diff mbox series

[v4] HID: ft260: improve error handling of ft260_hid_feature_report_get()

Message ID 20210511101208.16401-1-michael.zaidman@gmail.com
State Superseded
Headers show
Series [v4] HID: ft260: improve error handling of ft260_hid_feature_report_get() | expand

Commit Message

Michael Zaidman May 11, 2021, 10:12 a.m. UTC
Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver")

The ft260_hid_feature_report_get() checks if the return size matches
the requested size. But the function can also fail with at least -ENOMEM.
Add the < 0 checks.

In ft260_hid_feature_report_get(), do not do the memcpy to the caller's
buffer if there is an error.

---
v4   Fixed commit message
---
v3   Simplify and optimize the changes
---
v2:  add unlikely()'s for error conditions
---

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
---
 drivers/hid/hid-ft260.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

Comments

Tom Rix May 11, 2021, 1:10 p.m. UTC | #1
Generally change is fine.

a nit below.

On 5/11/21 3:12 AM, Michael Zaidman wrote:
> Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver")
>
> The ft260_hid_feature_report_get() checks if the return size matches
> the requested size. But the function can also fail with at least -ENOMEM.
> Add the < 0 checks.
>
> In ft260_hid_feature_report_get(), do not do the memcpy to the caller's
> buffer if there is an error.
>
> ---
> v4   Fixed commit message
> ---
> v3   Simplify and optimize the changes
> ---
> v2:  add unlikely()'s for error conditions
> ---
>
> Signed-off-by: Tom Rix <trix@redhat.com>
> Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
> ---
>   drivers/hid/hid-ft260.c | 24 ++++++++++++------------
>   1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
> index 047aa85a7c83..7f4cb823129e 100644
> --- a/drivers/hid/hid-ft260.c
> +++ b/drivers/hid/hid-ft260.c
> @@ -249,7 +249,10 @@ static int ft260_hid_feature_report_get(struct hid_device *hdev,
>   
>   	ret = hid_hw_raw_request(hdev, report_id, buf, len, HID_FEATURE_REPORT,
>   				 HID_REQ_GET_REPORT);
> -	memcpy(data, buf, len);
> +	if (likely(ret == len))
> +		memcpy(data, buf, len);
> +	else if (ret >= 0)
> +		ret = -EIO;
>   	kfree(buf);
>   	return ret;
>   }
> @@ -298,7 +301,7 @@ static int ft260_xfer_status(struct ft260_device *dev)
>   
>   	ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,
>   					   (u8 *)&report, sizeof(report));
> -	if (ret < 0) {
> +	if (unlikely(ret < 0)) {
>   		hid_err(hdev, "failed to retrieve status: %d\n", ret);
>   		return ret;
>   	}
> @@ -720,10 +723,9 @@ static int ft260_get_system_config(struct hid_device *hdev,
>   
>   	ret = ft260_hid_feature_report_get(hdev, FT260_SYSTEM_SETTINGS,
>   					   (u8 *)cfg, len);
> -	if (ret != len) {
> +	if (ret < 0) {

nit: should be consistent and use unlikely(ret < 0) for this and other 
similar checks.

