[PATCH] iio: percolate error if event fd fails

[PATCH] iio: percolate error if event fd fails

[Linus Walleij]

This makes the error from iio_event_getfd() percolate up
to userspace properly so we can know for sure there is no
events on this device (-ENODEV returned). Before this patch
we would bail out looking for the unsupported evens on the
erroneous (negative) file descriptor.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/industrialio-core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 3524b0de8721..9492aa443a26 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1130,6 +1130,8 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
 		fd = iio_event_getfd(indio_dev);
+		if (fd < 0)
+			return fd;
 		if (copy_to_user(ip, &fd, sizeof(fd)))
 			return -EFAULT;
 		return 0;
-- 
2.4.3

Re: [PATCH] iio: percolate error if event fd fails

[Daniel Baluta]

On Tue, Aug 11, 2015 at 12:56 PM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> This makes the error from iio_event_getfd() percolate up
> to userspace properly so we can know for sure there is no
> events on this device (-ENODEV returned). Before this patch
> we would bail out looking for the unsupported evens on the
> erroneous (negative) file descriptor.

Good catch. s/evens/events

>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Acked-by: Daniel Baluta <daniel.baluta@intel.com>

> ---
>  drivers/iio/industrialio-core.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 3524b0de8721..9492aa443a26 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1130,6 +1130,8 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>
>         if (cmd == IIO_GET_EVENT_FD_IOCTL) {
>                 fd = iio_event_getfd(indio_dev);
> +               if (fd < 0)
> +                       return fd;
>                 if (copy_to_user(ip, &fd, sizeof(fd)))
>                         return -EFAULT;
>                 return 0;
> --
> 2.4.3
>
> --
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Re: [PATCH] iio: percolate error if event fd fails

[Jonathan Cameron]

On 11/08/15 11:52, Daniel Baluta wrote:
> On Tue, Aug 11, 2015 at 12:56 PM, Linus Walleij
> <linus.walleij@linaro.org> wrote:
>> This makes the error from iio_event_getfd() percolate up
>> to userspace properly so we can know for sure there is no
>> events on this device (-ENODEV returned). Before this patch
>> we would bail out looking for the unsupported evens on the
>> erroneous (negative) file descriptor.
> 
> Good catch. s/evens/events
> 
>>
>> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> 
> Acked-by: Daniel Baluta <daniel.baluta@intel.com>
Applied to the togreg branch of iio.git.   Initially pushed
out as testing.  I'm not sending this as a fix as the error
that resulted was downright missleading, but unlikely to
have caused any nasty crashes or similar.

If you think if should be going in faster/ for stable then
let me know.

Jonathan
> 
>> ---
>>  drivers/iio/industrialio-core.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
>> index 3524b0de8721..9492aa443a26 100644
>> --- a/drivers/iio/industrialio-core.c
>> +++ b/drivers/iio/industrialio-core.c
>> @@ -1130,6 +1130,8 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>>
>>         if (cmd == IIO_GET_EVENT_FD_IOCTL) {
>>                 fd = iio_event_getfd(indio_dev);
>> +               if (fd < 0)
>> +                       return fd;
>>                 if (copy_to_user(ip, &fd, sizeof(fd)))
>>                         return -EFAULT;
>>                 return 0;
>> --
>> 2.4.3
>>
>> --
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>> the body of a message to majordomo@vger.kernel.org
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> --
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> 

Re: [PATCH] iio: percolate error if event fd fails

[Linus Walleij]

On Sat, Aug 15, 2015 at 5:22 PM, Jonathan Cameron <jic23@kernel.org> wrote:

> Applied to the togreg branch of iio.git.   Initially pushed
> out as testing.  I'm not sending this as a fix as the error
> that resulted was downright missleading, but unlikely to
> have caused any nasty crashes or similar.
>
> If you think if should be going in faster/ for stable then
> let me know.

Nah. No regression, just general improvenent.

Thanks,
Linus Walleij