linux-kernel - Re: [PATCH v2] gpu: drm: udl: Adding new typedef vm_fault

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Date:   Mon, 21 May 2018 10:27:44 +0530
From:   Souptick Joarder <jrdr.linux@...il.com>
To:     airlied@...hat.com,
        Christian König <christian.koenig@....com>,
        Cihangir Aktürk <cakturk@...il.com>,
        Sean Paul <seanpaul@...omium.org>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Michal Hocko <mhocko@...nel.org>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Matthew Wilcox <willy@...radead.org>
Subject: Re: [PATCH v2] gpu: drm: udl: Adding new typedef vm_fault_t

On Thu, May 10, 2018 at 7:18 PM, Souptick Joarder <jrdr.linux@...il.com> wrote:
> On Wed, Apr 25, 2018 at 10:29 AM, Souptick Joarder <jrdr.linux@...il.com> wrote:
>> Use new return type vm_fault_t for fault and huge_fault
>> handler. For now, this is just documenting that the
>> function returns a VM_FAULT value rather than an errno.
>> Once all instances are converted, vm_fault_t will become
>> a distinct type.
>>
>> Commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>>
>> Previously vm_insert_page() returns err which driver
>> mapped into VM_FAULT_* type. The new function vmf_
>> insert_page() will replace this inefficiency by
>> returning VM_FAULT_* type.
>>
>> Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
>> Reviewed-by: Matthew Wilcox <mawilcox@...rosoft.com>
>> ---
>> v2: Updated the change log
>>
>>  drivers/gpu/drm/udl/udl_drv.h |  3 ++-
>>  drivers/gpu/drm/udl/udl_gem.c | 15 ++-------------
>>  2 files changed, 4 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
>> index 2a75ab8..11151c4 100644
>> --- a/drivers/gpu/drm/udl/udl_drv.h
>> +++ b/drivers/gpu/drm/udl/udl_drv.h
>> @@ -16,6 +16,7 @@
>>
>>  #include <linux/usb.h>
>>  #include <drm/drm_gem.h>
>> +#include <linux/mm_types.h>
>>
>>  #define DRIVER_NAME            "udl"
>>  #define DRIVER_DESC            "DisplayLink"
>> @@ -134,7 +135,7 @@ struct drm_gem_object *udl_gem_prime_import(struct drm_device *dev,
>>  int udl_gem_vmap(struct udl_gem_object *obj);
>>  void udl_gem_vunmap(struct udl_gem_object *obj);
>>  int udl_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
>> -int udl_gem_fault(struct vm_fault *vmf);
>> +vm_fault_t udl_gem_fault(struct vm_fault *vmf);
>>
>>  int udl_handle_damage(struct udl_framebuffer *fb, int x, int y,
>>                       int width, int height);
>> diff --git a/drivers/gpu/drm/udl/udl_gem.c b/drivers/gpu/drm/udl/udl_gem.c
>> index dee6bd9..cf5fe35 100644
>> --- a/drivers/gpu/drm/udl/udl_gem.c
>> +++ b/drivers/gpu/drm/udl/udl_gem.c
>> @@ -100,13 +100,12 @@ int udl_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
>>         return ret;
>>  }
>>
>> -int udl_gem_fault(struct vm_fault *vmf)
>> +vm_fault_t udl_gem_fault(struct vm_fault *vmf)
>>  {
>>         struct vm_area_struct *vma = vmf->vma;
>>         struct udl_gem_object *obj = to_udl_bo(vma->vm_private_data);
>>         struct page *page;
>>         unsigned int page_offset;
>> -       int ret = 0;
>>
>>         page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
>>
>> @@ -114,17 +113,7 @@ int udl_gem_fault(struct vm_fault *vmf)
>>                 return VM_FAULT_SIGBUS;
>>
>>         page = obj->pages[page_offset];
>> -       ret = vm_insert_page(vma, vmf->address, page);
>> -       switch (ret) {
>> -       case -EAGAIN:
>> -       case 0:
>> -       case -ERESTARTSYS:
>> -               return VM_FAULT_NOPAGE;
>> -       case -ENOMEM:
>> -               return VM_FAULT_OOM;
>> -       default:
>> -               return VM_FAULT_SIGBUS;
>> -       }
>> +       return vmf_insert_page(vma, vmf->address, page);
>>  }
>>
>>  int udl_gem_get_pages(struct udl_gem_object *obj)
>> --
>> 1.9.1
>>
>
> Any comment on this patch ?

If no comment, we would like to get this patch in queue
for 4.18.