[RFC,2/4] mm: Remove uses of PFN_DEV

Commit Message

Alistair Popple Jan. 8, 2025, 1:18 a.m. UTC

PFN_DEV is used by callers of dax_direct_access() to figure out if the
returned PFN is associated with a page or not. However all DAX PFNs
now require an assoicated ZONE_DEVICE page so can assume a page
exists.

Other users of PFN_DEV were setting it before calling
vmf_insert_mixed(). This is unnecessary as it is no longer checked,
instead relying on pfn_valid() to determine if there is an associated
page or not.

Signed-off-by: Alistair Popple <[e-mail]>
---
 drivers/gpu/drm/gma500/fbdev.c     | 2 +-
 drivers/gpu/drm/omapdrm/omap_gem.c | 5 ++---
 drivers/s390/block/dcssblk.c       | 3 +--
 drivers/vfio/pci/vfio_pci_core.c   | 6 ++----
 fs/cramfs/inode.c                  | 2 +-
 include/linux/pfn_t.h              | 4 +---
 mm/memory.c                        | 4 ++--
 7 files changed, 10 insertions(+), 16 deletions(-)

Comments

Christoph Hellwig Jan. 8, 2025, 5:51 a.m. UTC | #1

Looks good:

Reviewed-by: Christoph Hellwig <[e-mail]>

Patch

diff --git a/drivers/gpu/drm/gma500/fbdev.c b/drivers/gpu/drm/gma500/fbdev.c
index 8edefea..109efdc 100644
--- a/drivers/gpu/drm/gma500/fbdev.c
+++ b/drivers/gpu/drm/gma500/fbdev.c
@@ -33,7 +33,7 @@  static vm_fault_t psb_fbdev_vm_fault(struct vm_fault *vmf)
 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
 	for (i = 0; i < page_num; ++i) {
-		err = vmf_insert_mixed(vma, address, __pfn_to_pfn_t(pfn, PFN_DEV));
+		err = vmf_insert_mixed(vma, address, __pfn_to_pfn_t(pfn, 0));
 		if (unlikely(err & VM_FAULT_ERROR))
 			break;
 		address += PAGE_SIZE;
diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
index b9c67e4..9df05b2 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem.c
@@ -371,8 +371,7 @@  static vm_fault_t omap_gem_fault_1d(struct drm_gem_object *obj,
 	VERB("Inserting %p pfn %lx, pa %lx", (void *)vmf->address,
 			pfn, pfn << PAGE_SHIFT);
 
-	return vmf_insert_mixed(vma, vmf->address,
-			__pfn_to_pfn_t(pfn, PFN_DEV));
+	return vmf_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, 0));
 }
 
 /* Special handling for the case of faulting in 2d tiled buffers */
@@ -468,7 +467,7 @@  static vm_fault_t omap_gem_fault_2d(struct drm_gem_object *obj,
 
 	for (i = n; i > 0; i--) {
 		ret = vmf_insert_mixed(vma,
-			vaddr, __pfn_to_pfn_t(pfn, PFN_DEV));
+			vaddr, __pfn_to_pfn_t(pfn, 0));
 		if (ret & VM_FAULT_ERROR)
 			break;
 		pfn += priv->usergart[fmt].stride_pfn;
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 1ffc86e..8a0d590 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -924,8 +924,7 @@  __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff,
 	if (kaddr)
 		*kaddr = __va(dev_info->start + offset);
 	if (pfn)
-		*pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset),
-				      PFN_DEV);
+		*pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), 0);
 
 	return (dev_sz - offset) / PAGE_SIZE;
 }
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 90240c8..e6b6c01 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1680,14 +1680,12 @@  static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
 		break;
 #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
 	case PMD_ORDER:
-		ret = vmf_insert_pfn_pmd(vmf, __pfn_to_pfn_t(pfn + pgoff,
-							     PFN_DEV), false);
+		ret = vmf_insert_pfn_pmd(vmf, __pfn_to_pfn_t(pfn + pgoff, 0), false);
 		break;
 #endif
 #ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
 	case PUD_ORDER:
-		ret = vmf_insert_pfn_pud(vmf, __pfn_to_pfn_t(pfn + pgoff,
-							     PFN_DEV), false);
+		ret = vmf_insert_pfn_pud(vmf, __pfn_to_pfn_t(pfn + pgoff, 0), false);
 		break;
 #endif
 	default:
diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index b84d174..820a664 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -412,7 +412,7 @@  static int cramfs_physmem_mmap(struct file *file, struct vm_area_struct *vma)
 		for (i = 0; i < pages && !ret; i++) {
 			vm_fault_t vmf;
 			unsigned long off = i * PAGE_SIZE;
-			pfn_t pfn = phys_to_pfn_t(address + off, PFN_DEV);
+			pfn_t pfn = phys_to_pfn_t(address + off, 0);
 			vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn);
 			if (vmf & VM_FAULT_ERROR)
 				ret = vm_fault_to_errno(vmf, 0);
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index 75bb77c..034b5b0 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -11,10 +11,8 @@ 
  * PFN_MAP - pfn has a dynamic page mapping established by a device driver
  */
 #define PFN_FLAGS_MASK (((u64) (~PAGE_MASK)) << (BITS_PER_LONG_LONG - PAGE_SHIFT))
-#define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3))
 
-#define PFN_FLAGS_TRACE \
-	{ PFN_DEV,	"DEV" }
+#define PFN_FLAGS_TRACE { }
 
 static inline pfn_t __pfn_to_pfn_t(unsigned long pfn, u64 flags)
 {
diff --git a/mm/memory.c b/mm/memory.c
index e1d647c..5f7a441 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2510,9 +2510,9 @@  vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
 	if (!pfn_modify_allowed(pfn, pgprot))
 		return VM_FAULT_SIGBUS;
 
-	track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV));
+	track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, 0));
 
-	return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot,
+	return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, 0), pgprot,
 			false);
 }
 EXPORT_SYMBOL(vmf_insert_pfn_prot);