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Subject[PATCH 04/15] UBI: Fastmap: Always refill pools upon writing a new fastmap.
Date
If we allow writing a new fastmap without refilling the current
pool at attach time we have to think about strange corner cases.
E.g. A PEB can be within a pool and in the free or used list.
To simplify the code for attaching this change has been made.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
drivers/mtd/ubi/fastmap.c | 14 +++++-
drivers/mtd/ubi/ubi.h | 1 +
drivers/mtd/ubi/wl.c | 100 ++++++++++++++++++++++++++-------------------
3 files changed, 70 insertions(+), 45 deletions(-)

diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index cccb0c9..ba69267 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -1362,12 +1362,20 @@ int ubi_update_fastmap(struct ubi_device *ubi)
struct ubi_fastmap_layout *new_fm, *old_fm;
struct ubi_wl_entry *tmp_e;

- if (ubi->ro_mode)
+ mutex_lock(&ubi->fm_mutex);
+
+ ubi_refill_pools(ubi);
+
+ if (ubi->ro_mode) {
+ mutex_unlock(&ubi->fm_mutex);
return 0;
+ }

new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
- if (!new_fm)
+ if (!new_fm) {
+ mutex_unlock(&ubi->fm_mutex);
return -ENOMEM;
+ }

new_fm->size = sizeof(struct ubi_fm_hdr) + \
sizeof(struct ubi_fm_scan_pool) + \
@@ -1387,11 +1395,11 @@ int ubi_update_fastmap(struct ubi_device *ubi)
kfree(new_fm->e[i]);

kfree(new_fm);
+ mutex_unlock(&ubi->fm_mutex);
return -ENOMEM;
}
}

- mutex_lock(&ubi->fm_mutex);
old_fm = ubi->fm;
ubi->fm = NULL;

diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index a568a3b..a0c2103 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -757,6 +757,7 @@ int ubi_thread(void *u);
struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int max_pnum);
int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *used_e, int torture);
int ubi_is_erase_work(struct ubi_work *wrk);
+void ubi_refill_pools(struct ubi_device *ubi);

/* io.c */
int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index f4d2c79..ec0a954 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -497,43 +497,76 @@ retry:

return e->pnum;
}
-
-static int refill_wl_pool(struct ubi_device *ubi)
+/**
+ * return_unused_pool_pebs - returns unused PEB to the free tree.
+ * @ubi: UBI device description object
+ * @pool: fastmap pool description object
+ */
+static void return_unused_pool_pebs(struct ubi_device *ubi,
+ struct ubi_fm_pool *pool)
{
- int ret, i;
- struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+ int i;
struct ubi_wl_entry *e;

- spin_lock(&ubi->wl_lock);
- if (pool->used != pool->size && pool->size) {
- spin_unlock(&ubi->wl_lock);
- return 0;
+ for (i = pool->used; i < pool->size; i++) {
+ e = ubi->lookuptbl[pool->pebs[i]];
+ wl_tree_add(e, &ubi->free);
}
+}

- for (i = 0; i < pool->max_size; i++) {
- if (!ubi->free.rb_node) {
- spin_unlock(&ubi->wl_lock);
+/**
+ * refill_wl_pool - refills all the fastmap pool used by the
+ * WL sub-system.
+ * @ubi: UBI device description object
+ */
+static void refill_wl_pool(struct ubi_device *ubi)
+{
+ struct ubi_wl_entry *e;
+ struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+
+ return_unused_pool_pebs(ubi, pool);
+
+ for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
+ if (!ubi->free.rb_node)
break;
- }

e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
self_check_in_wl_tree(ubi, e, &ubi->free);
rb_erase(&e->u.rb, &ubi->free);

- pool->pebs[i] = e->pnum;
+ pool->pebs[pool->size] = e->pnum;
}
- pool->size = i;
- spin_unlock(&ubi->wl_lock);
+ pool->used = 0;
+}
+
+/**
+ * refill_wl_user_pool - refills all the fastmap pool used by ubi_wl_get_peb.
+ * @ubi: UBI device description object
+ */
+static void refill_wl_user_pool(struct ubi_device *ubi)
+{
+ struct ubi_fm_pool *pool = &ubi->fm_pool;

- ret = ubi_update_fastmap(ubi);
- if (ret) {
- ubi_ro_mode(ubi);
+ return_unused_pool_pebs(ubi, pool);

- return ret > 0 ? -EINVAL : ret;
+ for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
+ pool->pebs[pool->size] = __ubi_wl_get_peb(ubi);
+ if (pool->pebs[pool->size] < 0)
+ break;
}
pool->used = 0;
+}

- return pool->size ? 0 : -ENOSPC;
+/**
+ * ubi_refill_pools - refills all fastmap PEB pools.
+ * @ubi: UBI device description object
+ */
+void ubi_refill_pools(struct ubi_device *ubi)
+{
+ spin_lock(&ubi->wl_lock);
+ refill_wl_pool(ubi);
+ refill_wl_user_pool(ubi);
+ spin_unlock(&ubi->wl_lock);
}

/* ubi_wl_get_peb - works exaclty like __ubi_wl_get_peb but keeps track of
@@ -541,32 +574,15 @@ static int refill_wl_pool(struct ubi_device *ubi)
*/
int ubi_wl_get_peb(struct ubi_device *ubi)
{
- struct ubi_fm_pool *pool = &ubi->fm_pool;
int ret;
+ struct ubi_fm_pool *pool = &ubi->fm_pool;
+ struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;

mutex_lock(&ubi->fm_pool_mutex);

- refill_wl_pool(ubi);
-
- /* pool contains no free blocks, create a new one
- * and write a fastmap */
- if (pool->used == pool->size || !pool->size) {
- for (pool->size = 0; pool->size < pool->max_size;
- pool->size++) {
- pool->pebs[pool->size] = __ubi_wl_get_peb(ubi);
- if (pool->pebs[pool->size] < 0)
- break;
- }
-
- pool->used = 0;
- ret = ubi_update_fastmap(ubi);
- if (ret) {
- ubi_ro_mode(ubi);
- mutex_unlock(&ubi->fm_pool_mutex);
-
- return ret > 0 ? -EINVAL : ret;
- }
- }
+ if (!pool->size || !wl_pool->size || pool->used == pool->size ||
+ wl_pool->used == wl_pool->size)
+ ubi_update_fastmap(ubi);

/* we got not a single free PEB */
if (!pool->size)
--
1.7.6.5


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