From: =?UTF-8?q?Javier=20Gonz=C3=A1lez?= <javier@cnexlabs.com>
Date: Fri, 13 Oct 2017 14:46:09 +0200
Subject: [PATCH] lightnvm: pblk: do not use a mempool for line bitmaps
Git-commit: e72ec1d31bcb6dffe325418c6d96f2fcab7c2654
Patch-mainline: v4.15-rc1
References: bsc#1104967,FATE#325924
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

pblk holds two sector bitmaps: one to keep track of the mapped sectors
while the line is active and another one to keep track of the invalid
sectors. The latter is kept during the whole live of the line, until it
is recycled. Since we cannot guarantee forward progress for the mempool
in this case, get rid of the mempool and simply allocate memory through
kmalloc.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/lightnvm/pblk-core.c     | 26 ++++++++++----------------
 drivers/lightnvm/pblk-init.c     | 29 ++---------------------------
 drivers/lightnvm/pblk-recovery.c |  2 +-
 drivers/lightnvm/pblk-write.c    |  4 +---
 drivers/lightnvm/pblk.h          |  3 ---
 5 files changed, 14 insertions(+), 50 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 0c22e5ccdfdd..215aadb84c6e 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -1095,25 +1095,21 @@ static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
 	struct pblk_line_meta *lm = &pblk->lm;
 	int blk_in_line = atomic_read(&line->blk_in_line);
 
-	line->map_bitmap = mempool_alloc(pblk->line_meta_pool, GFP_ATOMIC);
+	line->map_bitmap = kzalloc(lm->sec_bitmap_len, GFP_ATOMIC);
 	if (!line->map_bitmap)
 		return -ENOMEM;
-	memset(line->map_bitmap, 0, lm->sec_bitmap_len);
 
-	/* invalid_bitmap is special since it is used when line is closed. No
-	 * need to zeroized; it will be initialized using bb info form
-	 * map_bitmap
-	 */
-	line->invalid_bitmap = mempool_alloc(pblk->line_meta_pool, GFP_ATOMIC);
+	/* will be initialized using bb info from map_bitmap */
+	line->invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_ATOMIC);
 	if (!line->invalid_bitmap) {
-		mempool_free(line->map_bitmap, pblk->line_meta_pool);
+		kfree(line->map_bitmap);
 		return -ENOMEM;
 	}
 
 	spin_lock(&line->lock);
 	if (line->state != PBLK_LINESTATE_FREE) {
-		mempool_free(line->invalid_bitmap, pblk->line_meta_pool);
-		mempool_free(line->map_bitmap, pblk->line_meta_pool);
+		kfree(line->map_bitmap);
+		kfree(line->invalid_bitmap);
 		spin_unlock(&line->lock);
 		WARN(1, "pblk: corrupted line %d, state %d\n",
 							line->id, line->state);
@@ -1165,7 +1161,7 @@ int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line)
 
 void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line)
 {
-	mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	kfree(line->map_bitmap);
 	line->map_bitmap = NULL;
 	line->smeta = NULL;
 	line->emeta = NULL;
@@ -1440,10 +1436,8 @@ void pblk_line_replace_data(struct pblk *pblk)
 
 void pblk_line_free(struct pblk *pblk, struct pblk_line *line)
 {
-	if (line->map_bitmap)
-		mempool_free(line->map_bitmap, pblk->line_meta_pool);
-	if (line->invalid_bitmap)
-		mempool_free(line->invalid_bitmap, pblk->line_meta_pool);
+	kfree(line->map_bitmap);
+	kfree(line->invalid_bitmap);
 
 	*line->vsc = cpu_to_le32(EMPTY_ENTRY);
 
@@ -1584,7 +1578,7 @@ void pblk_line_close(struct pblk *pblk, struct pblk_line *line)
 
 	list_add_tail(&line->list, move_list);
 
-	mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	kfree(line->map_bitmap);
 	line->map_bitmap = NULL;
 	line->smeta = NULL;
 	line->emeta = NULL;
diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index 2f8d3f9ffbaf..4d719782f65b 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -21,7 +21,7 @@
 #include "pblk.h"
 
 static struct kmem_cache *pblk_ws_cache, *pblk_rec_cache, *pblk_g_rq_cache,
-				*pblk_w_rq_cache, *pblk_line_meta_cache;
+				*pblk_w_rq_cache;
 static DECLARE_RWSEM(pblk_lock);
 struct bio_set *pblk_bio_set;
 
@@ -181,8 +181,6 @@ static int pblk_set_ppaf(struct pblk *pblk)
 
 static int pblk_init_global_caches(struct pblk *pblk)
 {
-	char cache_name[PBLK_CACHE_NAME_LEN];
-
 	down_write(&pblk_lock);
 	pblk_ws_cache = kmem_cache_create("pblk_blk_ws",
 				sizeof(struct pblk_line_ws), 0, 0, NULL);
@@ -217,19 +215,6 @@ static int pblk_init_global_caches(struct pblk *pblk)
 		up_write(&pblk_lock);
 		return -ENOMEM;
 	}
-
-	snprintf(cache_name, sizeof(cache_name), "pblk_line_m_%s",
-							pblk->disk->disk_name);
-	pblk_line_meta_cache = kmem_cache_create(cache_name,
-				pblk->lm.sec_bitmap_len, 0, 0, NULL);
-	if (!pblk_line_meta_cache) {
-		kmem_cache_destroy(pblk_ws_cache);
-		kmem_cache_destroy(pblk_rec_cache);
-		kmem_cache_destroy(pblk_g_rq_cache);
-		kmem_cache_destroy(pblk_w_rq_cache);
-		up_write(&pblk_lock);
-		return -ENOMEM;
-	}
 	up_write(&pblk_lock);
 
 	return 0;
@@ -276,16 +261,10 @@ static int pblk_core_init(struct pblk *pblk)
 	if (!pblk->w_rq_pool)
 		goto free_e_rq_pool;
 
