Re: [PATCH v3] gpu: drm: gma500: Change return type to vm_fault_t

From: Souptick Joarder
Date: Mon Jun 04 2018 - 01:17:36 EST


On Sun, May 27, 2018 at 6:15 AM, Souptick Joarder <jrdr.linux@xxxxxxxxx> wrote:
> Use new return type vm_fault_t for 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.
>
> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>
> Previously vm_insert_{pfn,mixed} returns err which driver
> mapped into VM_FAULT_* type. The new function
> vmf_insert_{pfn,mixed} will replace this inefficiency by
> returning VM_FAULT_* type.
>
> vmf_error() is the newly introduce inline function
> in 4.17-rc6.
>
> Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
> Reviewed-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> ---
> v2: updated the change log
>
> v3: Fixed kbuild error
>
> drivers/gpu/drm/gma500/framebuffer.c | 14 +++++---------
> drivers/gpu/drm/gma500/gem.c | 27 ++++++++++-----------------
> drivers/gpu/drm/gma500/psb_drv.h | 3 ++-
> 3 files changed, 17 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
> index cb0a2ae..632aadb 100644
> --- a/drivers/gpu/drm/gma500/framebuffer.c
> +++ b/drivers/gpu/drm/gma500/framebuffer.c
> @@ -111,7 +111,7 @@ static int psbfb_pan(struct fb_var_screeninfo *var, struct fb_info *info)
> return 0;
> }
>
> -static int psbfb_vm_fault(struct vm_fault *vmf)
> +static vm_fault_t psbfb_vm_fault(struct vm_fault *vmf)
> {
> struct vm_area_struct *vma = vmf->vma;
> struct psb_framebuffer *psbfb = vma->vm_private_data;
> @@ -120,7 +120,7 @@ static int psbfb_vm_fault(struct vm_fault *vmf)
> int page_num;
> int i;
> unsigned long address;
> - int ret;
> + vm_fault_t ret = VM_FAULT_SIGBUS;
> unsigned long pfn;
> unsigned long phys_addr = (unsigned long)dev_priv->stolen_base +
> psbfb->gtt->offset;
> @@ -133,18 +133,14 @@ static int psbfb_vm_fault(struct vm_fault *vmf)
> for (i = 0; i < page_num; i++) {
> pfn = (phys_addr >> PAGE_SHIFT);
>
> - ret = vm_insert_mixed(vma, address,
> + ret = vmf_insert_mixed(vma, address,
> __pfn_to_pfn_t(pfn, PFN_DEV));
> - if (unlikely((ret == -EBUSY) || (ret != 0 && i > 0)))
> + if (unlikely(ret & VM_FAULT_ERROR))
> break;
> - else if (unlikely(ret != 0)) {
> - ret = (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
> - return ret;
> - }
> address += PAGE_SIZE;
> phys_addr += PAGE_SIZE;
> }
> - return VM_FAULT_NOPAGE;
> + return ret;
> }
>
> static void psbfb_vm_open(struct vm_area_struct *vma)
> diff --git a/drivers/gpu/drm/gma500/gem.c b/drivers/gpu/drm/gma500/gem.c
> index 1312397..e7be5c9 100644
> --- a/drivers/gpu/drm/gma500/gem.c
> +++ b/drivers/gpu/drm/gma500/gem.c
> @@ -134,12 +134,13 @@ int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
> * vma->vm_private_data points to the GEM object that is backing this
> * mapping.
> */
> -int psb_gem_fault(struct vm_fault *vmf)
> +vm_fault_t psb_gem_fault(struct vm_fault *vmf)
> {
> struct vm_area_struct *vma = vmf->vma;
> struct drm_gem_object *obj;
> struct gtt_range *r;
> - int ret;
> + int err;
> + vm_fault_t ret;
> unsigned long pfn;
> pgoff_t page_offset;
> struct drm_device *dev;
> @@ -158,9 +159,10 @@ int psb_gem_fault(struct vm_fault *vmf)
> /* For now the mmap pins the object and it stays pinned. As things
> stand that will do us no harm */
> if (r->mmapping == 0) {
> - ret = psb_gtt_pin(r);
> - if (ret < 0) {
> - dev_err(dev->dev, "gma500: pin failed: %d\n", ret);
> + err = psb_gtt_pin(r);
> + if (err < 0) {
> + dev_err(dev->dev, "gma500: pin failed: %d\n", err);
> + ret = vmf_error(err);
> goto fail;
> }
> r->mmapping = 1;
> @@ -175,18 +177,9 @@ int psb_gem_fault(struct vm_fault *vmf)
> pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
> else
> pfn = page_to_pfn(r->pages[page_offset]);
> - ret = vm_insert_pfn(vma, vmf->address, pfn);
> -
> + ret = vmf_insert_pfn(vma, vmf->address, pfn);
> fail:
> mutex_unlock(&dev_priv->mmap_mutex);
> - switch (ret) {
> - case 0:
> - case -ERESTARTSYS:
> - case -EINTR:
> - return VM_FAULT_NOPAGE;
> - case -ENOMEM:
> - return VM_FAULT_OOM;
> - default:
> - return VM_FAULT_SIGBUS;
> - }
> +
> + return ret;
> }
> diff --git a/drivers/gpu/drm/gma500/psb_drv.h b/drivers/gpu/drm/gma500/psb_drv.h
> index e8300f5..93d2f40 100644
> --- a/drivers/gpu/drm/gma500/psb_drv.h
> +++ b/drivers/gpu/drm/gma500/psb_drv.h
> @@ -21,6 +21,7 @@
> #define _PSB_DRV_H_
>
> #include <linux/kref.h>
> +#include <linux/mm_types.h>
>
> #include <drm/drmP.h>
> #include <drm/drm_global.h>
> @@ -749,7 +750,7 @@ extern int psb_gem_get_aperture(struct drm_device *dev, void *data,
> struct drm_file *file);
> extern int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
> struct drm_mode_create_dumb *args);
> -extern int psb_gem_fault(struct vm_fault *vmf);
> +extern vm_fault_t psb_gem_fault(struct vm_fault *vmf);
>
> /* psb_device.c */
> extern const struct psb_ops psb_chip_ops;
> --
> 1.9.1
>

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