1 files changed, 99 insertions, 121 deletions

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 56123a6f462e..d362919f4f68 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 #include <linux/mm.h>
 #include <linux/file.h>
@@ -7,6 +8,8 @@
 #include <linux/ptrace.h>
 #include <linux/slab.h>
 #include <linux/seq_file.h>
+#include <linux/sched/mm.h>
+
 #include "internal.h"
 
 /*
@@ -17,15 +20,13 @@
  */
 void task_mem(struct seq_file *m, struct mm_struct *mm)
 {
+	VMA_ITERATOR(vmi, mm, 0);
 	struct vm_area_struct *vma;
 	struct vm_region *region;
-	struct rb_node *p;
 	unsigned long bytes = 0, sbytes = 0, slack = 0, size;
-        
-	down_read(&mm->mmap_sem);
-	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
-		vma = rb_entry(p, struct vm_area_struct, vm_rb);
 
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma) {
 		bytes += kobjsize(vma);
 
 		region = vma->vm_region;
@@ -37,7 +38,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
 		}
 
 		if (atomic_read(&mm->mm_count) > 1 ||
-		    vma->vm_flags & VM_MAYSHARE) {
+		    is_nommu_shared_mapping(vma->vm_flags)) {
 			sbytes += size;
 		} else {
 			bytes += size;
@@ -50,7 +51,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
 		sbytes += kobjsize(mm);
 	else
 		bytes += kobjsize(mm);
-	
+
 	if (current->fs && current->fs->users > 1)
 		sbytes += kobjsize(current->fs);
 	else
@@ -61,34 +62,32 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
 	else
 		bytes += kobjsize(current->files);
 
-	if (current->sighand && atomic_read(&current->sighand->count) > 1)
+	if (current->sighand && refcount_read(&current->sighand->count) > 1)
 		sbytes += kobjsize(current->sighand);
 	else
 		bytes += kobjsize(current->sighand);
 
 	bytes += kobjsize(current); /* includes kernel stack */
 
+	mmap_read_unlock(mm);
+
 	seq_printf(m,
 		"Mem:\t%8lu bytes\n"
 		"Slack:\t%8lu bytes\n"
 		"Shared:\t%8lu bytes\n",
 		bytes, slack, sbytes);
-
-	up_read(&mm->mmap_sem);
 }
 
 unsigned long task_vsize(struct mm_struct *mm)
 {
+	VMA_ITERATOR(vmi, mm, 0);
 	struct vm_area_struct *vma;
-	struct rb_node *p;
 	unsigned long vsize = 0;
 
-	down_read(&mm->mmap_sem);
-	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
-		vma = rb_entry(p, struct vm_area_struct, vm_rb);
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma)
 		vsize += vma->vm_end - vma->vm_start;
-	}
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	return vsize;
 }
 
@@ -96,14 +95,13 @@ unsigned long task_statm(struct mm_struct *mm,
 			 unsigned long *shared, unsigned long *text,
 			 unsigned long *data, unsigned long *resident)
 {
+	VMA_ITERATOR(vmi, mm, 0);
 	struct vm_area_struct *vma;
 	struct vm_region *region;
-	struct rb_node *p;
 	unsigned long size = kobjsize(mm);
 
-	down_read(&mm->mmap_sem);
-	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
-		vma = rb_entry(p, struct vm_area_struct, vm_rb);
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma) {
 		size += kobjsize(vma);
 		region = vma->vm_region;
 		if (region) {
@@ -116,33 +114,23 @@ unsigned long task_statm(struct mm_struct *mm,
 		>> PAGE_SHIFT;
 	*data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
 		>> PAGE_SHIFT;
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	size >>= PAGE_SHIFT;
 	size += *text + *data;
 	*resident = size;
 	return size;
 }
 
