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From: Jan Kara <jack@suse.cz>
To: linux-mm@kvack.org
Cc: linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org,
	Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Jan Kara <jack@suse.cz>
Subject: [PATCH 07/20] mm: Add orig_pte field into vm_fault
Date: Tue, 27 Sep 2016 18:08:11 +0200	[thread overview]
Message-ID: <1474992504-20133-8-git-send-email-jack@suse.cz> (raw)
In-Reply-To: <1474992504-20133-1-git-send-email-jack@suse.cz>

Add orig_pte field to vm_fault structure to allow ->page_mkwrite
handlers to fully handle the fault. This also allows us to save some
passing of extra arguments around.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 include/linux/mm.h |  4 +--
 mm/internal.h      |  2 +-
 mm/khugepaged.c    |  5 ++--
 mm/memory.c        | 76 +++++++++++++++++++++++++++---------------------------
 4 files changed, 44 insertions(+), 43 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5fc6daf5242c..c908fd7243ea 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -300,8 +300,8 @@ struct vm_fault {
 	unsigned long virtual_address;	/* Faulting virtual address masked by
 					 * PAGE_MASK */
 	pmd_t *pmd;			/* Pointer to pmd entry matching
-					 * the 'address'
-					 */
+					 * the 'address' */
+	pte_t orig_pte;			/* Value of PTE at the time of fault */
 
 	struct page *cow_page;		/* Handler may choose to COW */
 	struct page *page;		/* ->fault handlers should return a
diff --git a/mm/internal.h b/mm/internal.h
index cc80060914f6..7c7421da5d63 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -36,7 +36,7 @@
 /* Do not use these with a slab allocator */
 #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
 
-int do_swap_page(struct vm_fault *vmf, pte_t orig_pte);
+int do_swap_page(struct vm_fault *vmf);
 
 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
 		unsigned long floor, unsigned long ceiling);
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index f88b2d3810a7..66bc77f2d1d2 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -890,11 +890,12 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
 	vmf.pte = pte_offset_map(pmd, address);
 	for (; vmf.address < address + HPAGE_PMD_NR*PAGE_SIZE;
 			vmf.pte++, vmf.address += PAGE_SIZE) {
-		pteval = *vmf.pte;
+		vmf.orig_pte = *vmf.pte;
+		pteval = vmf.orig_pte;
 		if (!is_swap_pte(pteval))
 			continue;
 		swapped_in++;
-		ret = do_swap_page(&vmf, pteval);
+		ret = do_swap_page(&vmf);
 
 		/* do_swap_page returns VM_FAULT_RETRY with released mmap_sem */
 		if (ret & VM_FAULT_RETRY) {
diff --git a/mm/memory.c b/mm/memory.c
index 48de8187d7b2..0c8779c23925 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2070,8 +2070,8 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page,
  * case, all we need to do here is to mark the page as writable and update
  * any related book-keeping.
  */
-static inline int wp_page_reuse(struct vm_fault *vmf, pte_t orig_pte,
-			struct page *page, int page_mkwrite, int dirty_shared)
+static inline int wp_page_reuse(struct vm_fault *vmf, struct page *page,
+				int page_mkwrite, int dirty_shared)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
@@ -2084,8 +2084,8 @@ static inline int wp_page_reuse(struct vm_fault *vmf, pte_t orig_pte,
 	if (page)
 		page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1);
 
-	flush_cache_page(vma, vmf->address, pte_pfn(orig_pte));
-	entry = pte_mkyoung(orig_pte);
+	flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
+	entry = pte_mkyoung(vmf->orig_pte);
 	entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 	if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1))
 		update_mmu_cache(vma, vmf->address, vmf->pte);
@@ -2135,8 +2135,7 @@ static inline int wp_page_reuse(struct vm_fault *vmf, pte_t orig_pte,
  *   held to the old page, as well as updating the rmap.
  * - In any case, unlock the PTL and drop the reference we took to the old page.
  */
-static int wp_page_copy(struct vm_fault *vmf, pte_t orig_pte,
-		struct page *old_page)
+static int wp_page_copy(struct vm_fault *vmf, struct page *old_page)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct mm_struct *mm = vma->vm_mm;
@@ -2150,7 +2149,7 @@ static int wp_page_copy(struct vm_fault *vmf, pte_t orig_pte,
 	if (unlikely(anon_vma_prepare(vma)))
 		goto oom;
 
