[PATCH 4/6] UBI: Fastmap: Locking updates
Richard Weinberger
richard at nod.at
Sun Nov 30 04:04:28 PST 2014
a) Rename ubi->fm_sem to ubi->fm_eba_sem as this semaphore
protects EBA changes.
b) Turn ubi->fm_mutex into a rw semaphore. It will still serialize
fastmap writes but also ensures that ubi_wl_put_peb() is not
interrupted by a fastmap write. We use a rw semaphore to allow
ubi_wl_put_peb() still to be executed in parallel if no fastmap
write is happening.
Signed-off-by: Richard Weinberger <richard at nod.at>
---
drivers/mtd/ubi/build.c | 4 ++--
drivers/mtd/ubi/eba.c | 44 ++++++++++++++++++++++----------------------
drivers/mtd/ubi/fastmap.c | 18 +++++++++---------
drivers/mtd/ubi/ubi.h | 9 +++++----
drivers/mtd/ubi/wl.c | 19 ++++++++++++-------
5 files changed, 50 insertions(+), 44 deletions(-)
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 32e3d47..3c999e5 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -969,8 +969,8 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num,
mutex_init(&ubi->ckvol_mutex);
mutex_init(&ubi->device_mutex);
spin_lock_init(&ubi->volumes_lock);
- mutex_init(&ubi->fm_mutex);
- init_rwsem(&ubi->fm_sem);
+ init_rwsem(&ubi->fm_protect);
+ init_rwsem(&ubi->fm_eba_sem);
ubi_msg(ubi, "attaching mtd%d to ubi%d", mtd->index, ubi_num);
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index e8e0565..0574b55 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -340,9 +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);
+ down_read(&ubi->fm_eba_sem);
vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 0);
out_unlock:
@@ -510,7 +510,7 @@ retry:
new_pnum = ubi_wl_get_peb(ubi);
if (new_pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
return new_pnum;
}
@@ -521,14 +521,14 @@ retry:
if (err && err != UBI_IO_BITFLIPS) {
if (err > 0)
err = -EIO;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto out_put;
}
vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
if (err) {
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
@@ -540,7 +540,7 @@ retry:
if (offset > 0) {
err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, offset);
if (err && err != UBI_IO_BITFLIPS) {
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto out_unlock;
}
}
@@ -550,7 +550,7 @@ retry:
err = ubi_io_write_data(ubi, ubi->peb_buf, new_pnum, 0, data_size);
if (err) {
mutex_unlock(&ubi->buf_mutex);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
@@ -558,7 +558,7 @@ retry:
ubi_free_vid_hdr(ubi, vid_hdr);
vol->eba_tbl[lnum] = new_pnum;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
ubi_msg(ubi, "data was successfully recovered");
@@ -653,7 +653,7 @@ retry:
if (pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
leb_write_unlock(ubi, vol_id, lnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
return pnum;
}
@@ -664,7 +664,7 @@ retry:
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
@@ -673,13 +673,13 @@ retry:
if (err) {
ubi_warn(ubi, "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
}
vol->eba_tbl[lnum] = pnum;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
@@ -776,7 +776,7 @@ retry:
if (pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
leb_write_unlock(ubi, vol_id, lnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
return pnum;
}
@@ -787,7 +787,7 @@ retry:
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
@@ -795,13 +795,13 @@ retry:
if (err) {
ubi_warn(ubi, "failed to write %d bytes of data to PEB %d",
len, pnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
ubi_assert(vol->eba_tbl[lnum] < 0);
vol->eba_tbl[lnum] = pnum;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
@@ -896,7 +896,7 @@ retry:
pnum = ubi_wl_get_peb(ubi);
if (pnum < 0) {
err = pnum;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto out_leb_unlock;
}
@@ -907,7 +907,7 @@ retry:
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
@@ -915,13 +915,13 @@ retry:
if (err) {
ubi_warn(ubi, "failed to write %d bytes of data to PEB %d",
len, pnum);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto write_error;
}
old_pnum = vol->eba_tbl[lnum];
vol->eba_tbl[lnum] = pnum;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
if (old_pnum >= 0) {
err = ubi_wl_put_peb(ubi, vol_id, lnum, old_pnum, 0);
@@ -1174,9 +1174,9 @@ 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);
+ down_read(&ubi->fm_eba_sem);
vol->eba_tbl[lnum] = to;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
out_unlock_buf:
mutex_unlock(&ubi->buf_mutex);
diff --git a/drivers/mtd/ubi/fastmap.c b/drivers/mtd/ubi/fastmap.c
index 749e2e4..2cf2506 100644
--- a/drivers/mtd/ubi/fastmap.c
+++ b/drivers/mtd/ubi/fastmap.c
@@ -800,7 +800,7 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
__be32 crc, tmp_crc;
unsigned long long sqnum = 0;
