mtd: ubi: wl: avoid erasing a PEB which is empty

[linux-drm-fsl-dcu.git] / drivers / mtd / ubi / wl.c

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index eb4489f9082fe84345d2ec68b0f8723888e5c177..17ec948ac40e5c63fd8f16608ee503bc7aeee5f0 100644 (file)
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -603,6 +603,7 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
        return 0;
 }
 
+static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk);
 /**
  * do_sync_erase - run the erase worker synchronously.
  * @ubi: UBI device description object
@@ -615,22 +616,19 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
 static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
                         int vol_id, int lnum, int torture)
 {
-       struct ubi_work *wl_wrk;
+       struct ubi_work wl_wrk;
 
        dbg_wl("sync erase of PEB %i", e->pnum);
 
-       wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
-       if (!wl_wrk)
-               return -ENOMEM;
+       wl_wrk.e = e;
+       wl_wrk.vol_id = vol_id;
+       wl_wrk.lnum = lnum;
+       wl_wrk.torture = torture;
 
-       wl_wrk->e = e;
-       wl_wrk->vol_id = vol_id;
-       wl_wrk->lnum = lnum;
-       wl_wrk->torture = torture;
-
-       return erase_worker(ubi, wl_wrk, 0);
+       return __erase_worker(ubi, &wl_wrk);
 }
 
+static int ensure_wear_leveling(struct ubi_device *ubi, int nested);
 /**
  * wear_leveling_worker - wear-leveling worker function.
  * @ubi: UBI device description object
@@ -652,6 +650,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 #endif
        struct ubi_wl_entry *e1, *e2;
        struct ubi_vid_hdr *vid_hdr;
+       int dst_leb_clean = 0;
 
        kfree(wrk);
        if (shutdown)
@@ -756,6 +755,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
 
        err = ubi_io_read_vid_hdr(ubi, e1->pnum, vid_hdr, 0);
        if (err && err != UBI_IO_BITFLIPS) {
+               dst_leb_clean = 1;
                if (err == UBI_IO_FF) {
                        /*
                         * We are trying to move PEB without a VID header. UBI
@@ -801,10 +801,12 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                         * protection queue.
                         */
                        protect = 1;
+                       dst_leb_clean = 1;
                        goto out_not_moved;
                }
                if (err == MOVE_RETRY) {
                        scrubbing = 1;
+                       dst_leb_clean = 1;
                        goto out_not_moved;
                }
                if (err == MOVE_TARGET_BITFLIPS || err == MOVE_TARGET_WR_ERR ||
@@ -830,6 +832,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
                                        ubi->erroneous_peb_count);
                                goto out_error;
                        }
+                       dst_leb_clean = 1;
                        erroneous = 1;
                        goto out_not_moved;
                }
@@ -900,15 +903,24 @@ out_not_moved:
                wl_tree_add(e1, &ubi->scrub);
        else
                wl_tree_add(e1, &ubi->used);
+       if (dst_leb_clean) {
+               wl_tree_add(e2, &ubi->free);
+               ubi->free_count++;
+       }
+
        ubi_assert(!ubi->move_to_put);
        ubi->move_from = ubi->move_to = NULL;
        ubi->wl_scheduled = 0;
        spin_unlock(&ubi->wl_lock);
 
        ubi_free_vid_hdr(ubi, vid_hdr);
-       err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
-       if (err)
-               goto out_ro;
+       if (dst_leb_clean) {
+               ensure_wear_leveling(ubi, 1);
+       } else {
+               err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
+               if (err)
+                       goto out_ro;
+       }
 
        mutex_unlock(&ubi->move_mutex);
        return 0;
@@ -1014,7 +1026,7 @@ out_unlock:
 }
 
 /**
- * erase_worker - physical eraseblock erase worker function.
+ * __erase_worker - physical eraseblock erase worker function.
  * @ubi: UBI device description object
  * @wl_wrk: the work object
  * @shutdown: non-zero if the worker has to free memory and exit
@@ -1025,8 +1037,7 @@ out_unlock:
  * needed. Returns zero in case of success and a negative error code in case of
  * failure.
  */
-static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
-                       int shutdown)
+static int __erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk)
 {
        struct ubi_wl_entry *e = wl_wrk->e;
        int pnum = e->pnum;
@@ -1034,21 +1045,11 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
        int lnum = wl_wrk->lnum;
        int err, available_consumed = 0;
 
-       if (shutdown) {
-               dbg_wl("cancel erasure of PEB %d EC %d", pnum, e->ec);
-               kfree(wl_wrk);
-               wl_entry_destroy(ubi, e);
-               return 0;
-       }
-
        dbg_wl("erase PEB %d EC %d LEB %d:%d",
               pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);
 
        err = sync_erase(ubi, e, wl_wrk->torture);
        if (!err) {
-               /* Fine, we've erased it successfully */
-               kfree(wl_wrk);
-
                spin_lock(&ubi->wl_lock);
                wl_tree_add(e, &ubi->free);
                ubi->free_count++;
@@ -1066,7 +1067,6 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
        }
 
        ubi_err(ubi, "failed to erase PEB %d, error %d", pnum, err);
-       kfree(wl_wrk);
 
        if (err == -EINTR || err == -ENOMEM || err == -EAGAIN ||
            err == -EBUSY) {
@@ -1075,6 +1075,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
                /* Re-schedule the LEB for erasure */
                err1 = schedule_erase(ubi, e, vol_id, lnum, 0);
                if (err1) {
+                       wl_entry_destroy(ubi, e);
                        err = err1;
                        goto out_ro;
                }
@@ -1150,6 +1151,25 @@ out_ro:
        return err;
 }
 
+static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
+                         int shutdown)
+{
+       int ret;
+
+       if (shutdown) {
+               struct ubi_wl_entry *e = wl_wrk->e;
+
+               dbg_wl("cancel erasure of PEB %d EC %d", e->pnum, e->ec);
+               kfree(wl_wrk);
+               wl_entry_destroy(ubi, e);
+               return 0;
+       }
+
+       ret = __erase_worker(ubi, wl_wrk);
+       kfree(wl_wrk);
+       return ret;
+}
+
 /**
  * ubi_wl_put_peb - return a PEB to the wear-leveling sub-system.
  * @ubi: UBI device description object