-	if (is_zero_pfn(pte_pfn(orig_pte))) {
+	if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
 		new_page = alloc_zeroed_user_highpage_movable(vma,
 							      vmf->address);
 		if (!new_page)
@@ -2174,7 +2173,7 @@ static int wp_page_copy(struct vm_fault *vmf, pte_t orig_pte,
 	 * Re-check the pte - we dropped the lock
 	 */
 	vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl);
-	if (likely(pte_same(*vmf->pte, orig_pte))) {
+	if (likely(pte_same(*vmf->pte, vmf->orig_pte))) {
 		if (old_page) {
 			if (!PageAnon(old_page)) {
 				dec_mm_counter_fast(mm,
@@ -2184,7 +2183,7 @@ static int wp_page_copy(struct vm_fault *vmf, pte_t orig_pte,
 		} else {
 			inc_mm_counter_fast(mm, MM_ANONPAGES);
 		}
-		flush_cache_page(vma, vmf->address, pte_pfn(orig_pte));
+		flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
 		entry = mk_pte(new_page, vma->vm_page_prot);
 		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 		/*
@@ -2268,7 +2267,7 @@ oom:
  * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED
  * mapping
  */
-static int wp_pfn_shared(struct vm_fault *vmf, pte_t orig_pte)
+static int wp_pfn_shared(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 
@@ -2286,16 +2285,15 @@ static int wp_pfn_shared(struct vm_fault *vmf, pte_t orig_pte)
 		 * We might have raced with another page fault while we
 		 * released the pte_offset_map_lock.
 		 */
-		if (!pte_same(*vmf->pte, orig_pte)) {
+		if (!pte_same(*vmf->pte, vmf->orig_pte)) {
 			pte_unmap_unlock(vmf->pte, vmf->ptl);
 			return 0;
 		}
 	}
-	return wp_page_reuse(vmf, orig_pte, NULL, 0, 0);
+	return wp_page_reuse(vmf, NULL, 0, 0);
 }
 
-static int wp_page_shared(struct vm_fault *vmf, pte_t orig_pte,
-		struct page *old_page)
+static int wp_page_shared(struct vm_fault *vmf, struct page *old_page)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
@@ -2321,7 +2319,7 @@ static int wp_page_shared(struct vm_fault *vmf, pte_t orig_pte,
 		 */
 		vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
 						vmf->address, &vmf->ptl);
-		if (!pte_same(*vmf->pte, orig_pte)) {
+		if (!pte_same(*vmf->pte, vmf->orig_pte)) {
 			unlock_page(old_page);
 			pte_unmap_unlock(vmf->pte, vmf->ptl);
 			put_page(old_page);
@@ -2330,7 +2328,7 @@ static int wp_page_shared(struct vm_fault *vmf, pte_t orig_pte,
 		page_mkwrite = 1;
 	}
 
-	return wp_page_reuse(vmf, orig_pte, old_page, page_mkwrite, 1);
+	return wp_page_reuse(vmf, old_page, page_mkwrite, 1);
 }
 
 /*
@@ -2351,13 +2349,13 @@ static int wp_page_shared(struct vm_fault *vmf, pte_t orig_pte,
  * but allow concurrent faults), with pte both mapped and locked.
  * We return with mmap_sem still held, but pte unmapped and unlocked.
  */
-static int do_wp_page(struct vm_fault *vmf, pte_t orig_pte)
+static int do_wp_page(struct vm_fault *vmf)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct page *old_page;
 
