| Message ID | 72b53f2cabc15cf3d019041a0ed605ca7c24d19b.1438331416.git.viresh.kumar@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 31, 2015 at 02:08:25PM +0530, Viresh Kumar wrote: > IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there > is no need to do that again from its callers. Drop it. I'd rather keep it as it documents the expected behavior and double unlikely should work just fine. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/input/mouse/alps.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c > index 113d6f1516a5..cef3611a4ccd 100644 > --- a/drivers/input/mouse/alps.c > +++ b/drivers/input/mouse/alps.c > @@ -1365,7 +1365,7 @@ static void alps_report_bare_ps2_packet(struct psmouse *psmouse, > /* On V2 devices the DualPoint Stick reports bare packets */ > dev = priv->dev2; > dev2 = psmouse->dev; > - } else if (unlikely(IS_ERR_OR_NULL(priv->dev3))) { > + } else if (IS_ERR_OR_NULL(priv->dev3)) { > /* Register dev3 mouse if we received PS/2 packet first time */ > if (!IS_ERR(priv->dev3)) > psmouse_queue_work(psmouse, &priv->dev3_register_work, > -- > 2.4.0 > Thanks.
On 31-07-15, 09:58, Dmitry Torokhov wrote: > On Fri, Jul 31, 2015 at 02:08:25PM +0530, Viresh Kumar wrote: > > IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there > > is no need to do that again from its callers. Drop it. > > I'd rather keep it as it documents the expected behavior and double > unlikely should work just fine. TBH, I don't really agree that it is there for documentation. The only purpose of such compiler flags is to try make code more efficient. Anyway, I got to this series as someone asked me to fix this for one of my patches which used unlikely(IS_ERR_OR_NULL()). And so I thought about fixing all sites that are doing double unlikely (that shouldn't hurt for sure). I will leave it to you.
On Saturday 01 August 2015 13:22:51 Viresh Kumar wrote: > On 31-07-15, 09:58, Dmitry Torokhov wrote: > > On Fri, Jul 31, 2015 at 02:08:25PM +0530, Viresh Kumar wrote: > > > IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and > > > there is no need to do that again from its callers. Drop it. > > > > I'd rather keep it as it documents the expected behavior and double > > unlikely should work just fine. > > TBH, I don't really agree that it is there for documentation. The > only purpose of such compiler flags is to try make code more > efficient. > > Anyway, I got to this series as someone asked me to fix this for one > of my patches which used unlikely(IS_ERR_OR_NULL()). And so I > thought about fixing all sites that are doing double unlikely (that > shouldn't hurt for sure). > > I will leave it to you. I think that unlikely() macro here make code more readable. Yes, it is also for compiler optimization, but also for me it looks like Clean Code pattern <https://de.wikipedia.org/wiki/Clean_Code> -- is not it?
On Sat 2015-08-01 13:44:59, Pali Rohár wrote: > On Saturday 01 August 2015 13:22:51 Viresh Kumar wrote: > > On 31-07-15, 09:58, Dmitry Torokhov wrote: > > > On Fri, Jul 31, 2015 at 02:08:25PM +0530, Viresh Kumar wrote: > > > > IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and > > > > there is no need to do that again from its callers. Drop it. > > > > > > I'd rather keep it as it documents the expected behavior and double > > > unlikely should work just fine. > > > > TBH, I don't really agree that it is there for documentation. The > > only purpose of such compiler flags is to try make code more > > efficient. > > > > Anyway, I got to this series as someone asked me to fix this for one > > of my patches which used unlikely(IS_ERR_OR_NULL()). And so I > > thought about fixing all sites that are doing double unlikely (that > > shouldn't hurt for sure). > > > > I will leave it to you. > > I think that unlikely() macro here make code more readable. Yes, it is > also for compiler optimization, but also for me it looks like Clean Code > pattern <https://de.wikipedia.org/wiki/Clean_Code> -- is not it? People know that errors are unlikely, no need to tell them. I'd remove it. Pavel
On Sunday 02 August 2015 17:43:52 Pavel Machek wrote: > On Sat 2015-08-01 13:44:59, Pali Rohár wrote: > > On Saturday 01 August 2015 13:22:51 Viresh Kumar wrote: > > > On 31-07-15, 09:58, Dmitry Torokhov wrote: > > > > On Fri, Jul 31, 2015 at 02:08:25PM +0530, Viresh Kumar wrote: > > > > > IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag > > > > > and there is no need to do that again from its callers. Drop > > > > > it. > > > > > > > > I'd rather keep it as it documents the expected behavior and > > > > double unlikely should work just fine. > > > > > > TBH, I don't really agree that it is there for documentation. The > > > only purpose of such compiler flags is to try make code more > > > efficient. > > > > > > Anyway, I got to this series as someone asked me to fix this for > > > one of my patches which used unlikely(IS_ERR_OR_NULL()). And so > > > I thought about fixing all sites that are doing double unlikely > > > (that shouldn't hurt for sure). > > > > > > I will leave it to you. > > > > I think that unlikely() macro here make code more readable. Yes, it > > is also for compiler optimization, but also for me it looks like > > Clean Code pattern <https://de.wikipedia.org/wiki/Clean_Code> -- > > is not it? > > People know that errors are unlikely, no need to tell them. I'd > remove it. > Pavel Errors and bugs are always unlikely ;-)
diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c index 113d6f1516a5..cef3611a4ccd 100644 --- a/drivers/input/mouse/alps.c +++ b/drivers/input/mouse/alps.c @@ -1365,7 +1365,7 @@ static void alps_report_bare_ps2_packet(struct psmouse *psmouse, /* On V2 devices the DualPoint Stick reports bare packets */ dev = priv->dev2; dev2 = psmouse->dev; - } else if (unlikely(IS_ERR_OR_NULL(priv->dev3))) { + } else if (IS_ERR_OR_NULL(priv->dev3)) { /* Register dev3 mouse if we received PS/2 packet first time */ if (!IS_ERR(priv->dev3)) psmouse_queue_work(psmouse, &priv->dev3_register_work,
IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag and there is no need to do that again from its callers. Drop it. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/input/mouse/alps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)