On Thu, May 31, 2018 at 11:29 PM, Jordan Crouse <jcrouse@xxxxxxxxxxxxxx> wrote:
> 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, This patch is not merged in 4.18-rc-1.
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