[Mesa-dev] [PATCH v4 1/2] gallium/winsys/kms: Fix possible leak in map/unmap.

[Lepton Wu]

Ping.  Any more comments or missing stuff to get this commited into master?

Thanks.

On Wed, Mar 7, 2018 at 2:39 PM, Lepton Wu <lepton at chromium.org> wrote:
> If user calls map twice for kms_sw_displaytarget, the first mapped
> buffer could get leaked. Instead of calling mmap every time, just
> reuse previous mapping. Since user could map same displaytarget with
> different flags, we have to keep two different pointers, one for rw
> mapping and one for ro mapping.
>
> Change-Id: I65308f0ff2640bd57b2577c6a3469540c9722859
> Signed-off-by: Lepton Wu <lepton at chromium.org>
> ---
>  .../winsys/sw/kms-dri/kms_dri_sw_winsys.c     | 21 ++++++++++++-------
>  1 file changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c b/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> index 22e1c936ac5..7fc40488c2e 100644
> --- a/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> +++ b/src/gallium/winsys/sw/kms-dri/kms_dri_sw_winsys.c
> @@ -70,6 +70,7 @@ struct kms_sw_displaytarget
>
>     uint32_t handle;
>     void *mapped;
> +   void *ro_mapped;
>
>     int ref_count;
>     struct list_head link;
> @@ -198,16 +199,19 @@ kms_sw_displaytarget_map(struct sw_winsys *ws,
>        return NULL;
>
>     prot = (flags == PIPE_TRANSFER_READ) ? PROT_READ : (PROT_READ | PROT_WRITE);
> -   kms_sw_dt->mapped = mmap(0, kms_sw_dt->size, prot, MAP_SHARED,
> -                            kms_sw->fd, map_req.offset);
> -
> -   if (kms_sw_dt->mapped == MAP_FAILED)
> -      return NULL;
> +   void **ptr = (flags == PIPE_TRANSFER_READ) ? &kms_sw_dt->ro_mapped : &kms_sw_dt->mapped;
> +   if (!*ptr) {
> +      void *tmp = mmap(0, kms_sw_dt->size, prot, MAP_SHARED,
> +                       kms_sw->fd, map_req.offset);
> +      if (tmp == MAP_FAILED)
> +         return NULL;
> +      *ptr = tmp;
> +   }
>
>     DEBUG_PRINT("KMS-DEBUG: mapped buffer %u (size %u) at %p\n",
> -         kms_sw_dt->handle, kms_sw_dt->size, kms_sw_dt->mapped);
> +         kms_sw_dt->handle, kms_sw_dt->size, *ptr);
>
> -   return kms_sw_dt->mapped;
> +   return *ptr;
>  }
>
>  static struct kms_sw_displaytarget *
> @@ -278,9 +282,12 @@ kms_sw_displaytarget_unmap(struct sw_winsys *ws,
>     struct kms_sw_displaytarget *kms_sw_dt = kms_sw_displaytarget(dt);
>
>     DEBUG_PRINT("KMS-DEBUG: unmapped buffer %u (was %p)\n", kms_sw_dt->handle, kms_sw_dt->mapped);
> +   DEBUG_PRINT("KMS-DEBUG: unmapped buffer %u (was %p)\n", kms_sw_dt->handle, kms_sw_dt->ro_mapped);
>
>     munmap(kms_sw_dt->mapped, kms_sw_dt->size);
>     kms_sw_dt->mapped = NULL;
> +   munmap(kms_sw_dt->ro_mapped, kms_sw_dt->size);
> +   kms_sw_dt->ro_mapped = NULL;
>  }
>
>  static struct sw_displaytarget *
> --
> 2.16.2.395.g2e18187dfd-goog
>