Commit 06f3662c authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/gem-shmem: Refactor drm_gem_shmem_try_map_pmd() 



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: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Link: https://patch.msgid.link/20260227114509.165572-5-tzimmermann@suse.de
parent 5cf8de6c

drivers/gpu/drm/drm_gem_shmem_helper.c

+12 −13
Original line number Diff line number Diff line
@@ -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);
@@ -591,12 +589,13 @@ 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);



	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: