, struct ltree_entry, rb);
+                        le1 = rb_entry(parent, struct ubi_ltree_entry, rb);
 
                         if (vol_id < le1->vol_id)
                                 p = &(*p)->rb_left;
@@ -211,7 +188,7 @@ static struct ltree_entry *ltree_add_entry(struct ubi_device *ubi, int vol_id,
         spin_unlock(&ubi->ltree_lock);
 
         if (le_free)
-                kmem_cache_free(ltree_slab, le_free);
+                kmem_cache_free(ubi_ltree_slab, le_free);
 
         return le;
 }
@@ -227,7 +204,7 @@ static struct ltree_entry *ltree_add_entry(struct ubi_device *ubi, int vol_id,
  */
 static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
 {
-        struct ltree_entry *le;
+        struct ubi_ltree_entry *le;
 
         le = ltree_add_entry(ubi, vol_id, lnum);
         if (IS_ERR(le))
@@ -245,7 +222,7 @@ static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
 static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 {
         int free = 0;
-        struct ltree_entry *le;
+        struct ubi_ltree_entry *le;
 
         spin_lock(&ubi->ltree_lock);
         le = ltree_lookup(ubi, vol_id, lnum);
@@ -259,7 +236,7 @@ static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 
         up_read(&le->mutex);
         if (free)
-                kmem_cache_free(ltree_slab, le);
+                kmem_cache_free(ubi_ltree_slab, le);
 }
 
 /**
@@ -273,7 +250,7 @@ static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
  */
 static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
 {
-        struct ltree_entry *le;
+        struct ubi_ltree_entry *le;
 
         le = ltree_add_entry(ubi, vol_id, lnum);
         if (IS_ERR(le))
@@ -291,7 +268,7 @@ static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
 static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 {
         int free;
-        struct ltree_entry *le;
+        struct ubi_ltree_entry *le;
 
         spin_lock(&ubi->ltree_lock);
         le = ltree_lookup(ubi, vol_id, lnum);
@@ -306,7 +283,7 @@ static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
 
         up_write(&le->mutex);
         if (free)
-                kmem_cache_free(ltree_slab, le);
+                kmem_cache_free(ubi_ltree_slab, le);
 }
 
 /**
@@ -931,20 +908,6 @@ write_error:
 }
 
 /**
- * ltree_entry_ctor - lock tree entries slab cache constructor.
- * @obj: the lock-tree entry to construct
- * @cache: the lock tree entry slab cache
- * @flags: constructor flags
- */
-static void ltree_entry_ctor(struct kmem_cache *cache, void *obj)
-{
-        struct ltree_entry *le = obj;
-
-        le->users = 0;
-        init_rwsem(&le->mutex);
-}
-
-/**
  * ubi_eba_copy_leb - copy logical eraseblock.
  * @ubi: UBI device description object
  * @from: physical eraseblock number from where to copy
@@ -1128,14 +1091,6 @@ int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
         mutex_init(&ubi->alc_mutex);
         ubi->ltree = RB_ROOT;
 
-        if (ubi_devices_cnt == 0) {
-                ltree_slab = kmem_cache_create("ubi_ltree_slab",
-                                               sizeof(struct ltree_entry), 0,
-                                               0, &ltree_entry_ctor);
-                if (!ltree_slab)
-                        return -ENOMEM;
-        }
-
         ubi->global_sqnum = si->max_sqnum + 1;
         num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
 
@@ -1205,8 +1160,6 @@ out_free:
                         continue;
                 kfree(ubi->volumes[i]->eba_tbl);
         }
-        if (ubi_devices_cnt == 0)
-                kmem_cache_destroy(ltree_slab);
         return err;
 }
 
@@ -1225,6 +1178,4 @@ void ubi_eba_close(const struct ubi_device *ubi)
                         continue;
                 kfree(ubi->volumes[i]->eba_tbl);
         }
-        if (ubi_devices_cnt == 1)
-                kmem_cache_destroy(ltree_slab);
 }
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 318ce2543fb8..0f2ea81b3122 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -97,6 +97,28 @@ enum {
 extern int ubi_devices_cnt;
 extern struct ubi_device *ubi_devices[];
 
+/**
+ * struct ubi_ltree_entry - an entry in the lock tree.
+ * @rb: links RB-tree nodes
+ * @vol_id: volume ID of the locked logical eraseblock
+ * @lnum: locked logical eraseblock number
+ * @users: how many tasks are using this logical eraseblock or wait for it
+ * @mutex: read/write mutex to implement read/write access serialization to
+ *         the (@vol_id, @lnum) logical eraseblock
+ *
+ * This data structure is used in the EBA unit to implement per-LEB locking.
+ * When a logical eraseblock is being locked - corresponding
+ * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
+ * See EBA unit for details.
+ */
+struct ubi_ltree_entry {
+        struct rb_node rb;
+        int vol_id;
+        int lnum;
+        int users;
+        struct rw_semaphore mutex;
+};
+
 struct ubi_volume_desc;
 
 /**
@@ -359,6 +381,7 @@ struct ubi_device {
 #endif
 };
 
+extern struct kmem_cache *ubi_ltree_slab;
 extern struct file_operations ubi_cdev_operations;
 extern struct file_operations ubi_vol_cdev_operations;
 extern struct class *ubi_class;