[PATCH] lightnvm: pblk: fix rqd.error return value in pblk_blk_erase_sync

[PATCH] lightnvm: pblk: fix rqd.error return value in pblk_blk_erase_sync

[Matias Bjørling]

rqd.error is masked by the return value of pblk_submit_io_sync.
The rqd structure is then passed on to the end_io function, which
assumes that any error should lead to a chunk being marked
offline/bad. Since the pblk_submit_io_sync can fail before the
command is issued to the device, the error value maybe not correspond
to a media failure, leading to chunks being immaturely retired.

Also, the pblk_blk_erase_sync function prints an error message in case
the erase fails. Since the caller prints an error message by itself,
remove the error message in this function.

Signed-off-by: Matias Bjørling <mb@lightnvm.io>
---
 drivers/lightnvm/pblk-core.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
index 72acf2f6dbd6..814204d22a2e 100644
--- a/drivers/lightnvm/pblk-core.c
+++ b/drivers/lightnvm/pblk-core.c
@@ -886,10 +886,8 @@ static void pblk_setup_e_rq(struct pblk *pblk, struct nvm_rq *rqd,
 
 static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
 {
-	struct nvm_rq rqd;
-	int ret = 0;
-
-	memset(&rqd, 0, sizeof(struct nvm_rq));
+	struct nvm_rq rqd = {0};
+	int ret;
 
 	pblk_setup_e_rq(pblk, &rqd, ppa);
 
@@ -897,19 +895,6 @@ static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
 	 * with writes. Thus, there is no need to take the LUN semaphore.
 	 */
 	ret = pblk_submit_io_sync(pblk, &rqd);
-	if (ret) {
-		struct nvm_tgt_dev *dev = pblk->dev;
-		struct nvm_geo *geo = &dev->geo;
-
-		pblk_err(pblk, "could not sync erase line:%d,blk:%d\n",
-					pblk_ppa_to_line(ppa),
-					pblk_ppa_to_pos(geo, ppa));
-
-		rqd.error = ret;
-		goto out;
-	}
-
-out:
 	rqd.private = pblk;
 	__pblk_end_io_erase(pblk, &rqd);
 
-- 
2.11.0

Re: [PATCH] lightnvm: pblk: fix rqd.error return value in pblk_blk_erase_sync

[Javier Gonzalez]

[-- Attachment #1: Type: text/plain, Size: 2331 bytes --]

> On 2 Aug 2018, at 22.50, Matias Bjørling <mb@lightnvm.io> wrote:
> 
> rqd.error is masked by the return value of pblk_submit_io_sync.
> The rqd structure is then passed on to the end_io function, which
> assumes that any error should lead to a chunk being marked
> offline/bad. Since the pblk_submit_io_sync can fail before the
> command is issued to the device, the error value maybe not correspond
> to a media failure, leading to chunks being immaturely retired.
> 
> Also, the pblk_blk_erase_sync function prints an error message in case
> the erase fails. Since the caller prints an error message by itself,
> remove the error message in this function.
> 
> Signed-off-by: Matias Bjørling <mb@lightnvm.io>
> ---
> drivers/lightnvm/pblk-core.c | 19 ++-----------------
> 1 file changed, 2 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index 72acf2f6dbd6..814204d22a2e 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -886,10 +886,8 @@ static void pblk_setup_e_rq(struct pblk *pblk, struct nvm_rq *rqd,
> 
> static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
> {
> -	struct nvm_rq rqd;
> -	int ret = 0;
> -
> -	memset(&rqd, 0, sizeof(struct nvm_rq));
> +	struct nvm_rq rqd = {0};

This is a matter of taste, but if you want to squeeze it in here, it is
fine by me. There are other places with the same pattern; if you feel
strongly about this then please send a patch changing it in all the
places.

> +	int ret;
> 
> 	pblk_setup_e_rq(pblk, &rqd, ppa);
> 
> @@ -897,19 +895,6 @@ static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
> 	 * with writes. Thus, there is no need to take the LUN semaphore.
> 	 */
> 	ret = pblk_submit_io_sync(pblk, &rqd);
> -	if (ret) {
> -		struct nvm_tgt_dev *dev = pblk->dev;
> -		struct nvm_geo *geo = &dev->geo;
> -
> -		pblk_err(pblk, "could not sync erase line:%d,blk:%d\n",
> -					pblk_ppa_to_line(ppa),
> -					pblk_ppa_to_pos(geo, ppa));
> -
> -		rqd.error = ret;
> -		goto out;
> -	}
> -
> -out:
> 	rqd.private = pblk;
> 	__pblk_end_io_erase(pblk, &rqd);
> 
> --
> 2.11.0

Otherwise, it looks like a good cleanup. Thanks.

Reviewed-by: Javier González <javier@cnexlabs.com>


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Re: [PATCH] lightnvm: pblk: fix rqd.error return value in pblk_blk_erase_sync

[Hans Holmberg]

On Thu, Aug 2, 2018 at 10:50 PM, Matias Bjørling <mb@lightnvm.io> wrote:
> rqd.error is masked by the return value of pblk_submit_io_sync.
> The rqd structure is then passed on to the end_io function, which
> assumes that any error should lead to a chunk being marked
> offline/bad. Since the pblk_submit_io_sync can fail before the
> command is issued to the device, the error value maybe not correspond
> to a media failure, leading to chunks being immaturely retired.
>
> Also, the pblk_blk_erase_sync function prints an error message in case
> the erase fails. Since the caller prints an error message by itself,
> remove the error message in this function.
>
> Signed-off-by: Matias Bjørling <mb@lightnvm.io>
> ---
>  drivers/lightnvm/pblk-core.c | 19 ++-----------------
>  1 file changed, 2 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c
> index 72acf2f6dbd6..814204d22a2e 100644
> --- a/drivers/lightnvm/pblk-core.c
> +++ b/drivers/lightnvm/pblk-core.c
> @@ -886,10 +886,8 @@ static void pblk_setup_e_rq(struct pblk *pblk, struct nvm_rq *rqd,
>
>  static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
>  {
> -       struct nvm_rq rqd;
> -       int ret = 0;
> -
> -       memset(&rqd, 0, sizeof(struct nvm_rq));
> +       struct nvm_rq rqd = {0};
> +       int ret;
>
>         pblk_setup_e_rq(pblk, &rqd, ppa);
>
> @@ -897,19 +895,6 @@ static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
>          * with writes. Thus, there is no need to take the LUN semaphore.
>          */
>         ret = pblk_submit_io_sync(pblk, &rqd);
> -       if (ret) {
> -               struct nvm_tgt_dev *dev = pblk->dev;
> -               struct nvm_geo *geo = &dev->geo;
> -
> -               pblk_err(pblk, "could not sync erase line:%d,blk:%d\n",
> -                                       pblk_ppa_to_line(ppa),
> -                                       pblk_ppa_to_pos(geo, ppa));
> -
> -               rqd.error = ret;
> -               goto out;
> -       }
> -
> -out:
>         rqd.private = pblk;
>         __pblk_end_io_erase(pblk, &rqd);
>
> --
> 2.11.0
>


Nice catch! I just added fixing this exact issue in my own backlog,
great that you've already fixed it.

Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com>