Messages in this thread | | | Date | Sun, 22 Nov 2015 12:36:53 +0200 | Subject | Re: [PATCH v5 5/5] Add ioctls to enable and disable local controls on an instrument | From | Andy Shevchenko <> |
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On Sun, Nov 22, 2015 at 10:51 AM, Dave Penkler <dpenkler@gmail.com> wrote: > On Wed, Nov 18, 2015 at 11:41:30AM +0200, Andy Shevchenko wrote: >> On Wed, Nov 18, 2015 at 10:38 AM, Dave Penkler <dpenkler@gmail.com> wrote:
>> > + if (rv < 0) { >> > + dev_err(dev, "simple usb_control_msg failed %d\n", rv); >> > + goto exit; >> > + } else if (rv != 1) { >> > + dev_warn(dev, "simple usb_control_msg returned %d\n", rv); >> >> Actually here what king of results could be? 0? 2+? In all cases of >> error you have to provide an error code. >> > > We seem to be going round in circles here, last time you suggested to > propagate the return value.
You didn't pay much attention to where I put my comment. You have few branches depending on return value
1) negative, apparently an error code, should be propagated if nothing specific to framework; 2) zero, what does it means? 3) one, seems the expected result when success, so, error code should be 0; 4) two, three, … non-negative numbers,see 2).
For my understanding 2) and 4) have to return what you initially had -EIO.
> The non-negative return is the number of bytes > transferred which should be 1 unless there is some usb implementation > flakiness happening. So I will go back to returning -EIO.
Yes, in *this* branch.
> >> > + goto exit; >> > + } >> > + >> > + if (buffer[0] != USBTMC_STATUS_SUCCESS) { >> > + dev_err(dev, "simple control status returned %x\n", buffer[0]); >> > + rv = -EIO; >> > + goto exit; >> > + } >> > + rv = 0; >> > + >> > + exit: >> > + kfree(buffer); >> > + return rv; >> > +}
-- With Best Regards, Andy Shevchenko
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