Commit 111ab0b2 authored by Richard Weinberger's avatar Richard Weinberger
Browse files

UBI: Fastmap: Locking updates 



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: default avatarRichard Weinberger <richard@nod.at>
parent 42dd3cdc

drivers/mtd/ubi/build.c

+2 −2
Original line number Diff line number Diff line
@@ -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", mtd->index);

drivers/mtd/ubi/eba.c

+22 −22
Original line number Diff line number Diff line
@@ -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:
@@ -567,7 +567,7 @@ 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;

	}
@@ -578,14 +578,14 @@ 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;

	}
@@ -597,7 +597,7 @@ 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;

		}

	}
@@ -607,7 +607,7 @@ 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;

	}
@@ -615,7 +615,7 @@ 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");
@@ -710,7 +710,7 @@ 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;

	}
@@ -721,7 +721,7 @@ 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;

	}
@@ -730,13 +730,13 @@ 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);
@@ -833,7 +833,7 @@ 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;

	}
@@ -844,7 +844,7 @@ 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;

	}
@@ -852,13 +852,13 @@ 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);
@@ -953,7 +953,7 @@ 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;

	}
@@ -964,7 +964,7 @@ 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;

	}
@@ -972,13 +972,13 @@ 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);
@@ -1231,9 +1231,9 @@ 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);

drivers/mtd/ubi/fastmap.c

+9 −9
Original line number Diff line number Diff line
@@ -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;

drivers/mtd/ubi/ubi.h

+5 −4
Original line number Diff line number Diff line
@@ -426,10 +426,11 @@ 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

 *
@@ -534,8 +535,8 @@ 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;

drivers/mtd/ubi/wl.c

+12 −7
Original line number Diff line number Diff line
@@ -641,7 +641,7 @@ 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)

{
@@ -650,20 +650,20 @@ 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);

	}
@@ -675,7 +675,7 @@ again: 
			goto out;

		}

		retried = 1;

		up_read(&ubi->fm_sem);

		up_read(&ubi->fm_eba_sem);

		goto again;

	}
@@ -731,7 +731,7 @@ 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;
@@ -1607,6 +1607,8 @@ 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];
@@ -1637,6 +1639,7 @@ 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)) {
@@ -1658,6 +1661,7 @@ 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;

			}

		}
@@ -1671,6 +1675,7 @@ retry: 
		spin_unlock(&ubi->wl_lock);

	}



	up_read(&ubi->fm_protect);

	return err;

}

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