- mutex_lock(&ubi->fm_mutex);
+ down_write(&ubi->fm_protect);
memset(ubi->fm_buf, 0, ubi->fm_size);
fmsb = kmalloc(sizeof(*fmsb), GFP_KERNEL);
@@ -991,7 +991,7 @@ int ubi_scan_fastmap(struct ubi_device *ubi, struct ubi_attach_info *ai,
ubi_free_vid_hdr(ubi, vh);
kfree(ech);
out:
- mutex_unlock(&ubi->fm_mutex);
+ up_write(&ubi->fm_protect);
if (ret == UBI_BAD_FASTMAP)
ubi_err(ubi, "Attach by fastmap failed, doing a full scan!");
return ret;
@@ -1340,24 +1340,24 @@ int ubi_update_fastmap(struct ubi_device *ubi)
struct ubi_fastmap_layout *new_fm, *old_fm;
struct ubi_wl_entry *tmp_e;
- mutex_lock(&ubi->fm_mutex);
+ down_write(&ubi->fm_protect);
ubi_refill_pools(ubi);
if (ubi->ro_mode || ubi->fm_disabled) {
- mutex_unlock(&ubi->fm_mutex);
+ up_write(&ubi->fm_protect);
return 0;
}
ret = ubi_ensure_anchor_pebs(ubi);
if (ret) {
- mutex_unlock(&ubi->fm_mutex);
+ up_write(&ubi->fm_protect);
return ret;
}
new_fm = kzalloc(sizeof(*new_fm), GFP_KERNEL);
if (!new_fm) {
- mutex_unlock(&ubi->fm_mutex);
+ up_write(&ubi->fm_protect);
return -ENOMEM;
}
@@ -1447,16 +1447,16 @@ int ubi_update_fastmap(struct ubi_device *ubi)
}
down_write(&ubi->work_sem);
- down_write(&ubi->fm_sem);
+ down_write(&ubi->fm_eba_sem);
ret = ubi_write_fastmap(ubi, new_fm);
- up_write(&ubi->fm_sem);
+ up_write(&ubi->fm_eba_sem);
up_write(&ubi->work_sem);
if (ret)
goto err;
out_unlock:
- mutex_unlock(&ubi->fm_mutex);
+ up_write(&ubi->fm_protect);
kfree(old_fm);
return ret;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 6fadf34..233e742 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -422,10 +422,11 @@ struct ubi_debug_info {
* @fm_pool: in-memory data structure of the fastmap pool
* @fm_wl_pool: in-memory data structure of the fastmap pool used by the WL
* sub-system
- * @fm_mutex: serializes ubi_update_fastmap() and protects @fm_buf
+ * @fm_protect: serializes ubi_update_fastmap(), protects @fm_buf and makes sure
+ * that critical sections cannot be interrupted by ubi_update_fastmap()
* @fm_buf: vmalloc()'d buffer which holds the raw fastmap
* @fm_size: fastmap size in bytes
- * @fm_sem: allows ubi_update_fastmap() to block EBA table changes
+ * @fm_eba_sem: allows ubi_update_fastmap() to block EBA table changes
* @fm_work: fastmap work queue
* @fm_work_scheduled: non-zero if fastmap work was scheduled
*
@@ -530,8 +531,8 @@ 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 rw_semaphore fm_eba_sem;
+ struct rw_semaphore fm_protect;
void *fm_buf;
size_t fm_size;
struct work_struct fm_work;
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index f2ca6a0..4565419 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -644,7 +644,7 @@ void ubi_refill_pools(struct ubi_device *ubi)
/* ubi_wl_get_peb - works exaclty like __wl_get_peb but keeps track of
* the fastmap pool.
- * Returns with ubi->fm_sem held in read mode!
+ * Returns with ubi->fm_eba_sem held in read mode!
*/
int ubi_wl_get_peb(struct ubi_device *ubi)
{
@@ -653,20 +653,20 @@ int ubi_wl_get_peb(struct ubi_device *ubi)
struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
again:
- down_read(&ubi->fm_sem);
+ down_read(&ubi->fm_eba_sem);
spin_lock(&ubi->wl_lock);
/* We check here also for the WL pool because at this point we can
* refill the WL pool synchronous. */
if (pool->used == pool->size || wl_pool->used == wl_pool->size) {
spin_unlock(&ubi->wl_lock);
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
ret = ubi_update_fastmap(ubi);
if (ret) {
ubi_msg(ubi, "Unable to write a new fastmap: %i", ret);
- down_read(&ubi->fm_sem);
+ down_read(&ubi->fm_eba_sem);
return -ENOSPC;
}
- down_read(&ubi->fm_sem);
+ down_read(&ubi->fm_eba_sem);
spin_lock(&ubi->wl_lock);
}
@@ -678,7 +678,7 @@ again:
goto out;
}
retried = 1;
- up_read(&ubi->fm_sem);
+ up_read(&ubi->fm_eba_sem);
goto again;
}
@@ -734,7 +734,7 @@ int ubi_wl_get_peb(struct ubi_device *ubi)
spin_lock(&ubi->wl_lock);
peb = wl_get_peb(ubi);
spin_unlock(&ubi->wl_lock);
- down_read(&ubi->fm_sem);
+ down_read(&ubi->fm_eba_sem);
if (peb < 0)
return peb;
@@ -1610,6 +1610,8 @@ int ubi_wl_put_peb(struct ubi_device *ubi, int vol_id, int lnum,
ubi_assert(pnum >= 0);
ubi_assert(pnum < ubi->peb_count);
+ down_read(&ubi->fm_protect);
+
retry:
spin_lock(&ubi->wl_lock);
e = ubi->lookuptbl[pnum];
@@ -1640,6 +1642,7 @@ retry:
ubi_assert(!ubi->move_to_put);
ubi->move_to_put = 1;
spin_unlock(&ubi->wl_lock);
+ up_read(&ubi->fm_protect);
return 0;
} else {
if (in_wl_tree(e, &ubi->used)) {
@@ -1661,6 +1664,7 @@ retry:
ubi_err(ubi, "PEB %d not found", pnum);
ubi_ro_mode(ubi);
spin_unlock(&ubi->wl_lock);
+ up_read(&ubi->fm_protect);
return err;
}
}
@@ -1674,6 +1678,7 @@ retry:
spin_unlock(&ubi->wl_lock);
}
+ up_read(&ubi->fm_protect);
return err;
}
--
1.8.4.5
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