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Subject[PATCH 12/22] UBI: Fastmap: Locking fixes
Date
Add a new rw semaphore to block EBA table changes
while creating the fastmap.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
drivers/mtd/ubi/eba.c | 12 ++++++++++++
drivers/mtd/ubi/fastmap.c | 2 ++
drivers/mtd/ubi/ubi.h | 2 ++
3 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index d112b10..2bee8be 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -340,7 +340,9 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,

dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);

+ down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
+ up_read(&ubi->fm_sem);
err = ubi_wl_put_peb(ubi, pnum, 0);

out_unlock:
@@ -549,7 +551,9 @@ retry:
mutex_unlock(&ubi->buf_mutex);
ubi_free_vid_hdr(ubi, vid_hdr);

+ down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = new_pnum;
+ up_read(&ubi->fm_sem);
ubi_wl_put_peb(ubi, pnum, 1);

ubi_msg("data was successfully recovered");
@@ -667,7 +671,9 @@ retry:
}
}

+ down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = pnum;
+ up_read(&ubi->fm_sem);

leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
@@ -785,7 +791,9 @@ retry:
}

ubi_assert(vol->eba_tbl[lnum] < 0);
+ down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = pnum;
+ up_read(&ubi->fm_sem);

leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
@@ -906,7 +914,9 @@ retry:
goto out_leb_unlock;
}

+ down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = pnum;
+ up_read(&ubi->fm_sem);

out_leb_unlock:
leb_write_unlock(ubi, vol_id, lnum);
@@ -1154,7 +1164,9 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
}

ubi_assert(vol->eba_tbl[lnum] == from);
+ down_read(&ubi->fm_sem);
vol->eba_tbl[lnum] = to;
+ up_read(&ubi->fm_sem);

out_unlock_buf:
mutex_unlock(&ubi->buf_mutex);
diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index ff09fd4..33a14cf 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -1418,9 +1418,11 @@ int ubi_update_fastmap(struct ubi_device *ubi)

kfree(old_fm);

+ down_write(&ubi->fm_sem);
down_write(&ubi->work_sem);
ret = ubi_write_fastmap(ubi, new_fm);
up_write(&ubi->work_sem);
+ up_write(&ubi->fm_sem);
out_unlock:
mutex_unlock(&ubi->fm_mutex);

diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 8588f9c..8abbcd5 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -384,6 +384,7 @@ struct ubi_wl_entry;
* @fm_pool: in-memory data structure of the fastmap pool
* @fm_pool_mutex: serializes ubi_wl_get_peb()
* @fm_mutex: serializes ubi_update_fastmap()
+ * @fm_sem: allows ubi_update_fastmap() to block EBA table changes
* @attached_by_scanning: this UBI device was attached by the old scanning
* methold. All fastmap volumes have to be deleted.
*
@@ -482,6 +483,7 @@ struct ubi_device {
struct ubi_fastmap_layout *fm;
struct ubi_fm_pool fm_pool;
struct ubi_fm_pool fm_wl_pool;
+ struct rw_semaphore fm_sem;
struct mutex fm_mutex;
struct mutex fm_pool_mutex;
int attached_by_scanning;
--
1.7.6.5


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