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

[Frans Klaver]

On Tue, Jun 27, 2017 at 1:23 PM, Rakesh Pandit <rakesh@xxxxxxxxxx> 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 <rakesh@xxxxxxxxxx> 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 <rakesh@xxxxxxxxxx>
>> > ---
>> >
>> > 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(&dev->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.