Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a027473..9442631 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/mm.h>
+#include <linux/pagewalk.h>
 #include <linux/vmacache.h>
 #include <linux/hugetlb.h>
 #include <linux/huge_mm.h>
@@ -59,7 +59,7 @@
 	SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
 	SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
 	SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
-	SEQ_PUT_DEC(" kB\nVmPin:\t", mm->pinned_vm);
+	SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm));
 	SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
 	SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
 	SEQ_PUT_DEC(" kB\nRssAnon:\t", anon);
@@ -166,7 +166,11 @@
 	if (!mm || !mmget_not_zero(mm))
 		return NULL;
 
-	down_read(&mm->mmap_sem);
+	if (down_read_killable(&mm->mmap_sem)) {
+		mmput(mm);
+		return ERR_PTR(-EINTR);
+	}
+
 	hold_task_mempolicy(priv);
 	priv->tail_vma = get_gate_vma(mm);
 
@@ -413,21 +417,58 @@
 	unsigned long lazyfree;
 	unsigned long anonymous_thp;
 	unsigned long shmem_thp;
+	unsigned long file_thp;
 	unsigned long swap;
 	unsigned long shared_hugetlb;
 	unsigned long private_hugetlb;
 	u64 pss;
+	u64 pss_anon;
+	u64 pss_file;
+	u64 pss_shmem;
 	u64 pss_locked;
 	u64 swap_pss;
 	bool check_shmem_swap;
 };
 
-static void smaps_account(struct mem_size_stats *mss, struct page *page,
-		bool compound, bool young, bool dirty)
+static void smaps_page_accumulate(struct mem_size_stats *mss,
+		struct page *page, unsigned long size, unsigned long pss,
+		bool dirty, bool locked, bool private)
 {
-	int i, nr = compound ? 1 << compound_order(page) : 1;
+	mss->pss += pss;
+
+	if (PageAnon(page))
+		mss->pss_anon += pss;
+	else if (PageSwapBacked(page))
+		mss->pss_shmem += pss;
+	else
+		mss->pss_file += pss;
+
+	if (locked)
+		mss->pss_locked += pss;
+
+	if (dirty || PageDirty(page)) {
+		if (private)
+			mss->private_dirty += size;
+		else
+			mss->shared_dirty += size;
+	} else {
+		if (private)
+			mss->private_clean += size;
+		else
+			mss->shared_clean += size;
+	}
+}
+
+static void smaps_account(struct mem_size_stats *mss, struct page *page,
+		bool compound, bool young, bool dirty, bool locked)
+{
+	int i, nr = compound ? compound_nr(page) : 1;
 	unsigned long size = nr * PAGE_SIZE;
 
+	/*
+	 * First accumulate quantities that depend only on |size| and the type
+	 * of the compound page.
+	 */
 	if (PageAnon(page)) {
 		mss->anonymous += size;
 		if (!PageSwapBacked(page) && !dirty && !PageDirty(page))
@@ -440,35 +481,25 @@
 		mss->referenced += size;
 
 	/*
+	 * Then accumulate quantities that may depend on sharing, or that may
+	 * differ page-by-page.
+	 *
 	 * page_count(page) == 1 guarantees the page is mapped exactly once.
 	 * If any subpage of the compound page mapped with PTE it would elevate
 	 * page_count().
 	 */
 	if (page_count(page) == 1) {
-		if (dirty || PageDirty(page))
-			mss->private_dirty += size;
-		else
-			mss->private_clean += size;
-		mss->pss += (u64)size << PSS_SHIFT;
+		smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty,
+			locked, true);
 		return;
 	}
-
 	for (i = 0; i < nr; i++, page++) {
 		int mapcount = page_mapcount(page);
-
-		if (mapcount >= 2) {
-			if (dirty || PageDirty(page))
-				mss->shared_dirty += PAGE_SIZE;
-			else
-				mss->shared_clean += PAGE_SIZE;
-			mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount;
-		} else {
-			if (dirty || PageDirty(page))
-				mss->private_dirty += PAGE_SIZE;
-			else
-				mss->private_clean += PAGE_SIZE;
-			mss->pss += PAGE_SIZE << PSS_SHIFT;
-		}
+		unsigned long pss = PAGE_SIZE << PSS_SHIFT;
+		if (mapcount >= 2)
+			pss /= mapcount;
+		smaps_page_accumulate(mss, page, PAGE_SIZE, pss, dirty, locked,
+				      mapcount < 2);
 	}
 }
 
