lightnvm: pblk: garbage collect lines with failed writes

Write failures should not happen under normal circumstances,
so in order to bring the chunk back into a known state as soon
as possible, evacuate all the valid data out of the line and let the
fw judge if the block can be written to in the next reset cycle.

Do this by introducing a new gc list for lines with failed writes,
and ensure that the rate limiter allocates a small portion of
the write bandwidth to get the job done.

The lba list is saved in memory for use during gc as we
cannot gurantee that the emeta data is readable if a write
error occurred.

Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 31 insertions, 15 deletions

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 2a3302f7e853..783887b891b7 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -493,11 +493,17 @@ static void pblk_line_mg_free(struct pblk *pblk)
         }
 }
 
-static void pblk_line_meta_free(struct pblk_line *line)
+static void pblk_line_meta_free(struct pblk_line_mgmt *l_mg,
+                                struct pblk_line *line)
 {
+        struct pblk_w_err_gc *w_err_gc = line->w_err_gc;
+
         kfree(line->blk_bitmap);
         kfree(line->erase_bitmap);
         kfree(line->chks);
+
+        pblk_mfree(w_err_gc->lba_list, l_mg->emeta_alloc_type);
+        kfree(w_err_gc);
 }
 
 static void pblk_lines_free(struct pblk *pblk)
@@ -511,7 +517,7 @@ static void pblk_lines_free(struct pblk *pblk)
                 line = &pblk->lines[i];
 
                 pblk_line_free(line);
-                pblk_line_meta_free(line);
+                pblk_line_meta_free(l_mg, line);
         }
         spin_unlock(&l_mg->free_lock);
 
@@ -813,20 +819,28 @@ static int pblk_alloc_line_meta(struct pblk *pblk, struct pblk_line *line)
                 return -ENOMEM;
 
         line->erase_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
-        if (!line->erase_bitmap) {
-                kfree(line->blk_bitmap);
-                return -ENOMEM;
-        }
+        if (!line->erase_bitmap)
+                goto free_blk_bitmap;
+
 
         line->chks = kmalloc(lm->blk_per_line * sizeof(struct nvm_chk_meta),
                                                                 GFP_KERNEL);
-        if (!line->chks) {
-                kfree(line->erase_bitmap);
-                kfree(line->blk_bitmap);
-                return -ENOMEM;
-        }
+        if (!line->chks)
+                goto free_erase_bitmap;
+
+        line->w_err_gc = kzalloc(sizeof(struct pblk_w_err_gc), GFP_KERNEL);
+        if (!line->w_err_gc)
+                goto free_chks;
 
         return 0;
+
+free_chks:
+        kfree(line->chks);
+free_erase_bitmap:
+        kfree(line->erase_bitmap);
+free_blk_bitmap:
+        kfree(line->blk_bitmap);
+        return -ENOMEM;
 }
 
 static int pblk_line_mg_init(struct pblk *pblk)
@@ -851,12 +865,14 @@ static int pblk_line_mg_init(struct pblk *pblk)
         INIT_LIST_HEAD(&l_mg->gc_mid_list);
         INIT_LIST_HEAD(&l_mg->gc_low_list);
         INIT_LIST_HEAD(&l_mg->gc_empty_list);
+        INIT_LIST_HEAD(&l_mg->gc_werr_list);
 
         INIT_LIST_HEAD(&l_mg->emeta_list);
 
-        l_mg->gc_lists[0] = &l_mg->gc_high_list;
-        l_mg->gc_lists[1] = &l_mg->gc_mid_list;
-        l_mg->gc_lists[2] = &l_mg->gc_low_list;
+        l_mg->gc_lists[0] = &l_mg->gc_werr_list;
+        l_mg->gc_lists[1] = &l_mg->gc_high_list;
+        l_mg->gc_lists[2] = &l_mg->gc_mid_list;
+        l_mg->gc_lists[3] = &l_mg->gc_low_list;
 
         spin_lock_init(&l_mg->free_lock);
         spin_lock_init(&l_mg->close_lock);
@@ -1063,7 +1079,7 @@ static int pblk_lines_init(struct pblk *pblk)
 
 fail_free_lines:
         while (--i >= 0)
-                pblk_line_meta_free(&pblk->lines[i]);
+                pblk_line_meta_free(l_mg, &pblk->lines[i]);
         kfree(pblk->lines);
 fail_free_chunk_meta:
         kfree(chunk_meta);