* [PATCH] USB: realtek_cr: fix return check for dma functions
@ 2020-08-11 15:15 trix
2020-08-11 16:03 ` Alan Stern
0 siblings, 1 reply; 6+ messages in thread
From: trix @ 2020-08-11 15:15 UTC (permalink / raw)
To: stern, gregkh, acozzette; +Cc: linux-usb, usb-storage, linux-kernel, Tom Rix
From: Tom Rix <trix@redhat.com>
clang static analysis reports this representative problem
realtek_cr.c:639:3: warning: The left expression of the compound
assignment is an uninitialized value. The computed value will
also be garbage
SET_BIT(value, 2);
^~~~~~~~~~~~~~~~~
value is set by a successful call to rts51x_read_mem()
retval = rts51x_read_mem(us, 0xFE77, &value, 1);
if (retval < 0)
return -EIO;
A successful call to rts51x_read_mem returns 0, failure can
return positive and negative values. This check is wrong
for a number of functions. Fix the retval check.
Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
Signed-off-by: Tom Rix <trix@redhat.com>
---
drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
index 3789698d9d3c..b983753e2368 100644
--- a/drivers/usb/storage/realtek_cr.c
+++ b/drivers/usb/storage/realtek_cr.c
@@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
u8 value;
retval = rts51x_read_mem(us, 0xFE77, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
value |= 0x04;
retval = rts51x_write_mem(us, 0xFE77, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
retval = rts51x_read_mem(us, 0xFE77, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
if (!(value & 0x04))
@@ -533,7 +533,7 @@ static int do_config_autodelink(struct us_data *us, int enable, int force)
u8 value;
retval = rts51x_read_mem(us, 0xFE47, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
if (enable) {
@@ -549,7 +549,7 @@ static int do_config_autodelink(struct us_data *us, int enable, int force)
/* retval = rts51x_write_mem(us, 0xFE47, &value, 1); */
retval = __do_config_autodelink(us, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
return 0;
@@ -565,7 +565,7 @@ static int config_autodelink_after_power_on(struct us_data *us)
return 0;
retval = rts51x_read_mem(us, 0xFE47, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
if (auto_delink_en) {
@@ -580,7 +580,7 @@ static int config_autodelink_after_power_on(struct us_data *us)
/* retval = rts51x_write_mem(us, 0xFE47, &value, 1); */
retval = __do_config_autodelink(us, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
retval = enable_oscillator(us);
@@ -602,18 +602,18 @@ static int config_autodelink_after_power_on(struct us_data *us)
/* retval = rts51x_write_mem(us, 0xFE47, &value, 1); */
retval = __do_config_autodelink(us, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
if (CHECK_ID(chip, 0x0159, 0x5888)) {
value = 0xFF;
retval = rts51x_write_mem(us, 0xFE79, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
value = 0x01;
retval = rts51x_write_mem(us, 0x48, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
}
}
@@ -633,37 +633,37 @@ static int config_autodelink_before_power_down(struct us_data *us)
if (auto_delink_en) {
retval = rts51x_read_mem(us, 0xFE77, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
SET_BIT(value, 2);
retval = rts51x_write_mem(us, 0xFE77, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
if (CHECK_ID(chip, 0x0159, 0x5888)) {
value = 0x01;
retval = rts51x_write_mem(us, 0x48, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
}
retval = rts51x_read_mem(us, 0xFE47, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
SET_BIT(value, 0);
if (CHECK_ID(chip, 0x0138, 0x3882))
SET_BIT(value, 2);
retval = rts51x_write_mem(us, 0xFE77, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
} else {
if (CHECK_ID(chip, 0x0159, 0x5889) ||
CHECK_ID(chip, 0x0138, 0x3880) ||
CHECK_ID(chip, 0x0138, 0x3882)) {
retval = rts51x_read_mem(us, 0xFE47, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
if (CHECK_ID(chip, 0x0159, 0x5889) ||
@@ -677,14 +677,14 @@ static int config_autodelink_before_power_down(struct us_data *us)
