Re: [PATCH v3] staging: gpib: change return type of t1_delay function to report errors

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Feb 24, 2025 at 10:44:05PM -0300, Rodrigo Gobbi wrote:
> The current code returns "unsigned int" and it doesn't handle errors
> correctly if it happens during ioctl call for t1 delay configuration.
> 
> The ni_usb_t1_delay(), from NI, is the only function returning -1
> at this point. The caller, t1_delay_ioctl(), doesn't check for errors
> and sets board->t1_nano_sec to -1 and returns success.
> The board->t1_nano_sec value is also used in ni_usb_setup_t1_delay()
> besides the ioctl call and a value of -1 is treated as being above 1100ns.
> It may or may not have a noticeable effect, but it's obviously not right
> considering the content of ni_usb_setup_t1_delay().
> 
> Typical delays are in the 200-2000 range, but definitely not more
> than INT_MAX so we can fix this code by changing the return type to int
> and adding a check for errors. While we're at it, lets change the error
> code in ni_usb_t1_delay() from -1 and instead propagate the error from
> ni_usb_write_registers().
> 
> Fixes: 4e127de14fa7 ("staging: gpib: Add National Instruments USB GPIB driver")
> Signed-off-by: Rodrigo Gobbi <rodrigo.gobbi.7@gmail.com>

As other recently submitted patches caused this not to apply, I fixed it
up by hand and got it added to my tree so you wouldn't have to rebase it
again.

thanks!

greg k-h