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UBI: create ltree_entry slab on initialization
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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>
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Artem Bityutskiy authored and Artem Bityutskiy committed Dec 26, 2007
1 parent 01f7b30 commit 3a8d464
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Showing 3 changed files with 67 additions and 67 deletions.
26 changes: 26 additions & 0 deletions drivers/mtd/ubi/build.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand Down Expand Up @@ -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;
Expand All @@ -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];
Expand All @@ -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);
Expand All @@ -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);
}
Expand Down
85 changes: 18 additions & 67 deletions drivers/mtd/ubi/eba.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand All @@ -49,29 +49,6 @@
/* Number of physical eraseblocks reserved for atomic LEB change operation */
#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
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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;
Expand All @@ -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;
}
Expand All @@ -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))
Expand All @@ -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);
Expand All @@ -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);
}

/**
Expand All @@ -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))
Expand All @@ -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);
Expand All @@ -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);
}

/**
Expand Down Expand Up @@ -930,20 +907,6 @@ int ubi_eba_atomic_leb_change(struct ubi_device *ubi, int vol_id, int lnum,
goto retry;
}

/**
* 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
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -1205,8 +1160,6 @@ int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
continue;
kfree(ubi->volumes[i]->eba_tbl);
}
if (ubi_devices_cnt == 0)
kmem_cache_destroy(ltree_slab);
return err;
}

Expand All @@ -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);
}
23 changes: 23 additions & 0 deletions drivers/mtd/ubi/ubi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;

/**
Expand Down Expand Up @@ -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;
Expand Down

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