[PATCH 1/2] mfd/ab3550: Use kstrtoul_from_user

[PATCH 1/2] mfd/ab3550: Use kstrtoul_from_user

[Peter Huewe]

This patch replaces the code for getting an unsigned long from a
userspace buffer by a simple call to kstroul_from_user.
This makes it easier to read and less error prone.

Kernel Version: v3.0-rc2

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/mfd/ab3550-core.c |   41 +++++++++++------------------------------
 1 files changed, 11 insertions(+), 30 deletions(-)

diff --git a/drivers/mfd/ab3550-core.c b/drivers/mfd/ab3550-core.c
index 3d7dce6..56ba194 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;
 	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);
+	err = kstrtoul_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 +916,21 @@ 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;
 	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);
+	err = kstrtoul_from_user(user_buf, count, 0, &user_address);
 	if (err)
-		return -EINVAL;
+		return err;
+
 	if (user_address > 0xff) {
 		dev_err(&ab->i2c_client[0]->dev,
 			"debugfs error input > 0xff\n");
 		return -EINVAL;
 	}
 	ab->debug_address = user_address;
-	return buf_size;
+	return count;
 }
 
 static int ab3550_val_print(struct seq_file *s, void *p)
@@ -971,21 +958,15 @@ 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;
 	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);
+	err = kstrtoul_from_user(user_buf, count, 0, &user_val);
 	if (err)
-		return -EINVAL;
+		return err;
+
 	if (user_val > 0xff) {
 		dev_err(&ab->i2c_client[0]->dev,
 			"debugfs error input > 0xff\n");
@@ -1002,7 +983,7 @@ 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

[PATCH 2/2] mfd/ab8500: Use kstrtoul_from_user

[Peter Huewe]

This patch replaces the code for getting an unsigned long from a
userspace buffer by a simple call to kstroul_from_user.
This makes it easier to read and less error prone.

Kernel Version: v3.0-rc2

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/mfd/ab8500-debugfs.c |   41 +++++++++++------------------------------
 1 files changed, 11 insertions(+), 30 deletions(-)

diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index 64748e4..64bdeeb 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -419,20 +419,13 @@ static ssize_t ab8500_bank_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
 	unsigned long 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);
+	err = kstrtoul_from_user(user_buf, count, 0, &user_bank);
 	if (err)
-		return -EINVAL;
+		return err;
 
 	if (user_bank >= AB8500_NUM_BANKS) {
 		dev_err(dev, "debugfs error input > number of banks\n");
@@ -441,7 +434,7 @@ static ssize_t ab8500_bank_write(struct file *file,
 
 	debug_bank = user_bank;
 
-	return buf_size;
+	return count;
 }
 
 static int ab8500_address_print(struct seq_file *s, void *p)
@@ -459,26 +452,20 @@ static ssize_t ab8500_address_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
 	unsigned long 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);
+	err = kstrtoul_from_user(user_buf, count, 0, &user_address);
 	if (err)
-		return -EINVAL;
+		return err;
+
 	if (user_address > 0xff) {
 		dev_err(dev, "debugfs error input > 0xff\n");
 		return -EINVAL;
 	}
 	debug_address = user_address;
-	return buf_size;
+	return count;
 }
 
 static int ab8500_val_print(struct seq_file *s, void *p)
@@ -509,20 +496,14 @@ static ssize_t ab8500_val_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
 	unsigned long user_val;
 	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_val);
+	err = kstrtoul_from_user(user_buf, count, 0, &user_val);
 	if (err)
-		return -EINVAL;
+		return err;
+
 	if (user_val > 0xff) {
 		dev_err(dev, "debugfs error input > 0xff\n");
 		return -EINVAL;
@@ -534,7 +515,7 @@ static ssize_t ab8500_val_write(struct file *file,
 		return -EINVAL;
 	}
 
-	return buf_size;
+	return count;
 }
 
 static const struct file_operations ab8500_bank_fops = {
-- 
1.7.3.4

[PATCH 1/2] mfd/ab3550: Use kstrtoul_from_user

[Samuel Ortiz]

Hi Peter,

On Mon, Jun 06, 2011 at 10:43:31PM +0200, Peter Huewe wrote:
> This patch replaces the code for getting an unsigned long from a
> userspace buffer by a simple call to kstroul_from_user.
> This makes it easier to read and less error prone.
Thanks, both patches applied.

Cheers,
Samuel.