-	old_page = vm_normal_page(vma, vmf->address, orig_pte);
+	old_page = vm_normal_page(vma, vmf->address, vmf->orig_pte);
 	if (!old_page) {
 		/*
 		 * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
@@ -2368,10 +2366,10 @@ static int do_wp_page(struct vm_fault *vmf, pte_t orig_pte)
 		 */
 		if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
 				     (VM_WRITE|VM_SHARED))
-			return wp_pfn_shared(vmf, orig_pte);
+			return wp_pfn_shared(vmf);
 
 		pte_unmap_unlock(vmf->pte, vmf->ptl);
-		return wp_page_copy(vmf, orig_pte, old_page);
+		return wp_page_copy(vmf, old_page);
 	}
 
 	/*
@@ -2386,7 +2384,7 @@ static int do_wp_page(struct vm_fault *vmf, pte_t orig_pte)
 			lock_page(old_page);
 			vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
 					vmf->address, &vmf->ptl);
-			if (!pte_same(*vmf->pte, orig_pte)) {
+			if (!pte_same(*vmf->pte, vmf->orig_pte)) {
 				unlock_page(old_page);
 				pte_unmap_unlock(vmf->pte, vmf->ptl);
 				put_page(old_page);
@@ -2406,12 +2404,12 @@ static int do_wp_page(struct vm_fault *vmf, pte_t orig_pte)
 				page_move_anon_rmap(old_page, vma);
 			}
 			unlock_page(old_page);
-			return wp_page_reuse(vmf, orig_pte, old_page, 0, 0);
+			return wp_page_reuse(vmf, old_page, 0, 0);
 		}
 		unlock_page(old_page);
 	} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
 					(VM_WRITE|VM_SHARED))) {
-		return wp_page_shared(vmf, orig_pte, old_page);
+		return wp_page_shared(vmf, old_page);
 	}
 
 	/*
@@ -2420,7 +2418,7 @@ static int do_wp_page(struct vm_fault *vmf, pte_t orig_pte)
 	get_page(old_page);
 
 	pte_unmap_unlock(vmf->pte, vmf->ptl);
-	return wp_page_copy(vmf, orig_pte, old_page);
+	return wp_page_copy(vmf, old_page);
 }
 
 static void unmap_mapping_range_vma(struct vm_area_struct *vma,
@@ -2508,7 +2506,7 @@ EXPORT_SYMBOL(unmap_mapping_range);
  * We return with the mmap_sem locked or unlocked in the same cases
  * as does filemap_fault().
  */
-int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
+int do_swap_page(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct page *page, *swapcache;
@@ -2519,10 +2517,10 @@ int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
 	int exclusive = 0;
 	int ret = 0;
 
-	if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, orig_pte))
+	if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte))
 		goto out;
 
-	entry = pte_to_swp_entry(orig_pte);
+	entry = pte_to_swp_entry(vmf->orig_pte);
 	if (unlikely(non_swap_entry(entry))) {
 		if (is_migration_entry(entry)) {
 			migration_entry_wait(vma->vm_mm, vmf->pmd,
@@ -2530,7 +2528,7 @@ int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
 		} else if (is_hwpoison_entry(entry)) {
 			ret = VM_FAULT_HWPOISON;
 		} else {
-			print_bad_pte(vma, vmf->address, orig_pte, NULL);
+			print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL);
 			ret = VM_FAULT_SIGBUS;
 		}
 		goto out;
@@ -2547,7 +2545,7 @@ int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
 			 */
 			vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
 					vmf->address, &vmf->ptl);
-			if (likely(pte_same(*vmf->pte, orig_pte)))
+			if (likely(pte_same(*vmf->pte, vmf->orig_pte)))
 				ret = VM_FAULT_OOM;
 			delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 			goto unlock;
@@ -2604,7 +2602,7 @@ int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
 	 */
 	vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
 			&vmf->ptl);
-	if (unlikely(!pte_same(*vmf->pte, orig_pte)))
+	if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte)))
 		goto out_nomap;
 