-static void pad_len_spaces(struct seq_file *m, int len)
-{
-	len = 25 + sizeof(void*) * 6 - len;
-	if (len < 1)
-		len = 1;
-	seq_printf(m, "%*c", len, ' ');
-}
-
 /*
  * display a single VMA to a sequenced file
  */
-static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
-			  int is_pid)
+static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	struct proc_maps_private *priv = m->private;
 	unsigned long ino = 0;
 	struct file *file;
 	dev_t dev = 0;
-	int flags, len;
+	int flags;
 	unsigned long long pgoff = 0;
 
 	flags = vma->vm_flags;
@@ -155,8 +143,9 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
 		pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
 	}
 
+	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
 	seq_printf(m,
-		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
+		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
 		   vma->vm_start,
 		   vma->vm_end,
 		   flags & VM_READ ? 'r' : '-',
@@ -164,26 +153,14 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
 		   flags & VM_EXEC ? 'x' : '-',
 		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
 		   pgoff,
-		   MAJOR(dev), MINOR(dev), ino, &len);
+		   MAJOR(dev), MINOR(dev), ino);
 
 	if (file) {
-		pad_len_spaces(m, len);
-		seq_path(m, &file->f_path, "");
-	} else if (mm) {
-		pid_t tid = vm_is_stack(priv->task, vma, is_pid);
-
-		if (tid != 0) {
-			pad_len_spaces(m, len);
-			/*
-			 * Thread stack in /proc/PID/task/TID/maps or
-			 * the main process stack.
-			 */
-			if (!is_pid || (vma->vm_start <= mm->start_stack &&
-			    vma->vm_end >= mm->start_stack))
-				seq_printf(m, "[stack]");
-			else
-				seq_printf(m, "[stack:%d]", tid);
-		}
+		seq_pad(m, ' ');
+		seq_path(m, file_user_path(file), "");
+	} else if (mm && vma_is_initial_stack(vma)) {
+		seq_pad(m, ' ');
+		seq_puts(m, "[stack]");
 	}
 
 	seq_putc(m, '\n');
@@ -193,126 +170,127 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
 /*
  * display mapping lines for a particular process's /proc/pid/maps
  */
-static int show_map(struct seq_file *m, void *_p, int is_pid)
+static int show_map(struct seq_file *m, void *_p)
 {
-	struct rb_node *p = _p;
-
-	return nommu_vma_show(m, rb_entry(p, struct vm_area_struct, vm_rb),
-			      is_pid);
+	return nommu_vma_show(m, _p);
 }
 
-static int show_pid_map(struct seq_file *m, void *_p)
+static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
+						loff_t *ppos)
 {
-	return show_map(m, _p, 1);
-}
+	struct vm_area_struct *vma = vma_next(&priv->iter);
 
-static int show_tid_map(struct seq_file *m, void *_p)
-{
-	return show_map(m, _p, 0);
+	if (vma) {
+		*ppos = vma->vm_start;
+	} else {
+		*ppos = -1UL;
+	}
+
+	return vma;
 }
 
-static void *m_start(struct seq_file *m, loff_t *pos)
+static void *m_start(struct seq_file *m, loff_t *ppos)
 {
 	struct proc_maps_private *priv = m->private;
+	unsigned long last_addr = *ppos;
 	struct mm_struct *mm;
-	struct rb_node *p;
-	loff_t n = *pos;
+
+	/* See proc_get_vma(). Zero at the start or after lseek. */
+	if (last_addr == -1UL)
+		return NULL;
 
 	/* pin the task and mm whilst we play with them */
-	priv->task = get_pid_task(priv->pid, PIDTYPE_PID);
+	priv->task = get_proc_task(priv->inode);
 	if (!priv->task)
 		return ERR_PTR(-ESRCH);
 
-	mm = mm_access(priv->task, PTRACE_MODE_READ);
-	if (!mm || IS_ERR(mm)) {
+	mm = priv->lock_ctx.mm;
+	if (!mm || !mmget_not_zero(mm)) {
 		put_task_struct(priv->task);
 		priv->task = NULL;
-		return mm;
+		return NULL;
 	}
-	down_read(&mm->mmap_sem);
 