-- 
Intel Open Source Technology Centre
http://oss.intel.com/

[PATCH 2/2] mfd/ab8500: Use kstrtoul_from_user

[Alexey Dobriyan]

NAK
You should use kstrtou8_from_user() and drop 0xff check as well.

Do NOT blindly replace strict_strtoul with kstrtoul.

On Mon, Jun 6, 2011 at 11:43 PM, Peter Huewe <peterhuewe@gmx.de> wrote:
> - ? ? ? err = strict_strtoul(buf, 0, &user_val);
> + ? ? ? err = kstrtoul_from_user(user_buf, count, 0, &user_val);
> ? ? ? ?if (err)
> - ? ? ? ? ? ? ? return -EINVAL;
> + ? ? ? ? ? ? ? return err;
> +
> ? ? ? ?if (user_val > 0xff) {
> ? ? ? ? ? ? ? ?dev_err(dev, "debugfs error input > 0xff\n");
> ? ? ? ? ? ? ? ?return -EINVAL;

[PATCH 2/2] mfd/ab8500: Use kstrtoul_from_user

[Peter Hüwe]

Am Montag 20 Juni 2011, 15:45:46 schrieb Alexey Dobriyan:
> NAK
> You should use kstrtou8_from_user() and drop 0xff check as well.
> 
> Do NOT blindly replace strict_strtoul with kstrtoul.

Thanks for spotting this - I'll review my other patches as well and redo them.
Sorry for any inconvenience.

Thanks,
Peter

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

[Peter Huewe]

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@gmx.de>
---
 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

[PATCH 2/2 v2] mfd/ab8500: Convert to kstrtou8_from_user

[Peter Huewe]

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.

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@gmx.de>
---
 drivers/mfd/ab8500-debugfs.c |   61 +++++++++++------------------------------
 1 files changed, 17 insertions(+), 44 deletions(-)

diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index 64748e4..7304919 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -419,20 +419,13 @@ static ssize_t ab8500_bank_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((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 >= AB8500_NUM_BANKS) {
 		dev_err(dev, "debugfs error input > number of banks\n");
@@ -441,7 +434,7 @@ static ssize_t ab8500_bank_write(struct file *file,
 
 	debug_bank = user_bank;
 
-	return buf_size;
+	return count;
 }
 
 static int ab8500_address_print(struct seq_file *s, void *p)
@@ -459,26 +452,16 @@ static ssize_t ab8500_address_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((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(dev, "debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
+		return err;
+
 	debug_address = user_address;
-	return buf_size;
+	return count;
 }
 
 static int ab8500_val_print(struct seq_file *s, void *p)
@@ -509,24 +492,14 @@ static ssize_t ab8500_val_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
-	unsigned long user_val;
+	u8 user_val;
 	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_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(dev, "debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
+		return err;
+
 	err = abx500_set_register_interruptible(dev,
 		(u8)debug_bank, debug_address, (u8)user_val);
 	if (err < 0) {
@@ -534,7 +507,7 @@ static ssize_t ab8500_val_write(struct file *file,
 		return -EINVAL;
 	}
 
-	return buf_size;
+	return count;
 }
 
 static const struct file_operations ab8500_bank_fops = {
-- 
1.7.3.4

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

[Alexey Dobriyan]

On Mon, Jun 20, 2011 at 09:46:28PM +0200, Peter Huewe wrote:
> @@ -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;

You don't need temporary variable and should write straight to final location,
because kstrto* functions will never write to result unless it was converted
successfully.

[PATCH v3] mfd/ab8500: Convert to kstrtou8_from_user

[Peter Huewe]

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.

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!)
Changes in v3:
The local struct dev variable isn't needed anymore

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/mfd/ab8500-debugfs.c |   62 +++++++++++------------------------------
 1 files changed, 17 insertions(+), 45 deletions(-)

diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index 64748e4..bb78f4a 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -419,20 +419,13 @@ static ssize_t ab8500_bank_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((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 >= AB8500_NUM_BANKS) {
 		dev_err(dev, "debugfs error input > number of banks\n");
@@ -441,7 +434,7 @@ static ssize_t ab8500_bank_write(struct file *file,
 
 	debug_bank = user_bank;
 
