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From: Alistair Popple <apopple@nvidia.com>
To: akpm@linux-foundation.org, linux-mm@kvack.org
Cc: Alistair Popple <apopple@nvidia.com>,
	gerald.schaefer@linux.ibm.com, dan.j.williams@intel.com,
	jgg@ziepe.ca, willy@infradead.org, david@redhat.com,
	linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-xfs@vger.kernel.org, jhubbard@nvidia.com, hch@lst.de,
	zhang.lyra@gmail.com, debug@rivosinc.com, bjorn@kernel.org,
	balbirs@nvidia.com
Subject: [PATCH RFC v2 05/12] mm: Remove remaining uses of PFN_DEV
Date: Wed, 19 Feb 2025 16:04:49 +1100	[thread overview]
Message-ID: <32f2dec28a8e9fb5e193989c5c69ea269dc70dce.1739941374.git-series.apopple@nvidia.com> (raw)
In-Reply-To: <cover.95ff0627bc727f2bae44bea4c00ad7a83fbbcfac.1739941374.git-series.apopple@nvidia.com>

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 586e49e..383e034 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1677,14 +1677,12 @@ 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 84447c7..a527c70 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2513,9 +2513,9 @@ 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);
-- 
git-series 0.9.1


  parent reply	other threads:[~2025-02-19  5:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-19  5:04 [PATCH RFC v2 00/12] mm: Remove pXX_devmap page table bit and pfn_t type Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 01/12] mm: Remove PFN_MAP, PFN_SG_CHAIN and PFN_SG_LAST Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 02/12] mm: Convert pXd_devmap checks to vma_is_dax Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 03/12] mm/pagewalk: Skip dax pages in pagewalk Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 04/12] mm: Convert vmf_insert_mixed() from using pte_devmap to pte_special Alistair Popple
2025-02-19  5:04 ` Alistair Popple [this message]
2025-02-19  5:04 ` [PATCH RFC v2 06/12] mm/gup: Remove pXX_devmap usage from get_user_pages() Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 07/12] mm: Remove redundant pXd_devmap calls Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 08/12] mm/khugepaged: Remove redundant pmd_devmap() check Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 09/12] powerpc: Remove checks for devmap pages and PMDs/PUDs Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 10/12] mm: Remove devmap related functions and page table bits Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 11/12] mm: Remove callers of pfn_t functionality Alistair Popple
2025-02-19  5:04 ` [PATCH RFC v2 12/12] mm/memremap: Remove unused devmap_managed_key Alistair Popple

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