Tom

>   		hid_err(hdev, "failed to retrieve system status\n");
> -		if (ret >= 0)
> -			return -EIO;
> +		return ret;
>   	}
>   	return 0;
>   }
> @@ -776,8 +778,8 @@ static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len,
>   	int ret;
>   
>   	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
> -	if (ret != len && ret >= 0)
> -		return -EIO;
> +	if (ret < 0)
> +		return ret;
>   
>   	return scnprintf(buf, PAGE_SIZE, "%hi\n", *field);
>   }
> @@ -788,8 +790,8 @@ static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
>   	int ret;
>   
>   	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
> -	if (ret != len && ret >= 0)
> -		return -EIO;
> +	if (ret < 0)
> +		return ret;
>   
>   	return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field));
>   }
> @@ -940,10 +942,8 @@ static int ft260_probe(struct hid_device *hdev, const struct hid_device_id *id)
>   
>   	ret = ft260_hid_feature_report_get(hdev, FT260_CHIP_VERSION,
>   					   (u8 *)&version, sizeof(version));
> -	if (ret != sizeof(version)) {
> +	if (ret < 0) {
>   		hid_err(hdev, "failed to retrieve chip version\n");
> -		if (ret >= 0)
> -			ret = -EIO;
>   		goto err_hid_close;
>   	}
>
Michael Zaidman May 11, 2021, 2:34 p.m. UTC | #2
On Tue, May 11, 2021 at 06:10:36AM -0700, Tom Rix wrote:
> Generally change is fine.
> 
> a nit below.
> 
> On 5/11/21 3:12 AM, Michael Zaidman wrote:
> > Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver")
> > 
> > The ft260_hid_feature_report_get() checks if the return size matches
> > the requested size. But the function can also fail with at least -ENOMEM.
> > Add the < 0 checks.
> > 
> > In ft260_hid_feature_report_get(), do not do the memcpy to the caller's
> > buffer if there is an error.
> > 
> > ---
> > v4   Fixed commit message
> > ---
> > v3   Simplify and optimize the changes
> > ---
> > v2:  add unlikely()'s for error conditions
> > ---
> > 
> > Signed-off-by: Tom Rix <trix@redhat.com>
> > Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
> > ---
> >   drivers/hid/hid-ft260.c | 24 ++++++++++++------------
> >   1 file changed, 12 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
> > index 047aa85a7c83..7f4cb823129e 100644
> > --- a/drivers/hid/hid-ft260.c
> > +++ b/drivers/hid/hid-ft260.c
> > @@ -249,7 +249,10 @@ static int ft260_hid_feature_report_get(struct hid_device *hdev,
> >   	ret = hid_hw_raw_request(hdev, report_id, buf, len, HID_FEATURE_REPORT,
> >   				 HID_REQ_GET_REPORT);
> > -	memcpy(data, buf, len);
> > +	if (likely(ret == len))
> > +		memcpy(data, buf, len);
> > +	else if (ret >= 0)
> > +		ret = -EIO;
> >   	kfree(buf);
> >   	return ret;
> >   }
> > @@ -298,7 +301,7 @@ static int ft260_xfer_status(struct ft260_device *dev)
> >   	ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,
> >   					   (u8 *)&report, sizeof(report));
> > -	if (ret < 0) {
> > +	if (unlikely(ret < 0)) {
> >   		hid_err(hdev, "failed to retrieve status: %d\n", ret);
> >   		return ret;
> >   	}
> > @@ -720,10 +723,9 @@ static int ft260_get_system_config(struct hid_device *hdev,
> >   	ret = ft260_hid_feature_report_get(hdev, FT260_SYSTEM_SETTINGS,
> >   					   (u8 *)cfg, len);
> > -	if (ret != len) {
> > +	if (ret < 0) {
> 
> nit: should be consistent and use unlikely(ret < 0) for this and other
> similar checks.
> 
> Tom

I preserved the likely/unlikely hints in the critical path where the
performance matters. And for the sake of consistency, I removed them from
the rest of the places that are called rarely and are not performance-critical
to be aligned to the other "if" statements in the code.

Michael
Jiri Kosina May 13, 2021, 11:09 a.m. UTC | #3
On Tue, 11 May 2021, Michael Zaidman wrote:

> Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver")

> 

> The ft260_hid_feature_report_get() checks if the return size matches

> the requested size. But the function can also fail with at least -ENOMEM.

> Add the < 0 checks.

> 

> In ft260_hid_feature_report_get(), do not do the memcpy to the caller's

> buffer if there is an error.

> 

> ---

> v4   Fixed commit message

> ---

> v3   Simplify and optimize the changes

> ---

> v2:  add unlikely()'s for error conditions

> ---

> 

> Signed-off-by: Tom Rix <trix@redhat.com>

> Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>


Who should be the author of the git commit?