/* retval = rts51x_write_mem(us, 0xFE47, &value, 1); */
retval = __do_config_autodelink(us, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
}
if (CHECK_ID(chip, 0x0159, 0x5888)) {
value = 0x01;
retval = rts51x_write_mem(us, 0x48, &value, 1);
- if (retval < 0)
+ if (retval != STATUS_SUCCESS)
return -EIO;
}
}
--
2.18.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] USB: realtek_cr: fix return check for dma functions
2020-08-11 15:15 [PATCH] USB: realtek_cr: fix return check for dma functions trix
@ 2020-08-11 16:03 ` Alan Stern
2020-08-11 17:29 ` Tom Rix
0 siblings, 1 reply; 6+ messages in thread
From: Alan Stern @ 2020-08-11 16:03 UTC (permalink / raw)
To: trix; +Cc: gregkh, acozzette, linux-usb, usb-storage, linux-kernel
On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@redhat.com wrote:
> From: Tom Rix <trix@redhat.com>
>
> clang static analysis reports this representative problem
>
> realtek_cr.c:639:3: warning: The left expression of the compound
> assignment is an uninitialized value. The computed value will
> also be garbage
> SET_BIT(value, 2);
> ^~~~~~~~~~~~~~~~~
>
> value is set by a successful call to rts51x_read_mem()
>
> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
> if (retval < 0)
> return -EIO;
>
> A successful call to rts51x_read_mem returns 0, failure can
> return positive and negative values. This check is wrong
> for a number of functions. Fix the retval check.
>
> Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
> drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
> 1 file changed, 18 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
> index 3789698d9d3c..b983753e2368 100644
> --- a/drivers/usb/storage/realtek_cr.c
> +++ b/drivers/usb/storage/realtek_cr.c
> @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
> u8 value;
>
> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
> - if (retval < 0)
> + if (retval != STATUS_SUCCESS)
> return -EIO;
Instead of changing all these call sites, wouldn't it be a lot easier
just to change rts51x_read_mem() to make it always return a negative
value (such as -EIO) when there's an error?
Alan Stern
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] USB: realtek_cr: fix return check for dma functions
2020-08-11 16:03 ` Alan Stern
@ 2020-08-11 17:29 ` Tom Rix
2020-08-11 17:53 ` Alan Stern
0 siblings, 1 reply; 6+ messages in thread
From: Tom Rix @ 2020-08-11 17:29 UTC (permalink / raw)
To: Alan Stern; +Cc: gregkh, acozzette, linux-usb, usb-storage, linux-kernel
On 8/11/20 9:03 AM, Alan Stern wrote:
> On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@redhat.com wrote:
>> From: Tom Rix <trix@redhat.com>
>>
>> clang static analysis reports this representative problem
>>
>> realtek_cr.c:639:3: warning: The left expression of the compound
>> assignment is an uninitialized value. The computed value will
>> also be garbage
>> SET_BIT(value, 2);
>> ^~~~~~~~~~~~~~~~~
>>
>> value is set by a successful call to rts51x_read_mem()
>>
>> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
>> if (retval < 0)
>> return -EIO;
>>
>> A successful call to rts51x_read_mem returns 0, failure can
>> return positive and negative values. This check is wrong
>> for a number of functions. Fix the retval check.
>>
>> Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
>> Signed-off-by: Tom Rix <trix@redhat.com>
>> ---
>> drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
>> 1 file changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
>> index 3789698d9d3c..b983753e2368 100644
>> --- a/drivers/usb/storage/realtek_cr.c
>> +++ b/drivers/usb/storage/realtek_cr.c
>> @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
>> u8 value;
>>
>> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
>> - if (retval < 0)
>> + if (retval != STATUS_SUCCESS)
>> return -EIO;
> Instead of changing all these call sites, wouldn't it be a lot easier
> just to change rts51x_read_mem() to make it always return a negative
> value (such as -EIO) when there's an error?
