lightnvm: pblk: allocate line map bitmaps using a mempool

Line map bitmap allocations are fairly large and can fail. Allocation
failures are fatal to pblk, stopping the write pipeline. To avoid this,
allocate the bitmaps using a mempool instead.

Mempool allocations never fail if called from a process context,
and pblk *should* only allocate map bitmaps in process context,
but keep the failure handling for robustness sake.

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

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 8adc8ac8b03c..76a4a271b9cf 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -498,6 +498,9 @@ static void pblk_line_mg_free(struct pblk *pblk)
                 pblk_mfree(l_mg->eline_meta[i]->buf, l_mg->emeta_alloc_type);
                 kfree(l_mg->eline_meta[i]);
         }
+
+        mempool_destroy(l_mg->bitmap_pool);
+        kmem_cache_destroy(l_mg->bitmap_cache);
 }
 
 static void pblk_line_meta_free(struct pblk_line_mgmt *l_mg,
@@ -797,6 +800,17 @@ static int pblk_line_mg_init(struct pblk *pblk)
                         goto fail_free_smeta;
         }
 
+        l_mg->bitmap_cache = kmem_cache_create("pblk_lm_bitmap",
+                        lm->sec_bitmap_len, 0, 0, NULL);
+        if (!l_mg->bitmap_cache)
+                goto fail_free_smeta;
+
+        /* the bitmap pool is used for both valid and map bitmaps */
+        l_mg->bitmap_pool = mempool_create_slab_pool(PBLK_DATA_LINES * 2,
+                                l_mg->bitmap_cache);
+        if (!l_mg->bitmap_pool)
+                goto fail_destroy_bitmap_cache;
+
         /* emeta allocates three different buffers for managing metadata with
          * in-memory and in-media layouts
          */
@@ -849,6 +863,10 @@ fail_free_emeta:
                         kfree(l_mg->eline_meta[i]->buf);
                 kfree(l_mg->eline_meta[i]);
         }
+
+        mempool_destroy(l_mg->bitmap_pool);
+fail_destroy_bitmap_cache:
+        kmem_cache_destroy(l_mg->bitmap_cache);
 fail_free_smeta:
         for (i = 0; i < PBLK_DATA_LINES; i++)
                 kfree(l_mg->sline_meta[i]);