Re: [PATCH V3] lightnvm: if LUNs are already allocated fix return

[Frans Klaver]

On Tue, Jun 27, 2017 at 1:55 PM, Rakesh Pandit <rak...@tuxera.com> wrote:
> While creating new device with NVM_DEV_CREATE if LUNs are already
> allocated ioctl would return -ENOMEM which is wrong.  This patch
> propagates -EBUSY from nvm_reserve_luns which is correct response.
>
> Fixes: ade69e243 ("lightnvm: merge gennvm with core")
> Signed-off-by: Rakesh Pandit <rak...@tuxera.com>

Reviewed-by: Frans Klaver <franskla...@gmail.com>

> ---
>
> V3: Propagate return value from nvm_reserve_luns instead of hard-coding 
> (Frans)
> V2: return error code directly instead of using ret variable (Frans)
>
>  drivers/lightnvm/core.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index b8f82f5..ddae430 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -252,8 +252,9 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct 
> nvm_ioctl_create *create)
> }
> mutex_unlock(>mlock);
>
> -   if (nvm_reserve_luns(dev, s->lun_begin, s->lun_end))
> -   return -ENOMEM;
> +   ret = nvm_reserve_luns(dev, s->lun_begin, s->lun_end);
> +   if (ret)
> +   return ret;
>
> t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
> if (!t) {
> --
> 2.5.5
>

Re: [PATCH V2] lightnvm: if LUNs are already allocated fix return

[Frans Klaver]

On Tue, Jun 27, 2017 at 1:23 PM, Rakesh Pandit <rak...@tuxera.com> wrote:
> On Tue, Jun 27, 2017 at 01:01:22PM +0200, Frans Klaver wrote:
>> On Tue, Jun 27, 2017 at 12:43 PM, Rakesh Pandit <rak...@tuxera.com> wrote:
>> > While creating new device with NVM_DEV_CREATE if LUNs are already
>> > allocated ioctl would return -ENOMEM which is wrong.  This patch
>> > propagates -EBUSY from nvm_reserve_luns which is correct response.
>> >
>> > Fixes: ade69e243 ("lightnvm: merge gennvm with core")
>> > Signed-off-by: Rakesh Pandit <rak...@tuxera.com>
>> > ---
>> >
>> > V2: return error code directly instead of using ret variable (Frans)
>> >
>> >  drivers/lightnvm/core.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
>> > index b8f82f5..c5d71c6 100644
>> > --- a/drivers/lightnvm/core.c
>> > +++ b/drivers/lightnvm/core.c
>> > @@ -253,7 +253,7 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct 
>> > nvm_ioctl_create *create)
>> > mutex_unlock(>mlock);
>> >
>> > if (nvm_reserve_luns(dev, s->lun_begin, s->lun_end))
>> > -   return -ENOMEM;
>> > +   return -EBUSY;
>>
>> Why aren't you propagating ret in this version?
>
> Well nvm_reserve_luns either returns 0 or -EBUSY and it is unlikely
> that return value would change and even if it does this can be
> updated.

If you propagate the result of nvm_reserve_luns(), the casual reader
will immediately understand that any possible faulty result is
returned. returning -EBUSY here might suggest you're overriding
whatever this function returns.

Re: [PATCH V2] lightnvm: if LUNs are already allocated fix return

[Frans Klaver]

On Tue, Jun 27, 2017 at 12:43 PM, Rakesh Pandit  wrote:
> While creating new device with NVM_DEV_CREATE if LUNs are already
> allocated ioctl would return -ENOMEM which is wrong.  This patch
> propagates -EBUSY from nvm_reserve_luns which is correct response.
>
> Fixes: ade69e243 ("lightnvm: merge gennvm with core")
> Signed-off-by: Rakesh Pandit 
> ---
>
> V2: return error code directly instead of using ret variable (Frans)
>
>  drivers/lightnvm/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index b8f82f5..c5d71c6 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -253,7 +253,7 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct 
> nvm_ioctl_create *create)
> mutex_unlock(>mlock);
>
> if (nvm_reserve_luns(dev, s->lun_begin, s->lun_end))
> -   return -ENOMEM;
> +   return -EBUSY;

Why aren't you propagating ret in this version?

Re: [PATCH] ligtnvm: if LUNs are already allocated fix return

[Frans Klaver]

On Tue, Jun 27, 2017 at 10:39 AM, Matias Bjørling  wrote:
> From: Rakesh Pandit 
>
> While creating new device with NVM_DEV_CREATE if LUNs are already
> allocated ioctl would return -ENOMEM which is wrong.  This patch
> propagates -EBUSY from nvm_reserve_luns which is correct response.
>
> Fixes: ade69e243 ("lightnvm: merge gennvm with core")
> Signed-off-by: Rakesh Pandit 
> Signed-off-by: Matias Bjørling 
> ---
>  drivers/lightnvm/core.c | 11 ++-
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index b8f82f5..9ff348f 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -235,7 +235,7 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct 
> nvm_ioctl_create *create)
> struct nvm_target *t;
> struct nvm_tgt_dev *tgt_dev;
> void *targetdata;
> -   int ret;
> +   int ret = 0;

Is there any way that you can reach a 'return ret' without having ret
set by some other assignment?


> tt = nvm_find_target_type(create->tgttype, 1);
> if (!tt) {
> @@ -252,8 +252,9 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct 
> nvm_ioctl_create *create)
> }
> mutex_unlock(>mlock);
>
> -   if (nvm_reserve_luns(dev, s->lun_begin, s->lun_end))
> -   return -ENOMEM;
> +   ret = nvm_reserve_luns(dev, s->lun_begin, s->lun_end);
> +   if (ret)
> +   goto err;

Why don't you return err straight away here?


> t = kmalloc(sizeof(struct nvm_target), GFP_KERNEL);
> if (!t) {
> @@ -314,8 +315,8 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct 
> nvm_ioctl_create *create)
> mutex_lock(>mlock);
> list_add_tail(>list, >targets);
> mutex_unlock(>mlock);
> -
> -   return 0;
> +err:
> +   return ret;

This should not be necessary. In any case, the de-init order should
always be the reverse of the init order, so we don't end up confused.

Frans