-	return buf_size;
+	return count;
 }
 
 static int ab8500_address_print(struct seq_file *s, void *p)
@@ -458,27 +451,16 @@ static ssize_t ab8500_address_write(struct file *file,
 	const char __user *user_buf,
 	size_t count, loff_t *ppos)
 {
-	struct device *dev = ((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(dev, "debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
+		return err;
+
 	debug_address = user_address;
-	return buf_size;
+	return count;
 }
 
 static int ab8500_val_print(struct seq_file *s, void *p)
@@ -509,24 +491,14 @@ static ssize_t ab8500_val_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
-	unsigned long user_val;
+	u8 user_val;
 	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_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(dev, "debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
+		return err;
+
 	err = abx500_set_register_interruptible(dev,
 		(u8)debug_bank, debug_address, (u8)user_val);
 	if (err < 0) {
@@ -534,7 +506,7 @@ static ssize_t ab8500_val_write(struct file *file,
 		return -EINVAL;
 	}
 
-	return buf_size;
+	return count;
 }
 
 static const struct file_operations ab8500_bank_fops = {
-- 
1.7.3.4

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

[Peter Hüwe]

Am Montag 20 Juni 2011, 21:50:38 schrieb Alexey Dobriyan:
> On Mon, Jun 20, 2011 at 09:46:28PM +0200, Peter Huewe wrote:
> > -	char buf[32];
> > -	int buf_size;
> > -	unsigned long user_address;
> > +	u8 user_address;

> > +	/* Get userspace string and convert to number */
> > +	err = kstrtou8_from_user(user_buf, count, 0, &user_address);
...
> > 
> >  	ab->debug_address = user_address;

> 
> You don't need temporary variable and should write straight to final
> location, because kstrto* functions will never write to result unless it
> was converted successfully.

Alexey thank you very much for your review, hints and most of all patience ;)
The code really gets cleaner and cleaner.

While changing the code (once again ;) and looking at your remarks I also saw 
that ab3550->debug_address and ->debug_bank are always casted to u8.

Do you think I could also change the two fields of the struct ab3550 (only 
used in this file) to u8 in this patch, too?
This way I could get rid of the u8* cast which is now needed in this case, if 
I take you last remark into account.
> err = kstrtou8_from_user(user_buf, count, 0, (u8 *)&ab->debug_address);

And also clean the code from all the other unnecessary u8 casts.

What do you think?
Or split it up into two seperate patches?

Thanks,
Peter

[PATCH 1/2 v3] mfd/ab3550: Convert to kstrtou8_from_user

[Peter Huewe]

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
Changes in v3:
- Drop now unnecessary local variables
- Change the debug_address and debug_bank members to u8 since they hold
  only values up to 255, and also remove the now superfluous u8 casts
(Remarks from Alexey Dobriyan, Thanks!)

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/mfd/ab3550-core.c |   79 +++++++++++++-------------------------------
 1 files changed, 24 insertions(+), 55 deletions(-)

diff --git a/drivers/mfd/ab3550-core.c b/drivers/mfd/ab3550-core.c
index 3d7dce6..bd0df90 100644
--- a/drivers/mfd/ab3550-core.c
+++ b/drivers/mfd/ab3550-core.c
@@ -73,8 +73,8 @@ struct ab3550 {
 	u8 startup_events[AB3550_NUM_EVENT_REG];
 	bool startup_events_read;
 #ifdef CONFIG_DEBUG_FS
-	unsigned int debug_bank;
-	unsigned int debug_address;
+	u8 debug_bank;
+	u8 debug_address;
 #endif
 };
 
@@ -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 +916,14 @@ 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;
 	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, &ab->debug_address);
 	if (err)
-		return -EINVAL;
-	if (user_address > 0xff) {
-		dev_err(&ab->i2c_client[0]->dev,
-			"debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
-	ab->debug_address = user_address;
-	return buf_size;
+		return err;
+
+	return count;
 }
 
 static int ab3550_val_print(struct seq_file *s, void *p)
@@ -952,8 +932,8 @@ static int ab3550_val_print(struct seq_file *s, void *p)
 	int err;
 	u8 regvalue;
 
-	err = get_register_interruptible(ab, (u8)ab->debug_bank,
-		(u8)ab->debug_address, &regvalue);
+	err = get_register_interruptible(ab, ab->debug_bank,
+		ab->debug_address, &regvalue);
 	if (err)
 		return -EINVAL;
 	seq_printf(s, "0x%02X\n", regvalue);
@@ -971,38 +951,27 @@ 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);
+		ab, ab->debug_bank,
+		ab->debug_address, 0xFF, user_val);
 	if (err)
 		return -EINVAL;
 
-	get_register_interruptible(ab, (u8)ab->debug_bank,
-		(u8)ab->debug_address, &regvalue);
+	get_register_interruptible(ab, ab->debug_bank,
+		ab->debug_address, &regvalue);
 	if (err)
 		return -EINVAL;
 
