Re: [PATCH 3/3] drivers/misc/sgi-gru: fix return of error

Dimitri Sivanich
2015-09-26T12:44:38Z

Acked-by: Dimitri Sivanich <sivanich@sgi.com>

On Mon, Sep 21, 2015 at 03:48:19PM +0530, Sudip Mukherjee wrote:
> If kzalloc() fails then gms is NULL and we are returning NULL, but the
> functions which called this function gru_register_mmu_notifier() are not
> expecting NULL as the return. They are expecting either a valid pointer
> or the error code in ERR_PTR.
>
> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
> ---
>
> The patch at https://patchwork.kernel.org/patch/6394911/ is not applied
> and not relevant now as gms is checked before gru_dbg. But the idea for
> this patch was obtained from that one.
>
> drivers/misc/sgi-gru/grutlbpurge.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/misc/sgi-gru/grutlbpurge.c b/drivers/misc/sgi-gru/grutlbpurge.c
> index 757a8e9..e936d43 100644
> --- a/drivers/misc/sgi-gru/grutlbpurge.c
> +++ b/drivers/misc/sgi-gru/grutlbpurge.c
> @@ -306,16 +306,16 @@ struct gru_mm_struct *gru_register_mmu_notifier(void)
> atomic_inc(&gms->ms_refcnt);
> } else {
> gms = kzalloc(sizeof(*gms), GFP_KERNEL);
> - if (gms) {
> - STAT(gms_alloc);
> - spin_lock_init(&gms->ms_asid_lock);
> - gms->ms_notifier.ops = &gru_mmuops;
> - atomic_set(&gms->ms_refcnt, 1);
> - init_waitqueue_head(&gms->ms_wait_queue);
> - err = __mmu_notifier_register(&gms->ms_notifier, current->mm);
> - if (err)
> - goto error;
> - }
> + if (!gms)
> + return ERR_PTR(-ENOMEM);
> + STAT(gms_alloc);
> + spin_lock_init(&gms->ms_asid_lock);
> + gms->ms_notifier.ops = &gru_mmuops;
> + atomic_set(&gms->ms_refcnt, 1);
> + init_waitqueue_head(&gms->ms_wait_queue);
> + err = __mmu_notifier_register(&gms->ms_notifier, current->mm);
> + if (err)
> + goto error;
> }
> if (gms)
> gru_dbg(grudev, "gms %p, refcnt %d\n", gms,
> --
> 1.9.1