| Message ID | 1335309230-23428-1-git-send-email-krzysztof.wilczynski@linux.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com> Date: Wed, 25 Apr 2012 00:13:50 +0100 > Function hfcpci_softirq uses driver_for_each_device to call _hfcpci_softirq for > each device. Given that _hfcpci_softirq always returns 0, we collect this return > value and simply do nothing with it. This is purely to address the following > warning during compilation time: > > drivers/isdn/hardware/mISDN/hfcpci.c: In function ‘hfcpci_softirq’: > drivers/isdn/hardware/mISDN/hfcpci.c:2319: warning: ignoring return value of > ‘driver_for_each_device’, declared with attribute warn_unused_result > > Similar approach was used in function cx18_alsa_exit from "cx18-alsa-main.c". > > Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com> There is no value in the warning if we simply convert each such case to ignore the return value. I'm not applying this, at least not with a more intelligent analysis of why any error or other non-zero value signalled by driver_for_each_device should be completely ignored, and no error handling should be performed.
Hi, [...] > I'm not applying this, at least not with a more intelligent analysis > of why any error or other non-zero value signalled by > driver_for_each_device should be completely ignored, and no error > handling should be performed. This is a fair point. It should not be ignored. I was looking through the code and found few cases where the return value was not checked for potential errors (I assume that it was collected to avoid warning being produced, but that was about it) without printing an error message. The following could most certainly use better error reporting concerning use of driver_for_each_device: drivers/isdn/hardware/mISDN/hfcpci.c drivers/media/video/cx18/cx18-alsa-main.c drivers/media/video/ivtv/ivtvfb.c I will look into it making suitable changes. Thanks for pointing it out to me! :) KW -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c index e2c83a2..f0d0180 100644 --- a/drivers/isdn/hardware/mISDN/hfcpci.c +++ b/drivers/isdn/hardware/mISDN/hfcpci.c @@ -2316,8 +2316,11 @@ _hfcpci_softirq(struct device *dev, void *arg) static void hfcpci_softirq(void *arg) { - (void) driver_for_each_device(&hfc_driver.driver, NULL, arg, - _hfcpci_softirq); + int ret; + + /* Collect return value, but do not use it; suppress GCC warning ... */ + ret = driver_for_each_device(&hfc_driver.driver, NULL, arg, + _hfcpci_softirq); /* if next event would be in the past ... */ if ((s32)(hfc_jiffies + tics - jiffies) <= 0)
Function hfcpci_softirq uses driver_for_each_device to call _hfcpci_softirq for each device. Given that _hfcpci_softirq always returns 0, we collect this return value and simply do nothing with it. This is purely to address the following warning during compilation time: drivers/isdn/hardware/mISDN/hfcpci.c: In function ‘hfcpci_softirq’: drivers/isdn/hardware/mISDN/hfcpci.c:2319: warning: ignoring return value of ‘driver_for_each_device’, declared with attribute warn_unused_result Similar approach was used in function cx18_alsa_exit from "cx18-alsa-main.c". Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com> --- drivers/isdn/hardware/mISDN/hfcpci.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)