@@ -483,13 +514,16 @@
 
 	return 0;
 }
-#endif
+#else
+#define smaps_pte_hole		NULL
+#endif /* CONFIG_SHMEM */
 
 static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 		struct mm_walk *walk)
 {
 	struct mem_size_stats *mss = walk->private;
 	struct vm_area_struct *vma = walk->vma;
+	bool locked = !!(vma->vm_flags & VM_LOCKED);
 	struct page *page = NULL;
 
 	if (pte_present(*pte)) {
@@ -521,7 +555,7 @@
 		if (!page)
 			return;
 
-		if (radix_tree_exceptional_entry(page))
+		if (xa_is_value(page))
 			mss->swap += PAGE_SIZE;
 		else
 			put_page(page);
@@ -532,7 +566,7 @@
 	if (!page)
 		return;
 
-	smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte));
+	smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte), locked);
 }
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -541,6 +575,7 @@
 {
 	struct mem_size_stats *mss = walk->private;
 	struct vm_area_struct *vma = walk->vma;
+	bool locked = !!(vma->vm_flags & VM_LOCKED);
 	struct page *page;
 
 	/* FOLL_DUMP will return -EFAULT on huge zero page */
@@ -554,8 +589,8 @@
 	else if (is_zone_device_page(page))
 		/* pass */;
 	else
-		VM_BUG_ON_PAGE(1, page);
-	smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd));
+		mss->file_thp += HPAGE_PMD_SIZE;
+	smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd), locked);
 }
 #else
 static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
@@ -697,21 +732,24 @@
 	}
 	return 0;
 }
+#else
+#define smaps_hugetlb_range	NULL
 #endif /* HUGETLB_PAGE */
 
+static const struct mm_walk_ops smaps_walk_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+};
+
+static const struct mm_walk_ops smaps_shmem_walk_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+	.pte_hole		= smaps_pte_hole,
+};
+
 static void smap_gather_stats(struct vm_area_struct *vma,
 			     struct mem_size_stats *mss)
 {
-	struct mm_walk smaps_walk = {
-		.pmd_entry = smaps_pte_range,
-#ifdef CONFIG_HUGETLB_PAGE
-		.hugetlb_entry = smaps_hugetlb_range,
-#endif
-		.mm = vma->vm_mm,
-	};
-
-	smaps_walk.private = mss;
-
 #ifdef CONFIG_SHMEM
 	/* In case of smaps_rollup, reset the value from previous vma */
 	mss->check_shmem_swap = false;
@@ -733,25 +771,36 @@
 			mss->swap += shmem_swapped;
 		} else {
 			mss->check_shmem_swap = true;
-			smaps_walk.pte_hole = smaps_pte_hole;
+			walk_page_vma(vma, &smaps_shmem_walk_ops, mss);
+			return;
 		}
 	}
 #endif
-
 	/* mmap_sem is held in m_start */
-	walk_page_vma(vma, &smaps_walk);
-	if (vma->vm_flags & VM_LOCKED)
-		mss->pss_locked += mss->pss;
+	walk_page_vma(vma, &smaps_walk_ops, mss);
 }
 
 #define SEQ_PUT_DEC(str, val) \
 		seq_put_decimal_ull_width(m, str, (val) >> 10, 8)
 
 /* Show the contents common for smaps and smaps_rollup */
-static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss)
+static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
+	bool rollup_mode)
 {
 	SEQ_PUT_DEC("Rss:            ", mss->resident);
 	SEQ_PUT_DEC(" kB\nPss:            ", mss->pss >> PSS_SHIFT);
+	if (rollup_mode) {
+		/*
+		 * These are meaningful only for smaps_rollup, otherwise two of
+		 * them are zero, and the other one is the same as Pss.
+		 */
+		SEQ_PUT_DEC(" kB\nPss_Anon:       ",
+			mss->pss_anon >> PSS_SHIFT);
+		SEQ_PUT_DEC(" kB\nPss_File:       ",
+			mss->pss_file >> PSS_SHIFT);
+		SEQ_PUT_DEC(" kB\nPss_Shmem:      ",
+			mss->pss_shmem >> PSS_SHIFT);
+	}
 	SEQ_PUT_DEC(" kB\nShared_Clean:   ", mss->shared_clean);
 	SEQ_PUT_DEC(" kB\nShared_Dirty:   ", mss->shared_dirty);
 	SEQ_PUT_DEC(" kB\nPrivate_Clean:  ", mss->private_clean);
@@ -761,6 +810,7 @@
 	SEQ_PUT_DEC(" kB\nLazyFree:       ", mss->lazyfree);
 	SEQ_PUT_DEC(" kB\nAnonHugePages:  ", mss->anonymous_thp);
 	SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
+	SEQ_PUT_DEC(" kB\nFilePmdMapped: ", mss->file_thp);
 	SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
 	seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
 				  mss->private_hugetlb >> 10, 7);
@@ -788,7 +838,10 @@
 	SEQ_PUT_DEC(" kB\nMMUPageSize:    ", vma_mmu_pagesize(vma));
 	seq_puts(m, " kB\n");
 
