Thread (4 messages) flat view 4 messages, 3 authors, 2012-05-10

Re: [PATCH] video/via: Convert to kstrtou8_from_user

From: Alexey Dobriyan <hidden>
Date: 2012-04-16 16:36:30
Also in: kernel-janitors, lkml

On Sun, Apr 15, 2012 at 2:24 AM, Peter Huewe [off-list ref] wrote:
This patch replaces the code for getting an number from a
userspace buffer by a simple call to kstrou8_from_user.
This makes it easier to read and less error prone.
Initialization with 0 is not necessary then.
Also "count < 1" check could be dropped, since empty string will fail
with EINVAL.
Otherwise OK.
quoted hunk ↗ jump to hunk
--- a/drivers/video/via/viafbdev.c
+++ b/drivers/video/via/viafbdev.c
@@ -1276,17 +1276,14 @@ static int viafb_dfph_proc_open(struct inode *inode, struct file *file)
 static ssize_t viafb_dfph_proc_write(struct file *file,
       const char __user *buffer, size_t count, loff_t *pos)
 {
-       char buf[20];
+       int err;
       u8 reg_val = 0;
-       unsigned long length;
       if (count < 1)
               return -EINVAL;
-       length = count > 20 ? 20 : count;
-       if (copy_from_user(&buf[0], buffer, length))
-               return -EFAULT;
-       buf[length - 1] = '\0'; /*Ensure end string */
-       if (kstrtou8(buf, 0, &reg_val) < 0)
-               return -EINVAL;
+       err = kstrtou8_from_user(buffer, count, 0, &reg_val);
+       if (err)
+               return err;
+
       viafb_write_reg_mask(CR97, VIACR, reg_val, 0x0f);
       return count;
 }
@@ -1316,17 +1313,14 @@ static int viafb_dfpl_proc_open(struct inode *inode, struct file *file)
 static ssize_t viafb_dfpl_proc_write(struct file *file,
       const char __user *buffer, size_t count, loff_t *pos)
 {
-       char buf[20];
+       int err;
       u8 reg_val = 0;
-       unsigned long length;
       if (count < 1)
               return -EINVAL;
-       length = count > 20 ? 20 : count;
-       if (copy_from_user(&buf[0], buffer, length))
-               return -EFAULT;
-       buf[length - 1] = '\0'; /*Ensure end string */
-       if (kstrtou8(buf, 0, &reg_val) < 0)
-               return -EINVAL;
+       err = kstrtou8_from_user(buffer, count, 0, &reg_val);
+       if (err)
+               return err;
+
       viafb_write_reg_mask(CR99, VIACR, reg_val, 0x0f);
       return count;
 }
--
1.7.3.4

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