>
> Alan Stern
I thought about that but there was already existing (retval != STATUS_SUCCESS) checks for these calls.
Tom
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] USB: realtek_cr: fix return check for dma functions
2020-08-11 17:29 ` Tom Rix
@ 2020-08-11 17:53 ` Alan Stern
2020-08-11 18:54 ` Tom Rix
0 siblings, 1 reply; 6+ messages in thread
From: Alan Stern @ 2020-08-11 17:53 UTC (permalink / raw)
To: Tom Rix; +Cc: gregkh, acozzette, linux-usb, usb-storage, linux-kernel
On Tue, Aug 11, 2020 at 10:29:29AM -0700, Tom Rix wrote:
>
> On 8/11/20 9:03 AM, Alan Stern wrote:
> > On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@redhat.com wrote:
> >> From: Tom Rix <trix@redhat.com>
> >>
> >> clang static analysis reports this representative problem
> >>
> >> realtek_cr.c:639:3: warning: The left expression of the compound
> >> assignment is an uninitialized value. The computed value will
> >> also be garbage
> >> SET_BIT(value, 2);
> >> ^~~~~~~~~~~~~~~~~
> >>
> >> value is set by a successful call to rts51x_read_mem()
> >>
> >> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
> >> if (retval < 0)
> >> return -EIO;
> >>
> >> A successful call to rts51x_read_mem returns 0, failure can
> >> return positive and negative values. This check is wrong
> >> for a number of functions. Fix the retval check.
> >>
> >> Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
> >> Signed-off-by: Tom Rix <trix@redhat.com>
> >> ---
> >> drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
> >> 1 file changed, 18 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
> >> index 3789698d9d3c..b983753e2368 100644
> >> --- a/drivers/usb/storage/realtek_cr.c
> >> +++ b/drivers/usb/storage/realtek_cr.c
> >> @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
> >> u8 value;
> >>
> >> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
> >> - if (retval < 0)
> >> + if (retval != STATUS_SUCCESS)
> >> return -EIO;
> > Instead of changing all these call sites, wouldn't it be a lot easier
> > just to change rts51x_read_mem() to make it always return a negative
> > value (such as -EIO) when there's an error?
> >
> > Alan Stern
>
> I thought about that but there was already existing (retval !=
> STATUS_SUCCESS) checks for these calls.
The only values that routine currently returns are
USB_STOR_TRANSPORT_ERROR, -EIO, and 0. None of the callers distinguish
between the first two values, so you can just change the first to the
second.
Note that STATUS_SUCCESS is simply 0.
Alan Stern
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] USB: realtek_cr: fix return check for dma functions
2020-08-11 17:53 ` Alan Stern
@ 2020-08-11 18:54 ` Tom Rix
2020-08-11 19:43 ` Alan Stern
0 siblings, 1 reply; 6+ messages in thread
From: Tom Rix @ 2020-08-11 18:54 UTC (permalink / raw)
To: Alan Stern; +Cc: gregkh, acozzette, linux-usb, usb-storage, linux-kernel
On 8/11/20 10:53 AM, Alan Stern wrote:
> On Tue, Aug 11, 2020 at 10:29:29AM -0700, Tom Rix wrote:
>> On 8/11/20 9:03 AM, Alan Stern wrote:
>>> On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@redhat.com wrote:
>>>> From: Tom Rix <trix@redhat.com>
>>>>
>>>> clang static analysis reports this representative problem
>>>>
>>>> realtek_cr.c:639:3: warning: The left expression of the compound
>>>> assignment is an uninitialized value. The computed value will
>>>> also be garbage
>>>> SET_BIT(value, 2);
>>>> ^~~~~~~~~~~~~~~~~
>>>>
>>>> value is set by a successful call to rts51x_read_mem()
>>>>
>>>> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
>>>> if (retval < 0)
>>>> return -EIO;
>>>>
>>>> A successful call to rts51x_read_mem returns 0, failure can
>>>> return positive and negative values. This check is wrong
>>>> for a number of functions. Fix the retval check.