-	__show_smap(m, &mss);
+	__show_smap(m, &mss, false);
+
+	seq_printf(m, "THPeligible:		%d\n",
+		   transparent_hugepage_enabled(vma));
 
 	if (arch_pkeys_enabled())
 		seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
@@ -820,7 +873,10 @@
 
 	memset(&mss, 0, sizeof(mss));
 
-	down_read(&mm->mmap_sem);
+	ret = down_read_killable(&mm->mmap_sem);
+	if (ret)
+		goto out_put_mm;
+
 	hold_task_mempolicy(priv);
 
 	for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
@@ -833,12 +889,13 @@
 	seq_pad(m, ' ');
 	seq_puts(m, "[rollup]\n");
 
-	__show_smap(m, &mss);
+	__show_smap(m, &mss, true);
 
 	release_task_mempolicy(priv);
 	up_read(&mm->mmap_sem);
-	mmput(mm);
 
+out_put_mm:
+	mmput(mm);
 out_put_task:
 	put_task_struct(priv->task);
 	priv->task = NULL;
@@ -940,10 +997,12 @@
 	pte_t ptent = *pte;
 
 	if (pte_present(ptent)) {
-		ptent = ptep_modify_prot_start(vma->vm_mm, addr, pte);
-		ptent = pte_wrprotect(ptent);
+		pte_t old_pte;
+
+		old_pte = ptep_modify_prot_start(vma, addr, pte);
+		ptent = pte_wrprotect(old_pte);
 		ptent = pte_clear_soft_dirty(ptent);
-		ptep_modify_prot_commit(vma->vm_mm, addr, pte, ptent);
+		ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
 	} else if (is_swap_pte(ptent)) {
 		ptent = pte_swp_clear_soft_dirty(ptent);
 		set_pte_at(vma->vm_mm, addr, pte, ptent);
@@ -1067,6 +1126,11 @@
 	return 0;
 }
 
+static const struct mm_walk_ops clear_refs_walk_ops = {
+	.pmd_entry		= clear_refs_pte_range,
+	.test_walk		= clear_refs_test_walk,
+};
+
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
@@ -1096,15 +1160,10 @@
 		return -ESRCH;
 	mm = get_task_mm(task);
 	if (mm) {
+		struct mmu_notifier_range range;
 		struct clear_refs_private cp = {
 			.type = type,
 		};
-		struct mm_walk clear_refs_walk = {
-			.pmd_entry = clear_refs_pte_range,
-			.test_walk = clear_refs_test_walk,
-			.mm = mm,
-			.private = &cp,
-		};
 
 		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
 			if (down_write_killable(&mm->mmap_sem)) {
@@ -1121,7 +1180,10 @@
 			goto out_mm;
 		}
 