-	/* start from the Nth VMA */
-	for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
-		if (n-- == 0)
-			return p;
-	return NULL;
+	if (mmap_read_lock_killable(mm)) {
+		mmput(mm);
+		put_task_struct(priv->task);
+		priv->task = NULL;
+		return ERR_PTR(-EINTR);
+	}
+
+	vma_iter_init(&priv->iter, mm, last_addr);
+
+	return proc_get_vma(priv, ppos);
 }
 
-static void m_stop(struct seq_file *m, void *_vml)
+static void m_stop(struct seq_file *m, void *v)
 {
 	struct proc_maps_private *priv = m->private;
+	struct mm_struct *mm = priv->lock_ctx.mm;
 
-	if (priv->task) {
-		struct mm_struct *mm = priv->task->mm;
-		up_read(&mm->mmap_sem);
-		mmput(mm);
-		put_task_struct(priv->task);
-	}
+	if (!priv->task)
+		return;
+
+	mmap_read_unlock(mm);
+	mmput(mm);
+	put_task_struct(priv->task);
+	priv->task = NULL;
 }
 
-static void *m_next(struct seq_file *m, void *_p, loff_t *pos)
+static void *m_next(struct seq_file *m, void *_p, loff_t *ppos)
 {
-	struct rb_node *p = _p;
-
-	(*pos)++;
-	return p ? rb_next(p) : NULL;
+	return proc_get_vma(m->private, ppos);
 }
 
 static const struct seq_operations proc_pid_maps_ops = {
 	.start	= m_start,
 	.next	= m_next,
 	.stop	= m_stop,
-	.show	= show_pid_map
-};
-
-static const struct seq_operations proc_tid_maps_ops = {
-	.start	= m_start,
-	.next	= m_next,
-	.stop	= m_stop,
-	.show	= show_tid_map
+	.show	= show_map
 };
 
 static int maps_open(struct inode *inode, struct file *file,
 		     const struct seq_operations *ops)
 {
 	struct proc_maps_private *priv;
-	int ret = -ENOMEM;
-
-	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
-	if (priv) {
-		priv->pid = proc_pid(inode);
-		ret = seq_open(file, ops);
-		if (!ret) {
-			struct seq_file *m = file->private_data;
-			m->private = priv;
-		} else {
-			kfree(priv);
-		}
+
+	priv = __seq_open_private(file, ops, sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+
+	priv->inode = inode;
+	priv->lock_ctx.mm = proc_mem_open(inode, PTRACE_MODE_READ);
+	if (IS_ERR_OR_NULL(priv->lock_ctx.mm)) {
+		int err = priv->lock_ctx.mm ? PTR_ERR(priv->lock_ctx.mm) : -ESRCH;
+
+		seq_release_private(inode, file);
+		return err;
 	}
-	return ret;
+
+	return 0;
 }
 
-static int pid_maps_open(struct inode *inode, struct file *file)
+
+static int map_release(struct inode *inode, struct file *file)
 {
-	return maps_open(inode, file, &proc_pid_maps_ops);
+	struct seq_file *seq = file->private_data;
+	struct proc_maps_private *priv = seq->private;
+
+	if (priv->lock_ctx.mm)
+		mmdrop(priv->lock_ctx.mm);
+
+	return seq_release_private(inode, file);
 }
 
-static int tid_maps_open(struct inode *inode, struct file *file)
+static int pid_maps_open(struct inode *inode, struct file *file)
 {
-	return maps_open(inode, file, &proc_tid_maps_ops);
+	return maps_open(inode, file, &proc_pid_maps_ops);
 }
 
 const struct file_operations proc_pid_maps_operations = {
 	.open		= pid_maps_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
-	.release	= seq_release_private,
-};
-
-const struct file_operations proc_tid_maps_operations = {
-	.open		= tid_maps_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= seq_release_private,
+	.release	= map_release,
 };