[PATCH v2] lightnvm: fix rrpc_lun_gc

[PATCH v2] lightnvm: fix rrpc_lun_gc

[Wenwei Tao]

This patch fix two issues in rrpc_lun_gc

1. prio_list is protected by rrpc_lun's lock not nvm_lun's, so
acquire rlun's lock instead of lun's before operate on the list.

2. we delete block from prio_list before allocating gcb, but gcb
allocation may fail, we end without putting it back to the list,
this makes the block won't get reclaimed in the future. To solve
this issue, delete block after gcb allocation.

Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
---

Changed in v2:
 -Advance the gcb allocation, make the debug log deliver
the correct message. 

 drivers/lightnvm/rrpc.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/lightnvm/rrpc.c b/drivers/lightnvm/rrpc.c
index 67b14d4..40b0309 100644
--- a/drivers/lightnvm/rrpc.c
+++ b/drivers/lightnvm/rrpc.c
@@ -443,7 +443,7 @@ static void rrpc_lun_gc(struct work_struct *work)
 	if (nr_blocks_need < rrpc->nr_luns)
 		nr_blocks_need = rrpc->nr_luns;
 
-	spin_lock(&lun->lock);
+	spin_lock(&rlun->lock);
 	while (nr_blocks_need > lun->nr_free_blocks &&
 					!list_empty(&rlun->prio_list)) {
 		struct rrpc_block *rblock = block_prio_find_max(rlun);
@@ -452,16 +452,16 @@ static void rrpc_lun_gc(struct work_struct *work)
 		if (!rblock->nr_invalid_pages)
 			break;
 
+		gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
+		if (!gcb)
+			break;
+
 		list_del_init(&rblock->prio);
 
 		BUG_ON(!block_is_full(rrpc, rblock));
 
 		pr_debug("rrpc: selected block '%lu' for GC\n", block->id);
 
-		gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
-		if (!gcb)
-			break;
-
 		gcb->rrpc = rrpc;
 		gcb->rblk = rblock;
 		INIT_WORK(&gcb->ws_gc, rrpc_block_gc);
@@ -470,7 +470,7 @@ static void rrpc_lun_gc(struct work_struct *work)
 
 		nr_blocks_need--;
 	}
-	spin_unlock(&lun->lock);
+	spin_unlock(&rlun->lock);
 
 	/* TODO: Hint that request queue can be started again */
 }
-- 
1.8.3.1

Re: [PATCH v2] lightnvm: fix rrpc_lun_gc

[Matias Bjørling]

On 12/31/2015 05:40 AM, Wenwei Tao wrote:
> This patch fix two issues in rrpc_lun_gc
>
> 1. prio_list is protected by rrpc_lun's lock not nvm_lun's, so
> acquire rlun's lock instead of lun's before operate on the list.
>
> 2. we delete block from prio_list before allocating gcb, but gcb
> allocation may fail, we end without putting it back to the list,
> this makes the block won't get reclaimed in the future. To solve
> this issue, delete block after gcb allocation.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
> ---
>
> Changed in v2:
>   -Advance the gcb allocation, make the debug log deliver
> the correct message.
>
>   drivers/lightnvm/rrpc.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/lightnvm/rrpc.c b/drivers/lightnvm/rrpc.c
> index 67b14d4..40b0309 100644
> --- a/drivers/lightnvm/rrpc.c
> +++ b/drivers/lightnvm/rrpc.c
> @@ -443,7 +443,7 @@ static void rrpc_lun_gc(struct work_struct *work)
>   	if (nr_blocks_need < rrpc->nr_luns)
>   		nr_blocks_need = rrpc->nr_luns;
>
> -	spin_lock(&lun->lock);
> +	spin_lock(&rlun->lock);
>   	while (nr_blocks_need > lun->nr_free_blocks &&
>   					!list_empty(&rlun->prio_list)) {
>   		struct rrpc_block *rblock = block_prio_find_max(rlun);
> @@ -452,16 +452,16 @@ static void rrpc_lun_gc(struct work_struct *work)
>   		if (!rblock->nr_invalid_pages)
>   			break;
>
> +		gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
> +		if (!gcb)
> +			break;
> +
>   		list_del_init(&rblock->prio);
>
>   		BUG_ON(!block_is_full(rrpc, rblock));
>
>   		pr_debug("rrpc: selected block '%lu' for GC\n", block->id);
>
> -		gcb = mempool_alloc(rrpc->gcb_pool, GFP_ATOMIC);
> -		if (!gcb)
> -			break;
> -
>   		gcb->rrpc = rrpc;
>   		gcb->rblk = rblock;
>   		INIT_WORK(&gcb->ws_gc, rrpc_block_gc);
> @@ -470,7 +470,7 @@ static void rrpc_lun_gc(struct work_struct *work)
>
>   		nr_blocks_need--;
>   	}
> -	spin_unlock(&lun->lock);
> +	spin_unlock(&rlun->lock);
>
>   	/* TODO: Hint that request queue can be started again */
>   }
>
Thanks, applied for 4.5. I've changed the title a bit.