-		down_read(&mm->mmap_sem);
+		if (down_read_killable(&mm->mmap_sem)) {
+			count = -EINTR;
+			goto out_mm;
+		}
 		tlb_gather_mmu(&tlb, mm, 0, -1);
 		if (type == CLEAR_REFS_SOFT_DIRTY) {
 			for (vma = mm->mmap; vma; vma = vma->vm_next) {
@@ -1132,6 +1194,24 @@
 					count = -EINTR;
 					goto out_mm;
 				}
+				/*
+				 * Avoid to modify vma->vm_flags
+				 * without locked ops while the
+				 * coredump reads the vm_flags.
+				 */
+				if (!mmget_still_valid(mm)) {
+					/*
+					 * Silently return "count"
+					 * like if get_task_mm()
+					 * failed. FIXME: should this
+					 * function have returned
+					 * -ESRCH if get_task_mm()
+					 * failed like if
+					 * get_proc_task() fails?
+					 */
+					up_write(&mm->mmap_sem);
+					goto out_mm;
+				}
 				for (vma = mm->mmap; vma; vma = vma->vm_next) {
 					vma->vm_flags &= ~VM_SOFTDIRTY;
 					vma_set_page_prot(vma);
@@ -1139,11 +1219,15 @@
 				downgrade_write(&mm->mmap_sem);
 				break;
 			}
-			mmu_notifier_invalidate_range_start(mm, 0, -1);
+
+			mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
+						0, NULL, mm, 0, -1UL);
+			mmu_notifier_invalidate_range_start(&range);
 		}
-		walk_page_range(0, mm->highest_vm_end, &clear_refs_walk);
+		walk_page_range(mm, 0, mm->highest_vm_end, &clear_refs_walk_ops,
+				&cp);
 		if (type == CLEAR_REFS_SOFT_DIRTY)
-			mmu_notifier_invalidate_range_end(mm, 0, -1);
+			mmu_notifier_invalidate_range_end(&range);
 		tlb_finish_mmu(&tlb, 0, -1);
 		up_read(&mm->mmap_sem);
 out_mm:
@@ -1247,7 +1331,7 @@
 		if (pm->show_pfn)
 			frame = pte_pfn(pte);
 		flags |= PM_PRESENT;
-		page = _vm_normal_page(vma, addr, pte, true);
+		page = vm_normal_page(vma, addr, pte);
 		if (pte_soft_dirty(pte))
 			flags |= PM_SOFT_DIRTY;
 	} else if (is_swap_pte(pte)) {
@@ -1413,8 +1497,16 @@
 
 	return err;
 }
+#else
+#define pagemap_hugetlb_range	NULL
 #endif /* HUGETLB_PAGE */
 
+static const struct mm_walk_ops pagemap_ops = {
+	.pmd_entry	= pagemap_pmd_range,
+	.pte_hole	= pagemap_pte_hole,
+	.hugetlb_entry	= pagemap_hugetlb_range,
+};
+
 /*
  * /proc/pid/pagemap - an array mapping virtual pages to pfns
  *
@@ -1446,7 +1538,6 @@
 {
 	struct mm_struct *mm = file->private_data;
 	struct pagemapread pm;
-	struct mm_walk pagemap_walk = {};
 	unsigned long src;
 	unsigned long svpfn;
 	unsigned long start_vaddr;
@@ -1474,14 +1565,6 @@
 	if (!pm.buffer)
 		goto out_mm;
 
-	pagemap_walk.pmd_entry = pagemap_pmd_range;
-	pagemap_walk.pte_hole = pagemap_pte_hole;
-#ifdef CONFIG_HUGETLB_PAGE
-	pagemap_walk.hugetlb_entry = pagemap_hugetlb_range;
-#endif
-	pagemap_walk.mm = mm;
-	pagemap_walk.private = &pm;
-
 	src = *ppos;
 	svpfn = src / PM_ENTRY_BYTES;
 	start_vaddr = svpfn << PAGE_SHIFT;
@@ -1507,8 +1590,10 @@
 		/* overflow ? */
 		if (end < start_vaddr || end > end_vaddr)
 			end = end_vaddr;
-		down_read(&mm->mmap_sem);
-		ret = walk_page_range(start_vaddr, end, &pagemap_walk);
+		ret = down_read_killable(&mm->mmap_sem);
+		if (ret)
+			goto out_free;
+		ret = walk_page_range(mm, start_vaddr, end, &pagemap_ops, &pm);
 		up_read(&mm->mmap_sem);
 		start_vaddr = end;
 
@@ -1720,6 +1805,11 @@
 }
 #endif
 
+static const struct mm_walk_ops show_numa_ops = {
+	.hugetlb_entry = gather_hugetlb_stats,
+	.pmd_entry = gather_pte_stats,
+};
+
 /*
  * Display pages allocated per node and memory policy via /proc.
  */
@@ -1731,12 +1821,6 @@
 	struct numa_maps *md = &numa_priv->md;
 	struct file *file = vma->vm_file;
 	struct mm_struct *mm = vma->vm_mm;
-	struct mm_walk walk = {
-		.hugetlb_entry = gather_hugetlb_stats,
-		.pmd_entry = gather_pte_stats,
-		.private = md,
-		.mm = mm,
-	};
 	struct mempolicy *pol;
 	char buffer[64];
 	int nid;
@@ -1770,7 +1854,7 @@
 		seq_puts(m, " huge");
 
 	/* mmap_sem is held by m_start */
-	walk_page_vma(vma, &walk);
+	walk_page_vma(vma, &show_numa_ops, md);
 
 	if (!md->pages)
 		goto out;