On Mon, May 28, 2018 at 12:38:41PM +0530, Souptick Joarder wrote:
> On Mon, May 21, 2018 at 10:59 PM, 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_mixed() returns err which driver
> > mapped into VM_FAULT_* type. The new function
> > vmf_insert_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>
> > ---
> > drivers/gpu/drm/msm/msm_drv.h | 3 ++-
> > drivers/gpu/drm/msm/msm_gem.c | 33 ++++++++++-----------------------
> > 2 files changed, 12 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
> > index 0a653dd..44b4ca7 100644
> > --- a/drivers/gpu/drm/msm/msm_drv.h
> > +++ b/drivers/gpu/drm/msm/msm_drv.h
> > @@ -33,6 +33,7 @@
> > #include <linux/of_graph.h>
> > #include <linux/of_device.h>
> > #include <asm/sizes.h>
> > +#include <linux/mm_types.h>
> >
> > #include <drm/drmP.h>
> > #include <drm/drm_atomic.h>
> > @@ -188,7 +189,7 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
> > int msm_gem_mmap_obj(struct drm_gem_object *obj,
> > struct vm_area_struct *vma);
> > int msm_gem_mmap(struct file *filp, struct vm_area_struct *vma);
> > -int msm_gem_fault(struct vm_fault *vmf);
> > +vm_fault_t msm_gem_fault(struct vm_fault *vmf);
> > uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj);
> > int msm_gem_get_iova(struct drm_gem_object *obj,
> > struct msm_gem_address_space *aspace, uint64_t *iova);
> > diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> > index 07376de..27a5ab5 100644
> > --- a/drivers/gpu/drm/msm/msm_gem.c
> > +++ b/drivers/gpu/drm/msm/msm_gem.c
> > @@ -217,7 +217,7 @@ int msm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
> > return msm_gem_mmap_obj(vma->vm_private_data, vma);
> > }
> >
> > -int msm_gem_fault(struct vm_fault *vmf)
> > +vm_fault_t msm_gem_fault(struct vm_fault *vmf)
> > {
> > struct vm_area_struct *vma = vmf->vma;
> > struct drm_gem_object *obj = vma->vm_private_data;
> > @@ -225,15 +225,18 @@ int msm_gem_fault(struct vm_fault *vmf)
> > struct page **pages;
> > unsigned long pfn;
> > pgoff_t pgoff;
> > - int ret;
> > + int err;
> > + vm_fault_t ret;
> >
> > /*
> > * vm_ops.open/drm_gem_mmap_obj and close get and put
> > * a reference on obj. So, we dont need to hold one here.
> > */
> > - ret = mutex_lock_interruptible(&msm_obj->lock);
> > - if (ret)
> > + err = mutex_lock_interruptible(&msm_obj->lock);
> > + if (err) {
> > + ret = VM_FAULT_NOPAGE;
> > goto out;
> > + }
> >
> > if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
> > mutex_unlock(&msm_obj->lock);
> > @@ -243,7 +246,7 @@ int msm_gem_fault(struct vm_fault *vmf)
> > /* make sure we have pages attached now */
> > pages = get_pages(obj);
> > if (IS_ERR(pages)) {
> > - ret = PTR_ERR(pages);
> > + ret = vmf_error(PTR_ERR(pages));
> > goto out_unlock;
> > }
> >
> > @@ -255,27 +258,11 @@ int msm_gem_fault(struct vm_fault *vmf)
> > VERB("Inserting %p pfn %lx, pa %lx", (void *)vmf->address,
> > pfn, pfn << PAGE_SHIFT);
> >
> > - ret = vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
> > -
> > + ret = vmf_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
> > out_unlock:
> > mutex_unlock(&msm_obj->lock);
> > out:
> > - switch (ret) {
> > - case -EAGAIN:
> > - case 0:
> > - case -ERESTARTSYS:
> > - case -EINTR:
> > - case -EBUSY:
> > - /*
> > - * EBUSY is ok: this just means that another thread
> > - * already did the job.
> > - */
> > - return VM_FAULT_NOPAGE;
> > - case -ENOMEM:
> > - return VM_FAULT_OOM;
> > - default:
> > - return VM_FAULT_SIGBUS;
> > - }
> > + return ret;
> > }
> >
> > /** get mmap offset */
> > --
> > 1.9.1
> >
>
> Any comment for this patch ?
Sorry for the delay, I wanted to get a chance to test it. It seems to pass the
usual regression tests. LGTM.
Jordan
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