Thanks,

-- 
Jiri Kosina
SUSE Labs
Tom Rix May 13, 2021, 1:15 p.m. UTC | #4
On 5/13/21 4:09 AM, Jiri Kosina wrote:
> On Tue, 11 May 2021, Michael Zaidman wrote:
>
>> Fixes: 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver")
>>
>> The ft260_hid_feature_report_get() checks if the return size matches
>> the requested size. But the function can also fail with at least -ENOMEM.
>> Add the < 0 checks.
>>
>> In ft260_hid_feature_report_get(), do not do the memcpy to the caller's
>> buffer if there is an error.
>>
>> ---
>> v4   Fixed commit message
>> ---
>> v3   Simplify and optimize the changes
>> ---
>> v2:  add unlikely()'s for error conditions
>> ---
>>
>> Signed-off-by: Tom Rix <trix@redhat.com>
>> Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
> Who should be the author of the git commit?

Go with the latest patch's author, Micheal.

Tom

>
> Thanks,
>
diff mbox series

Patch

diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
index 047aa85a7c83..7f4cb823129e 100644
--- a/drivers/hid/hid-ft260.c
+++ b/drivers/hid/hid-ft260.c
@@ -249,7 +249,10 @@  static int ft260_hid_feature_report_get(struct hid_device *hdev,
 
 	ret = hid_hw_raw_request(hdev, report_id, buf, len, HID_FEATURE_REPORT,
 				 HID_REQ_GET_REPORT);
-	memcpy(data, buf, len);
+	if (likely(ret == len))
+		memcpy(data, buf, len);
+	else if (ret >= 0)
+		ret = -EIO;
 	kfree(buf);
 	return ret;
 }
@@ -298,7 +301,7 @@  static int ft260_xfer_status(struct ft260_device *dev)
 
 	ret = ft260_hid_feature_report_get(hdev, FT260_I2C_STATUS,
 					   (u8 *)&report, sizeof(report));
-	if (ret < 0) {
+	if (unlikely(ret < 0)) {
 		hid_err(hdev, "failed to retrieve status: %d\n", ret);
 		return ret;
 	}
@@ -720,10 +723,9 @@  static int ft260_get_system_config(struct hid_device *hdev,
 
 	ret = ft260_hid_feature_report_get(hdev, FT260_SYSTEM_SETTINGS,
 					   (u8 *)cfg, len);
-	if (ret != len) {
+	if (ret < 0) {
 		hid_err(hdev, "failed to retrieve system status\n");
-		if (ret >= 0)
-			return -EIO;
+		return ret;
 	}
 	return 0;
 }
@@ -776,8 +778,8 @@  static int ft260_byte_show(struct hid_device *hdev, int id, u8 *cfg, int len,
 	int ret;
 
 	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
-	if (ret != len && ret >= 0)
-		return -EIO;
+	if (ret < 0)
+		return ret;
 
 	return scnprintf(buf, PAGE_SIZE, "%hi\n", *field);
 }
@@ -788,8 +790,8 @@  static int ft260_word_show(struct hid_device *hdev, int id, u8 *cfg, int len,
 	int ret;
 
 	ret = ft260_hid_feature_report_get(hdev, id, cfg, len);
-	if (ret != len && ret >= 0)
-		return -EIO;
+	if (ret < 0)
+		return ret;
 
 	return scnprintf(buf, PAGE_SIZE, "%hi\n", le16_to_cpu(*field));
 }
@@ -940,10 +942,8 @@  static int ft260_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	ret = ft260_hid_feature_report_get(hdev, FT260_CHIP_VERSION,
 					   (u8 *)&version, sizeof(version));
-	if (ret != sizeof(version)) {
+	if (ret < 0) {
 		hid_err(hdev, "failed to retrieve chip version\n");
-		if (ret >= 0)
-			ret = -EIO;
 		goto err_hid_close;
 	}