[PATCH 1/2 v2] mfd/ab3550: Convert to kstrtou8_from_user

From: Peter Huewe
Date: Mon Jun 20 2011 - 15:46:46 EST


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.

Since the old buffers held only values up to 255, we don't need
kstrtoul, but rather kstrtou8.

Kernel Version: v3.0-rc3

Changes in v2:
- Use kstrtou8 instead of kstrtoul due to small numbers
- Dropped then unnecessary checks
(Both remarks from Alexey Dobriyan, Thanks!)

Signed-off-by: Peter Huewe <peterhuewe@xxxxxx>
---
drivers/mfd/ab3550-core.c | 63 ++++++++++++--------------------------------
1 files changed, 17 insertions(+), 46 deletions(-)

diff --git a/drivers/mfd/ab3550-core.c b/drivers/mfd/ab3550-core.c
index 3d7dce6..a7370ba 100644
--- a/drivers/mfd/ab3550-core.c
+++ b/drivers/mfd/ab3550-core.c
@@ -879,20 +879,13 @@ static ssize_t ab3550_bank_write(struct file *file,
size_t count, loff_t *ppos)
{
struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
- char buf[32];
- int buf_size;
- unsigned long user_bank;
+ u8 user_bank;
int err;

- /* Get userspace string and assure termination */
- buf_size = min(count, (sizeof(buf) - 1));
- if (copy_from_user(buf, user_buf, buf_size))
- return -EFAULT;
- buf[buf_size] = 0;
-
- err = strict_strtoul(buf, 0, &user_bank);
+ /* Get userspace string and convert to number */
+ err = kstrtou8_from_user(user_buf, count, 0, &user_bank);
if (err)
- return -EINVAL;
+ return err;

if (user_bank >= AB3550_NUM_BANKS) {
dev_err(&ab->i2c_client[0]->dev,
@@ -902,7 +895,7 @@ static ssize_t ab3550_bank_write(struct file *file,

ab->debug_bank = user_bank;

- return buf_size;
+ return count;
}

static int ab3550_address_print(struct seq_file *s, void *p)
@@ -923,27 +916,16 @@ static ssize_t ab3550_address_write(struct file *file,
size_t count, loff_t *ppos)
{
struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
- char buf[32];
- int buf_size;
- unsigned long user_address;
+ u8 user_address;
int err;

- /* Get userspace string and assure termination */
- buf_size = min(count, (sizeof(buf) - 1));
- if (copy_from_user(buf, user_buf, buf_size))
- return -EFAULT;
- buf[buf_size] = 0;
-
- err = strict_strtoul(buf, 0, &user_address);
+ /* Get userspace string and convert to number */
+ err = kstrtou8_from_user(user_buf, count, 0, &user_address);
if (err)
- return -EINVAL;
- if (user_address > 0xff) {
- dev_err(&ab->i2c_client[0]->dev,
- "debugfs error input > 0xff\n");
- return -EINVAL;
- }
+ return err;
+
ab->debug_address = user_address;
- return buf_size;
+ return count;
}

static int ab3550_val_print(struct seq_file *s, void *p)
@@ -971,26 +953,15 @@ static ssize_t ab3550_val_write(struct file *file,
size_t count, loff_t *ppos)
{
struct ab3550 *ab = ((struct seq_file *)(file->private_data))->private;
- char buf[32];
- int buf_size;
- unsigned long user_val;
+ u8 user_val;
int err;
u8 regvalue;

- /* Get userspace string and assure termination */
- buf_size = min(count, (sizeof(buf)-1));
- if (copy_from_user(buf, user_buf, buf_size))
- return -EFAULT;
- buf[buf_size] = 0;
-
- err = strict_strtoul(buf, 0, &user_val);
+ /* Get userspace string and convert to number */
+ err = kstrtou8_from_user(user_buf, count, 0, &user_val);
if (err)
- return -EINVAL;
- if (user_val > 0xff) {
- dev_err(&ab->i2c_client[0]->dev,
- "debugfs error input > 0xff\n");
- return -EINVAL;
- }
+ return err;
+
err = mask_and_set_register_interruptible(
ab, (u8)ab->debug_bank,
(u8)ab->debug_address, 0xFF, (u8)user_val);
@@ -1002,7 +973,7 @@ static ssize_t ab3550_val_write(struct file *file,
if (err)
return -EINVAL;

- return buf_size;
+ return count;
}

static const struct file_operations ab3550_bank_fops = {
--
1.7.3.4

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