>>>>
>>>> Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
>>>> Signed-off-by: Tom Rix <trix@redhat.com>
>>>> ---
>>>> drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
>>>> 1 file changed, 18 insertions(+), 18 deletions(-)
>>>>
>>>> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
>>>> index 3789698d9d3c..b983753e2368 100644
>>>> --- a/drivers/usb/storage/realtek_cr.c
>>>> +++ b/drivers/usb/storage/realtek_cr.c
>>>> @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
>>>> u8 value;
>>>>
>>>> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
>>>> - if (retval < 0)
>>>> + if (retval != STATUS_SUCCESS)
>>>> return -EIO;
>>> Instead of changing all these call sites, wouldn't it be a lot easier
>>> just to change rts51x_read_mem() to make it always return a negative
>>> value (such as -EIO) when there's an error?
>>>
>>> Alan Stern
>> I thought about that but there was already existing (retval !=
>> STATUS_SUCCESS) checks for these calls.
> The only values that routine currently returns are
> USB_STOR_TRANSPORT_ERROR, -EIO, and 0. None of the callers distinguish
> between the first two values, so you can just change the first to the
> second.
>
> Note that STATUS_SUCCESS is simply 0.
Yes, i noted all of these already. My change is consistent with the existing correct checks. consistency is important. returning a neg value to reuse the exiting check should mean the STATUS_SUCCESS != 0 checks are changed to neg check. i can do this larger change if required.
Tom
>
> Alan Stern
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] USB: realtek_cr: fix return check for dma functions
2020-08-11 18:54 ` Tom Rix
@ 2020-08-11 19:43 ` Alan Stern
0 siblings, 0 replies; 6+ messages in thread
From: Alan Stern @ 2020-08-11 19:43 UTC (permalink / raw)
To: Tom Rix; +Cc: gregkh, acozzette, linux-usb, usb-storage, linux-kernel
On Tue, Aug 11, 2020 at 11:54:28AM -0700, Tom Rix wrote:
>
> On 8/11/20 10:53 AM, Alan Stern wrote:
> >>> Instead of changing all these call sites, wouldn't it be a lot easier
> >>> just to change rts51x_read_mem() to make it always return a negative
> >>> value (such as -EIO) when there's an error?
> >>>
> >>> Alan Stern
> >> I thought about that but there was already existing (retval !=
> >> STATUS_SUCCESS) checks for these calls.
> > The only values that routine currently returns are
> > USB_STOR_TRANSPORT_ERROR, -EIO, and 0. None of the callers distinguish
> > between the first two values, so you can just change the first to the
> > second.
> >
> > Note that STATUS_SUCCESS is simply 0.
>
> Yes, i noted all of these already. My change is consistent with the
> existing correct checks. consistency is important. returning a neg
> value to reuse the exiting check should mean the STATUS_SUCCESS != 0
> checks are changed to neg check.
Do you mean the "retval == STATUS_SUCCESS" checks? Those checks would
end up doing exactly the same thing as they do now, since
USB_STOR_TRANSPORT_ERROR and -EIO are both different from 0.
Yes, it is true that consistency is important. But correctness is more
important than consistency.
> i can do this larger change if
> required.
Let me put it this way: Suppose you changed the USB_STOR_TRANSPORT_ERROR
in rts51x_read_mem() to -EIO, without changing anything else. Wouldn't
that fix the problem reported by the clang static analysis? If not, why
not?
Alan Stern
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-08-11 19:43 UTC | newest]
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2020-08-11 15:15 [PATCH] USB: realtek_cr: fix return check for dma functions trix
2020-08-11 16:03 ` Alan Stern
2020-08-11 17:29 ` Tom Rix
2020-08-11 17:53 ` Alan Stern
2020-08-11 18:54 ` Tom Rix
2020-08-11 19:43 ` Alan Stern
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