 	if (unlikely(!PageUptodate(page))) {
@@ -2632,9 +2630,10 @@ int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
 		exclusive = RMAP_EXCLUSIVE;
 	}
 	flush_icache_page(vma, page);
-	if (pte_swp_soft_dirty(orig_pte))
+	if (pte_swp_soft_dirty(vmf->orig_pte))
 		pte = pte_mksoft_dirty(pte);
 	set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
+	vmf->orig_pte = pte;
 	if (page == swapcache) {
 		do_page_add_anon_rmap(page, vma, vmf->address, exclusive);
 		mem_cgroup_commit_charge(page, memcg, true, false);
@@ -2664,7 +2663,7 @@ int do_swap_page(struct vm_fault *vmf, pte_t orig_pte)
 	}
 
 	if (vmf->flags & FAULT_FLAG_WRITE) {
-		ret |= do_wp_page(vmf, pte);
+		ret |= do_wp_page(vmf);
 		if (ret & VM_FAULT_ERROR)
 			ret &= VM_FAULT_ERROR;
 		goto out;
@@ -3326,7 +3325,7 @@ static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
 	return mpol_misplaced(page, vma, addr);
 }
 
-static int do_numa_page(struct vm_fault *vmf, pte_t pte)
+static int do_numa_page(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	struct page *page = NULL;
@@ -3334,6 +3333,7 @@ static int do_numa_page(struct vm_fault *vmf, pte_t pte)
 	int last_cpupid;
 	int target_nid;
 	bool migrated = false;
+	pte_t pte = vmf->orig_pte;
 	bool was_writable = pte_write(pte);
 	int flags = 0;
 
@@ -3484,8 +3484,7 @@ static int handle_pte_fault(struct vm_fault *vmf)
 		 * So now it's safe to run pte_offset_map().
 		 */
 		vmf->pte = pte_offset_map(vmf->pmd, vmf->address);
-
-		entry = *vmf->pte;
+		vmf->orig_pte = *vmf->pte;
 
 		/*
 		 * some architectures can have larger ptes than wordsize,
@@ -3496,6 +3495,7 @@ static int handle_pte_fault(struct vm_fault *vmf)
 		 * ptl lock held. So here a barrier will do.
 		 */
 		barrier();
+		entry = vmf->orig_pte;
 		if (pte_none(entry)) {
 			pte_unmap(vmf->pte);
 			vmf->pte = NULL;
@@ -3510,10 +3510,10 @@ static int handle_pte_fault(struct vm_fault *vmf)
 	}
 
 	if (!pte_present(entry))
-		return do_swap_page(vmf, entry);
+		return do_swap_page(vmf);
 
 	if (pte_protnone(entry) && vma_is_accessible(vmf->vma))
-		return do_numa_page(vmf, entry);
+		return do_numa_page(vmf);
 
 	vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd);
 	spin_lock(vmf->ptl);
@@ -3521,7 +3521,7 @@ static int handle_pte_fault(struct vm_fault *vmf)
 		goto unlock;
 	if (vmf->flags & FAULT_FLAG_WRITE) {
 		if (!pte_write(entry))
-			return do_wp_page(vmf, entry);
+			return do_wp_page(vmf);
 		entry = pte_mkdirty(entry);
 	}
 	entry = pte_mkyoung(entry);
-- 
2.6.6

