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

From: trix
Date: Sat Mar 12 2022 - 10:12:49 EST


From: Tom Rix <trix@xxxxxxxxxx>

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@xxxxxxxxxx>
---
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