-	return buf_size;
+	return count;
 }
 
 static const struct file_operations ab3550_bank_fops = {
-- 
1.7.3.4

[PATCH 2/2 v4] mfd/ab8500: Convert to kstrtou8_from_user

[Peter Huewe]

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
Changes in v3:
- The local struct dev variable isn't needed anymore
Changes in v4:
- Drop unneccesary now local variables and casts
- Change the debug_address and debug_bank members to u8 since they hold
only values up to 255, and also remove the now superfluous u8 casts

(Remarks from Alexey Dobriyan, Thanks!)

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
---
 drivers/mfd/ab8500-debugfs.c |   74 ++++++++++++-----------------------------
 1 files changed, 22 insertions(+), 52 deletions(-)

diff --git a/drivers/mfd/ab8500-debugfs.c b/drivers/mfd/ab8500-debugfs.c
index 64748e4..5d3cd35 100644
--- a/drivers/mfd/ab8500-debugfs.c
+++ b/drivers/mfd/ab8500-debugfs.c
@@ -14,8 +14,8 @@
 #include <linux/mfd/abx500.h>
 #include <linux/mfd/ab8500.h>
 
-static u32 debug_bank;
-static u32 debug_address;
+static u8 debug_bank;
+static u8 debug_address;
 
 /**
  * struct ab8500_reg_range
@@ -357,7 +357,7 @@ static int ab8500_registers_print(struct seq_file *s, void *p)
 {
 	struct device *dev = s->private;
 	unsigned int i;
-	u32 bank = debug_bank;
+	u8 bank = debug_bank;
 
 	seq_printf(s, AB8500_NAME_STRING " register values:\n");
 
@@ -372,7 +372,7 @@ static int ab8500_registers_print(struct seq_file *s, void *p)
 			int err;
 
 			err = abx500_get_register_interruptible(dev,
-				(u8)bank, (u8)reg, &value);
+				bank, (u8)reg, &value);
 			if (err < 0) {
 				dev_err(dev, "ab->read fail %d\n", err);
 				return err;
@@ -419,20 +419,13 @@ static ssize_t ab8500_bank_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((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 >= AB8500_NUM_BANKS) {
 		dev_err(dev, "debugfs error input > number of banks\n");
@@ -441,7 +434,7 @@ static ssize_t ab8500_bank_write(struct file *file,
 
 	debug_bank = user_bank;
 
-	return buf_size;
+	return count;
 }
 
 static int ab8500_address_print(struct seq_file *s, void *p)
@@ -458,27 +451,14 @@ static ssize_t ab8500_address_write(struct file *file,
 	const char __user *user_buf,
 	size_t count, loff_t *ppos)
 {
-	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
-	unsigned long 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, &debug_address);
 	if (err)
-		return -EINVAL;
-	if (user_address > 0xff) {
-		dev_err(dev, "debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
-	debug_address = user_address;
-	return buf_size;
+		return err;
+
+	return count;
 }
 
 static int ab8500_val_print(struct seq_file *s, void *p)
@@ -488,7 +468,7 @@ static int ab8500_val_print(struct seq_file *s, void *p)
 	u8 regvalue;
 
 	ret = abx500_get_register_interruptible(dev,
-		(u8)debug_bank, (u8)debug_address, &regvalue);
+		debug_bank, debug_address, &regvalue);
 	if (ret < 0) {
 		dev_err(dev, "abx500_get_reg fail %d, %d\n",
 			ret, __LINE__);
@@ -509,32 +489,22 @@ static ssize_t ab8500_val_write(struct file *file,
 	size_t count, loff_t *ppos)
 {
 	struct device *dev = ((struct seq_file *)(file->private_data))->private;
-	char buf[32];
-	int buf_size;
-	unsigned long user_val;
+	u8 user_val;
 	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_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(dev, "debugfs error input > 0xff\n");
-		return -EINVAL;
-	}
+		return err;
+
 	err = abx500_set_register_interruptible(dev,
-		(u8)debug_bank, debug_address, (u8)user_val);
+		debug_bank, debug_address, user_val);
 	if (err < 0) {
 		printk(KERN_ERR "abx500_set_reg failed %d, %d", err, __LINE__);
 		return -EINVAL;
 	}
 
-	return buf_size;
+	return count;
 }
 
 static const struct file_operations ab8500_bank_fops = {
-- 
1.7.3.4