linux-kernel - [PATCH v2 3/9] mm: remove VM_FAULT

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Message-Id: <20221021101141.84170-4-david@redhat.com>
Date:   Fri, 21 Oct 2022 12:11:35 +0200
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     linux-mm@...ck.org, David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Shuah Khan <shuah@...nel.org>, Hugh Dickins <hughd@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>, Peter Xu <peterx@...hat.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Jason Gunthorpe <jgg@...dia.com>,
        John Hubbard <jhubbard@...dia.com>
Subject: [PATCH v2 3/9] mm: remove VM_FAULT_WRITE

All users -- GUP and KSM -- are gone, let's just remove it.

Acked-by: Peter Xu <peterx@...hat.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 include/linux/mm_types.h | 3 ---
 mm/huge_memory.c         | 2 +-
 mm/memory.c              | 9 ++++-----
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 500e536796ca..6bc3baced3e3 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -847,7 +847,6 @@ typedef __bitwise unsigned int vm_fault_t;
  * @VM_FAULT_OOM:		Out Of Memory
  * @VM_FAULT_SIGBUS:		Bad access
  * @VM_FAULT_MAJOR:		Page read from storage
- * @VM_FAULT_WRITE:		Special case for get_user_pages
  * @VM_FAULT_HWPOISON:		Hit poisoned small page
  * @VM_FAULT_HWPOISON_LARGE:	Hit poisoned large page. Index encoded
  *				in upper bits
@@ -868,7 +867,6 @@ enum vm_fault_reason {
 	VM_FAULT_OOM            = (__force vm_fault_t)0x000001,
 	VM_FAULT_SIGBUS         = (__force vm_fault_t)0x000002,
 	VM_FAULT_MAJOR          = (__force vm_fault_t)0x000004,
-	VM_FAULT_WRITE          = (__force vm_fault_t)0x000008,
 	VM_FAULT_HWPOISON       = (__force vm_fault_t)0x000010,
 	VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020,
 	VM_FAULT_SIGSEGV        = (__force vm_fault_t)0x000040,
@@ -894,7 +892,6 @@ enum vm_fault_reason {
 	{ VM_FAULT_OOM,                 "OOM" },	\
 	{ VM_FAULT_SIGBUS,              "SIGBUS" },	\
 	{ VM_FAULT_MAJOR,               "MAJOR" },	\
-	{ VM_FAULT_WRITE,               "WRITE" },	\
 	{ VM_FAULT_HWPOISON,            "HWPOISON" },	\
 	{ VM_FAULT_HWPOISON_LARGE,      "HWPOISON_LARGE" },	\
 	{ VM_FAULT_SIGSEGV,             "SIGSEGV" },	\
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1cc4a5f4791e..be13fe55b798 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1379,7 +1379,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf)
 		if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1))
 			update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
 		spin_unlock(vmf->ptl);
-		return VM_FAULT_WRITE;
+		return 0;
 	}
 
 unlock_fallback:
diff --git a/mm/memory.c b/mm/memory.c
index f88c351aecd4..8e72f703ed99 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3242,7 +3242,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 	}
 
 	delayacct_wpcopy_end();
-	return (page_copied && !unshare) ? VM_FAULT_WRITE : 0;
+	return 0;
 oom_free_new:
 	put_page(new_page);
 oom:
@@ -3306,14 +3306,14 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
 		return finish_mkwrite_fault(vmf);
 	}
 	wp_page_reuse(vmf);
-	return VM_FAULT_WRITE;
+	return 0;
 }
 
 static vm_fault_t wp_page_shared(struct vm_fault *vmf)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
-	vm_fault_t ret = VM_FAULT_WRITE;
+	vm_fault_t ret = 0;
 
 	get_page(vmf->page);
 
@@ -3464,7 +3464,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf)
 			return 0;
 		}
 		wp_page_reuse(vmf);
-		return VM_FAULT_WRITE;
+		return 0;
 	} else if (unshare) {
 		/* No anonymous page -> nothing to do. */
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
@@ -3983,7 +3983,6 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 		if (vmf->flags & FAULT_FLAG_WRITE) {
 			pte = maybe_mkwrite(pte_mkdirty(pte), vma);
 			vmf->flags &= ~FAULT_FLAG_WRITE;
-			ret |= VM_FAULT_WRITE;
 		}
 		rmap_flags |= RMAP_EXCLUSIVE;
 	}
-- 
2.37.3