Re: [PATCH] misc: mic: fix incorrect use of error codes in SCIF DMA driver

From: Sudeep Dutt
Date: Fri Dec 11 2015 - 21:53:23 EST


On Fri, 2015-12-11 at 20:09 -0600, Eric Biggers wrote:
> The error code passed to ERR_PTR() always should be negated. Also, the
> return value of scif_add_mmu_notifier() was never checked.
>

Thanks for the patch Eric.

Reviewed-by: Sudeep Dutt <sudeep.dutt@xxxxxxxxx>

> Signed-off-by: Eric Biggers <ebiggers3@xxxxxxxxx>
> ---
> drivers/misc/mic/scif/scif_dma.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/misc/mic/scif/scif_dma.c b/drivers/misc/mic/scif/scif_dma.c
> index 95a13c6..f6aeebd 100644
> --- a/drivers/misc/mic/scif/scif_dma.c
> +++ b/drivers/misc/mic/scif/scif_dma.c
> @@ -276,13 +276,10 @@ static struct scif_mmu_notif *
> scif_find_mmu_notifier(struct mm_struct *mm, struct scif_endpt_rma_info *rma)
> {
> struct scif_mmu_notif *mmn;
> - struct list_head *item;
>
> - list_for_each(item, &rma->mmn_list) {
> - mmn = list_entry(item, struct scif_mmu_notif, list);
> + list_for_each_entry(mmn, &rma->mmn_list, list)
> if (mmn->mm == mm)
> return mmn;
> - }
> return NULL;
> }
>
> @@ -293,13 +290,12 @@ scif_add_mmu_notifier(struct mm_struct *mm, struct scif_endpt *ep)
> = kzalloc(sizeof(*mmn), GFP_KERNEL);
>
> if (!mmn)
> - return ERR_PTR(ENOMEM);
> + return ERR_PTR(-ENOMEM);
>
> scif_init_mmu_notifier(mmn, current->mm, ep);
> - if (mmu_notifier_register(&mmn->ep_mmu_notifier,
> - current->mm)) {
> + if (mmu_notifier_register(&mmn->ep_mmu_notifier, current->mm)) {
> kfree(mmn);
> - return ERR_PTR(EBUSY);
> + return ERR_PTR(-EBUSY);
> }
> list_add(&mmn->list, &ep->rma_info.mmn_list);
> return mmn;
> @@ -1730,7 +1726,7 @@ static int scif_rma_copy(scif_epd_t epd, off_t loffset, unsigned long addr,
> mutex_lock(&ep->rma_info.mmn_lock);
> mmn = scif_find_mmu_notifier(current->mm, &ep->rma_info);
> if (!mmn)
> - scif_add_mmu_notifier(current->mm, ep);
> + mmn = scif_add_mmu_notifier(current->mm, ep);
> mutex_unlock(&ep->rma_info.mmn_lock);
> if (IS_ERR(mmn)) {
> scif_put_peer_dev(spdev);


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