sysfs: fix error handling in binattr write()

Error handling in fs/sysfs/bin.c:write() was wrong because size_t
count is used to receive return value from flush_write() which is
negative on failure.

This patch updates write() such that int variable is used instead.
read() is updated the same way for consistency.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 14 deletions

diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index d3b9f5f07db1..606267a36275 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -33,16 +33,13 @@ fill_read(struct dentry *dentry, char *buffer, loff_t off, size_t count)
 }
 
 static ssize_t
-read(struct file * file, char __user * userbuf, size_t count, loff_t * off)
+read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off)
 {
         char *buffer = file->private_data;
         struct dentry *dentry = file->f_path.dentry;
         int size = dentry->d_inode->i_size;
         loff_t offs = *off;
-        int ret;
-
-        if (count > PAGE_SIZE)
-                count = PAGE_SIZE;
+        int count = min_t(size_t, bytes, PAGE_SIZE);
 
         if (size) {
                 if (offs > size)
@@ -51,15 +48,14 @@ read(struct file * file, char __user * userbuf, size_t count, loff_t * off)
                         count = size - offs;
         }
 
-        ret = fill_read(dentry, buffer, offs, count);
-        if (ret < 0) 
-                return ret;
-        count = ret;
+        count = fill_read(dentry, buffer, offs, count);
+        if (count < 0)
+                return count;
 
         if (copy_to_user(userbuf, buffer, count))
                 return -EFAULT;
 
-        pr_debug("offs = %lld, *off = %lld, count = %zd\n", offs, *off, count);
+        pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
 
         *off = offs + count;
 
@@ -78,16 +74,15 @@ flush_write(struct dentry *dentry, char *buffer, loff_t offset, size_t count)
         return attr->write(kobj, buffer, offset, count);
 }
 
-static ssize_t write(struct file * file, const char __user * userbuf,
-                     size_t count, loff_t * off)
+static ssize_t write(struct file *file, const char __user *userbuf,
+                     size_t bytes, loff_t *off)
 {
         char *buffer = file->private_data;
         struct dentry *dentry = file->f_path.dentry;
         int size = dentry->d_inode->i_size;
         loff_t offs = *off;
+        int count = min_t(size_t, bytes, PAGE_SIZE);
 
-        if (count > PAGE_SIZE)
-                count = PAGE_SIZE;
         if (size) {
                 if (offs > size)
                         return 0;