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@xxxxxxxxxx wrote:
>>>> From: Tom Rix <trix@xxxxxxxxxx>
>>>>
>>>> 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@xxxxxxxxxx>
>>>> ---
>>>> 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
>
