On Mon, 9 Feb 2026 14:27:13 +0100 Thomas Zimmermann <[email protected]> wrote:
> The current mmap page-fault handler requires some changes before it > can track folio access. > > Call to folio_test_pmd_mappable() into the mmap page-fault handler > before calling drm_gem_shmem_try_map_pmd(). The folio will become > useful for tracking the access status. > > Also rename drm_gem_shmem_try_map_pmd() to _try_insert_pfn_pmd() > and only pass the page fault and page-frame number. The new name and > parameters make it similar to vmf_insert_pfn_pmd(). > > No functional changes. If PMD mapping fails or is not supported, > insert a regular PFN as before. > > Signed-off-by: Thomas Zimmermann <[email protected]> Reviewed-by: Boris Brezillon <[email protected]> > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 25 ++++++++++++------------- > 1 file changed, 12 insertions(+), 13 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c > b/drivers/gpu/drm/drm_gem_shmem_helper.c > index ab8e331005f9..c3a054899ba3 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -550,17 +550,14 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, > struct drm_device *dev, > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create); > > -static vm_fault_t drm_gem_shmem_try_map_pmd(struct vm_fault *vmf, unsigned > long addr, > - struct page *page) > +static vm_fault_t drm_gem_shmem_try_insert_pfn_pmd(struct vm_fault *vmf, > unsigned long pfn) > { > #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP > - unsigned long pfn = page_to_pfn(page); > unsigned long paddr = pfn << PAGE_SHIFT; > - bool aligned = (addr & ~PMD_MASK) == (paddr & ~PMD_MASK); > + bool aligned = (vmf->address & ~PMD_MASK) == (paddr & ~PMD_MASK); > > - if (aligned && > - pmd_none(*vmf->pmd) && > - folio_test_pmd_mappable(page_folio(page))) { > + if (aligned && pmd_none(*vmf->pmd)) { > + /* Read-only mapping; split upon write fault */ > pfn &= PMD_MASK >> PAGE_SHIFT; > return vmf_insert_pfn_pmd(vmf, pfn, false); > } > @@ -580,6 +577,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault > *vmf) > struct page **pages = shmem->pages; > pgoff_t page_offset = vmf->pgoff - vma->vm_pgoff; /* page offset within > VMA */ > struct page *page; > + struct folio *folio; > unsigned long pfn; > > dma_resv_lock(obj->resv, NULL); > @@ -591,15 +589,16 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault > *vmf) > page = pages[page_offset]; > if (drm_WARN_ON_ONCE(dev, !page)) > goto out; > - > - ret = drm_gem_shmem_try_map_pmd(vmf, vmf->address, page); > - if (ret == VM_FAULT_NOPAGE) > - goto out; > + folio = page_folio(page); > > pfn = page_to_pfn(page); > - ret = vmf_insert_pfn(vma, vmf->address, pfn); > > - out: > + if (folio_test_pmd_mappable(folio)) > + ret = drm_gem_shmem_try_insert_pfn_pmd(vmf, pfn); > + if (ret != VM_FAULT_NOPAGE) > + ret = vmf_insert_pfn(vma, vmf->address, pfn); > + > +out: > dma_resv_unlock(obj->resv); > > return ret;
