linux-kernel - Re: [PATCH v2] media: atomisp: Fixed error handling path

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Date:   Thu, 19 Nov 2020 01:06:14 +0530
From:   Souptick Joarder <jrdr.linux@...il.com>
To:     mchehab@...nel.org, sakari.ailus@...ux.intel.com,
        Greg KH <gregkh@...uxfoundation.org>, gustavoars@...nel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>, daniel.m.jordan@...cle.com,
        Michel Lespinasse <walken@...gle.com>
Cc:     linux-media@...r.kernel.org,
        "open list:ANDROID DRIVERS" <devel@...verdev.osuosl.org>,
        linux-kernel@...r.kernel.org, John Hubbard <jhubbard@...dia.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH v2] media: atomisp: Fixed error handling path

On Wed, Nov 4, 2020 at 7:32 AM Souptick Joarder <jrdr.linux@...il.com> wrote:
>
> Inside alloc_user_pages() based on flag value either pin_user_pages()
> or get_user_pages_fast() will be called. However, these API might fail.
>
> But free_user_pages() called in error handling path doesn't bother
> about return value and will try to unpin bo->pgnr pages, which is
> incorrect.
>
> Fix this by passing the page_nr to free_user_pages(). If page_nr > 0
> pages will be unpinned based on bo->mem_type. This will also take care
> of non error handling path.
>
> Fixes: 14a638ab96c5 ("media: atomisp: use pin_user_pages() for memory
> allocation")
> Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
> Reviewed-by: Dan Carpenter <dan.carpenter@...cle.com>
> Cc: John Hubbard <jhubbard@...dia.com>
> Cc: Ira Weiny <ira.weiny@...el.com>
> Cc: Dan Carpenter <dan.carpenter@...cle.com>
> ---
> v2:
>     Added review tag.

Any further comment ? If no, can we get this patch in queue for 5.11 ?
>
>  drivers/staging/media/atomisp/pci/hmm/hmm_bo.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c b/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c
> index f13af23..0168f98 100644
> --- a/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c
> +++ b/drivers/staging/media/atomisp/pci/hmm/hmm_bo.c
> @@ -857,16 +857,17 @@ static void free_private_pages(struct hmm_buffer_object *bo,
>         kfree(bo->page_obj);
>  }
>
> -static void free_user_pages(struct hmm_buffer_object *bo)
> +static void free_user_pages(struct hmm_buffer_object *bo,
> +                           unsigned int page_nr)
>  {
>         int i;
>
>         hmm_mem_stat.usr_size -= bo->pgnr;
>
>         if (bo->mem_type == HMM_BO_MEM_TYPE_PFN) {
> -               unpin_user_pages(bo->pages, bo->pgnr);
> +               unpin_user_pages(bo->pages, page_nr);
>         } else {
> -               for (i = 0; i < bo->pgnr; i++)
> +               for (i = 0; i < page_nr; i++)
>                         put_page(bo->pages[i]);
>         }
>         kfree(bo->pages);
> @@ -942,6 +943,8 @@ static int alloc_user_pages(struct hmm_buffer_object *bo,
>                 dev_err(atomisp_dev,
>                         "get_user_pages err: bo->pgnr = %d, pgnr actually pinned = %d.\n",
>                         bo->pgnr, page_nr);
> +               if (page_nr < 0)
> +                       page_nr = 0;
>                 goto out_of_mem;
>         }
>
> @@ -954,7 +957,7 @@ static int alloc_user_pages(struct hmm_buffer_object *bo,
>
>  out_of_mem:
>
> -       free_user_pages(bo);
> +       free_user_pages(bo, page_nr);
>
>         return -ENOMEM;
>  }
> @@ -1037,7 +1040,7 @@ void hmm_bo_free_pages(struct hmm_buffer_object *bo)
>         if (bo->type == HMM_BO_PRIVATE)
>                 free_private_pages(bo, &dynamic_pool, &reserved_pool);
>         else if (bo->type == HMM_BO_USER)
> -               free_user_pages(bo);
> +               free_user_pages(bo, bo->pgnr);
>         else
>                 dev_err(atomisp_dev, "invalid buffer type.\n");
>         mutex_unlock(&bo->mutex);
> --
> 1.9.1
>