[PATCH 05/12] mm: Remove remaining uses of PFN_DEV

Alistair Popple
2025-05-29T06:32:47Z

PFN_DEV was used by callers of dax_direct_access() to figure out if the
returned PFN is associated with a page using pfn_t_has_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 <apopple@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
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 | 25 ++-----------------------
mm/memory.c | 4 ++--
7 files changed, 11 insertions(+), 36 deletions(-)

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 7248e54..02d7a21 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -923,8 +923,7 @@ __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 6328c3a..3f2ad5f 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1669,14 +1669,12 @@ 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, PFN_DEV), false);
+ ret = vmf_insert_pfn_pmd(vmf, __pfn_to_pfn_t(pfn, 0), false);
break;
#endif
#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
case PUD_ORDER:
- ret = vmf_insert_pfn_pud(vmf,
- __pfn_to_pfn_t(pfn, PFN_DEV), false);
+ ret = vmf_insert_pfn_pud(vmf, __pfn_to_pfn_t(pfn, 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 46afa12..be8c174 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -8,10 +8,8 @@
* PFN_DEV - pfn is not covered by system memmap by default
*/
#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)
{
@@ -33,7 +31,7 @@ static inline pfn_t phys_to_pfn_t(phys_addr_t addr, u64 flags)

static inline bool pfn_t_has_page(pfn_t pfn)
{
- return (pfn.val & PFN_DEV) == 0;
+ return true;
}

static inline unsigned long pfn_t_to_pfn(pfn_t pfn)
@@ -84,23 +82,4 @@ static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
#endif
#endif

-#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
-static inline bool pfn_t_devmap(pfn_t pfn)
-{
- const u64 flags = PFN_DEV;
-
- return (pfn.val & flags) == flags;
-}
-#else
-static inline bool pfn_t_devmap(pfn_t pfn)
-{
- return false;
-}
-pte_t pte_mkdevmap(pte_t pte);
-pmd_t pmd_mkdevmap(pmd_t pmd);
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
- defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
-pud_t pud_mkdevmap(pud_t pud);
-#endif
-#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
#endif /* _LINUX_PFN_T_H_ */
diff --git a/mm/memory.c b/mm/memory.c
index 1a0c813..7a9aaae 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2512,9 +2512,9 @@ 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);
--
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