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  parent reply	other threads:[~2016-09-27 16:08 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-27 16:08 [PATCH 0/20 v3] dax: Clear dirty bits after flushing caches Jan Kara
2016-09-27 16:08 ` [PATCH 01/20] mm: Change type of vmf->virtual_address Jan Kara
2016-09-30  9:07   ` Christoph Hellwig
2016-10-14 18:02   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 02/20] mm: Join struct fault_env and vm_fault Jan Kara
2016-09-30  9:10   ` Christoph Hellwig
2016-10-03  7:43     ` Jan Kara
2016-09-27 16:08 ` [PATCH 03/20] mm: Use pgoff in struct vm_fault instead of passing it separately Jan Kara
2016-10-14 18:42   ` Ross Zwisler
2016-10-17  9:01     ` Jan Kara
2016-09-27 16:08 ` [PATCH 04/20] mm: Use passed vm_fault structure in __do_fault() Jan Kara
2016-10-14 19:05   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 05/20] mm: Trim __do_fault() arguments Jan Kara
2016-10-14 20:31   ` Ross Zwisler
2016-10-17  9:04     ` Jan Kara
2016-09-27 16:08 ` [PATCH 06/20] mm: Use pass vm_fault structure for in wp_pfn_shared() Jan Kara
2016-10-14 21:04   ` Ross Zwisler
2016-09-27 16:08 ` Jan Kara [this message]
2016-10-17 16:45   ` [PATCH 07/20] mm: Add orig_pte field into vm_fault Ross Zwisler
2016-10-18 10:13     ` Jan Kara
2016-09-27 16:08 ` [PATCH 08/20] mm: Allow full handling of COW faults in ->fault handlers Jan Kara
2016-10-17 16:50   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 09/20] mm: Factor out functionality to finish page faults Jan Kara
2016-10-17 17:38   ` Ross Zwisler
2016-10-17 17:40   ` Ross Zwisler
2016-10-18  9:44     ` Jan Kara
2016-09-27 16:08 ` [PATCH 10/20] mm: Move handling of COW faults into DAX code Jan Kara
2016-10-17 19:29   ` Ross Zwisler
2016-10-18 10:32     ` Jan Kara
2016-09-27 16:08 ` [PATCH 11/20] mm: Remove unnecessary vma->vm_ops check Jan Kara
2016-10-17 19:40   ` Ross Zwisler
2016-10-18 10:37     ` Jan Kara
2016-09-27 16:08 ` [PATCH 12/20] mm: Factor out common parts of write fault handling Jan Kara
2016-10-17 22:08   ` Ross Zwisler
2016-10-18 10:50     ` Jan Kara
2016-10-18 17:32       ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 13/20] mm: Pass vm_fault structure into do_page_mkwrite() Jan Kara
2016-10-17 22:29   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 14/20] mm: Use vmf->page during WP faults Jan Kara
2016-10-18 17:56   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 15/20] mm: Move part of wp_page_reuse() into the single call site Jan Kara
2016-10-18 17:59   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 16/20] mm: Provide helper for finishing mkwrite faults Jan Kara
2016-10-18 18:35   ` Ross Zwisler
2016-10-19  7:16     ` Jan Kara
2016-10-19 17:21       ` Ross Zwisler
2016-10-20  8:48         ` Jan Kara
2016-09-27 16:08 ` [PATCH 17/20] mm: Export follow_pte() Jan Kara
2016-10-18 18:37   ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 18/20] dax: Make cache flushing protected by entry lock Jan Kara
2016-10-18 19:20   ` Ross Zwisler
2016-10-19  7:19     ` Jan Kara
2016-10-19 18:25     ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 19/20] dax: Protect PTE modification on WP fault by radix tree " Jan Kara
2016-10-18 19:53   ` Ross Zwisler
2016-10-19  7:25     ` Jan Kara
2016-10-19 17:25       ` Ross Zwisler
2016-09-27 16:08 ` [PATCH 20/20] dax: Clear dirty entry tags on cache flush Jan Kara
2016-10-18 22:12   ` Ross Zwisler
2016-10-19  7:30     ` Jan Kara
2016-10-19 16:38       ` Ross Zwisler
2016-09-30  9:14 ` [PATCH 0/20 v3] dax: Clear dirty bits after flushing caches Christoph Hellwig
2016-10-03  7:59   ` Jan Kara
2016-10-03  8:03     ` Christoph Hellwig
2016-10-03  8:15       ` Jan Kara
2016-10-03  9:32         ` Christoph Hellwig
2016-10-03 11:13           ` Jan Kara
2016-10-13 20:34             ` Ross Zwisler
2016-10-17  8:47               ` Jan Kara
2016-10-17 18:59                 ` Ross Zwisler
2016-10-18  9:49                   ` Jan Kara
  -- strict thread matches above, loose matches on Subject: below --
2016-11-18  9:17 [PATCH 0/20 v5] " Jan Kara
2016-11-18  9:17 ` [PATCH 07/20] mm: Add orig_pte field into vm_fault Jan Kara

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