Merge linux-3.0.31 from korg into jellybean

Conflicts:
	arch/arm/mm/proc-v7.S
	drivers/base/core.c
	drivers/gpu/drm/i915/i915_gem_execbuffer.c
	drivers/gpu/drm/i915/intel_display.c
	drivers/gpu/drm/i915/intel_lvds.c
	drivers/gpu/drm/radeon/evergreen.c
	drivers/gpu/drm/radeon/r100.c
	drivers/gpu/drm/radeon/radeon_connectors.c
	drivers/gpu/drm/radeon/rs600.c
	drivers/usb/core/hub.c
	drivers/usb/host/xhci-pci.c
	drivers/usb/host/xhci.c
	drivers/usb/serial/qcserial.c
	fs/proc/base.c

Change-Id: Ia98b35db3f8c0bfd95817867d3acb85be8e5e772

1 files changed, 47 insertions, 61 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index ca54a1b..cd2df5a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -211,8 +211,7 @@ static struct mm_struct *mm_access(struct task_struct *task, unsigned int mode)
 
 	mm = get_task_mm(task);
 	if (mm && mm != current->mm &&
-			!ptrace_may_access(task, mode) &&
-			!capable(CAP_SYS_RESOURCE)) {
+			!ptrace_may_access(task, mode)) {
 		mmput(mm);
 		mm = ERR_PTR(-EACCES);
 	}
@@ -782,6 +781,13 @@ static int mem_open(struct inode* inode, struct file* file)
 	if (IS_ERR(mm))
 		return PTR_ERR(mm);
 
+	if (mm) {
+		/* ensure this mm_struct can't be freed */
+		atomic_inc(&mm->mm_count);
+		/* but do not pin its memory */
+		mmput(mm);
+	}
+
 	/* OK to pass negative loff_t, we can catch out-of-range */
 	file->f_mode |= FMODE_UNSIGNED_OFFSET;
 	file->private_data = mm;
@@ -789,57 +795,13 @@ static int mem_open(struct inode* inode, struct file* file)
 	return 0;
 }
 
-static ssize_t mem_read(struct file * file, char __user * buf,
-			size_t count, loff_t *ppos)
+static ssize_t mem_rw(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos, int write)
 {
-	int ret;
-	char *page;
-	unsigned long src = *ppos;
 	struct mm_struct *mm = file->private_data;
-
-	if (!mm)
-		return 0;
-
-	page = (char *)__get_free_page(GFP_TEMPORARY);
-	if (!page)
-		return -ENOMEM;
-
-	ret = 0;
- 
-	while (count > 0) {
-		int this_len, retval;
-
-		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
-		retval = access_remote_vm(mm, src, page, this_len, 0);
-		if (!retval) {
-			if (!ret)
-				ret = -EIO;
-			break;
-		}
-
-		if (copy_to_user(buf, page, retval)) {
-			ret = -EFAULT;
-			break;
-		}
- 
-		ret += retval;
-		src += retval;
-		buf += retval;
-		count -= retval;
-	}
-	*ppos = src;
-
-	free_page((unsigned long) page);
-	return ret;
-}
-
-static ssize_t mem_write(struct file * file, const char __user *buf,
-			 size_t count, loff_t *ppos)
-{
-	int copied;
+	unsigned long addr = *ppos;
+	ssize_t copied;
 	char *page;
-	unsigned long dst = *ppos;
-	struct mm_struct *mm = file->private_data;
 
 	if (!mm)
 		return 0;
@@ -849,31 +811,54 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
 		return -ENOMEM;
 
 	copied = 0;
+	if (!atomic_inc_not_zero(&mm->mm_users))
+		goto free;
+
 	while (count > 0) {
-		int this_len, retval;
+		int this_len = min_t(int, count, PAGE_SIZE);
 
-		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
-		if (copy_from_user(page, buf, this_len)) {
+		if (write && copy_from_user(page, buf, this_len)) {
 			copied = -EFAULT;
 			break;
 		}
-		retval = access_remote_vm(mm, dst, page, this_len, 1);
-		if (!retval) {
+
+		this_len = access_remote_vm(mm, addr, page, this_len, write);
+		if (!this_len) {
 			if (!copied)
 				copied = -EIO;
 			break;
 		}
-		copied += retval;
-		buf += retval;
-		dst += retval;
-		count -= retval;			
+
+		if (!write && copy_to_user(buf, page, this_len)) {
+			copied = -EFAULT;
+			break;
+		}
+
+		buf += this_len;
+		addr += this_len;
+		copied += this_len;
+		count -= this_len;
 	}
-	*ppos = dst;
+	*ppos = addr;
+	mmput(mm);
 
+free:
 	free_page((unsigned long) page);
 	return copied;
 }
 
+static ssize_t mem_read(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	return mem_rw(file, buf, count, ppos, 0);
+}
+
+static ssize_t mem_write(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	return mem_rw(file, (char __user*)buf, count, ppos, 1);
+}
+
 loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 {
 	switch (orig) {
@@ -893,8 +878,9 @@ loff_t mem_lseek(struct file *file, loff_t offset, int orig)
 static int mem_release(struct inode *inode, struct file *file)
 {
 	struct mm_struct *mm = file->private_data;
+	if (mm)
+		mmdrop(mm);
 
-	mmput(mm);
 	return 0;
 }