-	pblk->line_meta_pool =
-			mempool_create_slab_pool(PBLK_META_POOL_SIZE,
-							pblk_line_meta_cache);
-	if (!pblk->line_meta_pool)
-		goto free_w_rq_pool;
-
 	pblk->close_wq = alloc_workqueue("pblk-close-wq",
 			WQ_MEM_RECLAIM | WQ_UNBOUND, PBLK_NR_CLOSE_JOBS);
 	if (!pblk->close_wq)
-		goto free_line_meta_pool;
+		goto free_w_rq_pool;
 
 	pblk->bb_wq = alloc_workqueue("pblk-bb-wq",
 			WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
@@ -305,8 +284,6 @@ static int pblk_core_init(struct pblk *pblk)
 	destroy_workqueue(pblk->bb_wq);
 free_close_wq:
 	destroy_workqueue(pblk->close_wq);
-free_line_meta_pool:
-	mempool_destroy(pblk->line_meta_pool);
 free_w_rq_pool:
 	mempool_destroy(pblk->w_rq_pool);
 free_e_rq_pool:
@@ -336,13 +313,11 @@ static void pblk_core_free(struct pblk *pblk)
 	mempool_destroy(pblk->r_rq_pool);
 	mempool_destroy(pblk->e_rq_pool);
 	mempool_destroy(pblk->w_rq_pool);
-	mempool_destroy(pblk->line_meta_pool);
 
 	kmem_cache_destroy(pblk_ws_cache);
 	kmem_cache_destroy(pblk_rec_cache);
 	kmem_cache_destroy(pblk_g_rq_cache);
 	kmem_cache_destroy(pblk_w_rq_cache);
-	kmem_cache_destroy(pblk_line_meta_cache);
 }
 
 static void pblk_luns_free(struct pblk *pblk)
diff --git a/drivers/lightnvm/pblk-recovery.c b/drivers/lightnvm/pblk-recovery.c
index caf124279575..de5270712be7 100644
--- a/drivers/lightnvm/pblk-recovery.c
+++ b/drivers/lightnvm/pblk-recovery.c
@@ -987,7 +987,7 @@ struct pblk_line *pblk_recov_l2p(struct pblk *pblk)
 			list_move_tail(&line->list, move_list);
 			spin_unlock(&l_mg->gc_lock);
 
-			mempool_free(line->map_bitmap, pblk->line_meta_pool);
+			kfree(line->map_bitmap);
 			line->map_bitmap = NULL;
 			line->smeta = NULL;
 			line->emeta = NULL;
diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index c73b17bca06b..26c2b8345149 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -411,8 +411,6 @@ int pblk_submit_meta_io(struct pblk *pblk, struct pblk_line *meta_line)
 	if (emeta->mem >= lm->emeta_len[0]) {
 		spin_lock(&l_mg->close_lock);
 		list_del(&meta_line->list);
-		WARN(!bitmap_full(meta_line->map_bitmap, lm->sec_per_line),
-				"pblk: corrupt meta line %d\n", meta_line->id);
 		spin_unlock(&l_mg->close_lock);
 	}
 
@@ -456,7 +454,7 @@ static int pblk_sched_meta_io(struct pblk *pblk, struct ppa_addr *prev_list,
 		return 0;
 	}
 	meta_line = list_first_entry(&l_mg->emeta_list, struct pblk_line, list);
-	if (bitmap_full(meta_line->map_bitmap, lm->sec_per_line))
+	if (meta_line->emeta->mem >= lm->emeta_len[0])
 		goto retry;
 	spin_unlock(&l_mg->close_lock);
 
diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
index 419e1b7328e4..60edcda0fc7f 100644
--- a/drivers/lightnvm/pblk.h
+++ b/drivers/lightnvm/pblk.h
@@ -40,8 +40,6 @@
 #define PBLK_MAX_REQ_ADDRS (64)
 #define PBLK_MAX_REQ_ADDRS_PW (6)
 
-#define PBLK_META_POOL_SIZE (128)
-
 #define PBLK_NR_CLOSE_JOBS (4)
 
 #define PBLK_CACHE_NAME_LEN (DISK_NAME_LEN + 16)
@@ -627,7 +625,6 @@ struct pblk {
 	mempool_t *r_rq_pool;
 	mempool_t *w_rq_pool;
 	mempool_t *e_rq_pool;
-	mempool_t *line_meta_pool;
 
 	struct workqueue_struct *close_wq;
 	struct workqueue_struct *bb_wq;
-- 
2.12.3