[PATCH] platform/x86: thinkpad_acpi: consistently check fan_get_status return.

[PATCH] platform/x86: thinkpad_acpi: consistently check fan_get_status return.

[trix]

From: Tom Rix <trix@redhat.com>

Clang static analysis returns this false positive
thinkpad_acpi.c:8926:19: warning: The left operand
  of '!=' is a garbage value
  (status != 0) ? "enabled" : "disabled", status);
   ~~~~~~ ^

The return of fan_get_status* is checked inconsistenly.
Sometime ret < 0 is an error, sometimes !ret.
Both fan_get_status() and fan_get_status_safe() return
0 on success and return negative otherwise.  Change
the checks for error, ret < 0, into checks for
not success, !ret.

Signed-off-by: Tom Rix <trix@redhat.com>
---
 drivers/platform/x86/thinkpad_acpi.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 708743ec9ae79..c568fae56db29 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -8285,7 +8285,7 @@ static int fan_set_enable(void)
 	case TPACPI_FAN_WR_ACPI_FANS:
 	case TPACPI_FAN_WR_TPEC:
 		rc = fan_get_status(&s);
-		if (rc < 0)
+		if (rc)
 			break;
 
 		/* Don't go out of emergency fan mode */
@@ -8304,7 +8304,7 @@ static int fan_set_enable(void)
 
 	case TPACPI_FAN_WR_ACPI_SFAN:
 		rc = fan_get_status(&s);
-		if (rc < 0)
+		if (rc)
 			break;
 
 		s &= 0x07;
@@ -8843,7 +8843,7 @@ static void fan_suspend(void)
 	/* Store fan status in cache */
 	fan_control_resume_level = 0;
 	rc = fan_get_status_safe(&fan_control_resume_level);
-	if (rc < 0)
+	if (rc)
 		pr_notice("failed to read fan level for later restore during resume: %d\n",
 			  rc);
 
@@ -8864,7 +8864,7 @@ static void fan_resume(void)
 
 	if (!fan_control_allowed ||
 	    !fan_control_resume_level ||
-	    (fan_get_status_safe(&current_level) < 0))
+	    fan_get_status_safe(&current_level))
 		return;
 
 	switch (fan_control_access_mode) {
@@ -8918,7 +8918,7 @@ static int fan_read(struct seq_file *m)
 	case TPACPI_FAN_RD_ACPI_GFAN:
 		/* 570, 600e/x, 770e, 770x */
 		rc = fan_get_status_safe(&status);
-		if (rc < 0)
+		if (rc)
 			return rc;
 
 		seq_printf(m, "status:\t\t%s\n"
@@ -8929,7 +8929,7 @@ static int fan_read(struct seq_file *m)
 	case TPACPI_FAN_RD_TPEC:
 		/* all except 570, 600e/x, 770e, 770x */
 		rc = fan_get_status_safe(&status);
-		if (rc < 0)
+		if (rc)
 			return rc;
 
 		seq_printf(m, "status:\t\t%s\n",
-- 
2.26.3

Re: [PATCH] platform/x86: thinkpad_acpi: consistently check fan_get_status return.

[Hans de Goede]

Hi,

On 3/12/22 15:53, trix@redhat.com wrote:
> From: Tom Rix <trix@redhat.com>
> 
> Clang static analysis returns this false positive
> thinkpad_acpi.c:8926:19: warning: The left operand
>   of '!=' is a garbage value
>   (status != 0) ? "enabled" : "disabled", status);
>    ~~~~~~ ^
> 
> The return of fan_get_status* is checked inconsistenly.
> Sometime ret < 0 is an error, sometimes !ret.
> Both fan_get_status() and fan_get_status_safe() return
> 0 on success and return negative otherwise.  Change
> the checks for error, ret < 0, into checks for
> not success, !ret.
> 
> Signed-off-by: Tom Rix <trix@redhat.com>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans

> ---
>  drivers/platform/x86/thinkpad_acpi.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index 708743ec9ae79..c568fae56db29 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -8285,7 +8285,7 @@ static int fan_set_enable(void)
>  	case TPACPI_FAN_WR_ACPI_FANS:
>  	case TPACPI_FAN_WR_TPEC:
>  		rc = fan_get_status(&s);
> -		if (rc < 0)
> +		if (rc)
>  			break;
>  
>  		/* Don't go out of emergency fan mode */
> @@ -8304,7 +8304,7 @@ static int fan_set_enable(void)
>  
>  	case TPACPI_FAN_WR_ACPI_SFAN:
>  		rc = fan_get_status(&s);
> -		if (rc < 0)
> +		if (rc)
>  			break;
>  
>  		s &= 0x07;
> @@ -8843,7 +8843,7 @@ static void fan_suspend(void)
>  	/* Store fan status in cache */
>  	fan_control_resume_level = 0;
>  	rc = fan_get_status_safe(&fan_control_resume_level);
> -	if (rc < 0)
> +	if (rc)
>  		pr_notice("failed to read fan level for later restore during resume: %d\n",
>  			  rc);
>  
> @@ -8864,7 +8864,7 @@ static void fan_resume(void)
>  
>  	if (!fan_control_allowed ||
>  	    !fan_control_resume_level ||
> -	    (fan_get_status_safe(&current_level) < 0))
> +	    fan_get_status_safe(&current_level))
>  		return;
>  
>  	switch (fan_control_access_mode) {
> @@ -8918,7 +8918,7 @@ static int fan_read(struct seq_file *m)
>  	case TPACPI_FAN_RD_ACPI_GFAN:
>  		/* 570, 600e/x, 770e, 770x */
>  		rc = fan_get_status_safe(&status);
> -		if (rc < 0)
> +		if (rc)
>  			return rc;
>  
>  		seq_printf(m, "status:\t\t%s\n"
> @@ -8929,7 +8929,7 @@ static int fan_read(struct seq_file *m)
>  	case TPACPI_FAN_RD_TPEC:
>  		/* all except 570, 600e/x, 770e, 770x */
>  		rc = fan_get_status_safe(&status);
> -		if (rc < 0)
> +		if (rc)
>  			return rc;
>  
>  		seq_printf(m, "status:\t\t%s\n",