Message ID | 20191004162156.325-1-colin.king@canonical.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [next] drm/komeda: remove redundant assignment to pointer disable_done | expand |
On Fri, Oct 04, 2019 at 05:21:56PM +0100, Colin King wrote: > From: Colin Ian King <colin.king@canonical.com> > > The pointer disable_done is being initialized with a value that > is never read and is being re-assigned a little later on. The > assignment is redundant and hence can be removed. Not really true, isn't it? The re-assignment is done under the condition that crtc->state->active is true. disable_done will be used regardless after the if block, so we can't skip this initialisation. Not sure why Coverity flags this, but I would NAK this patch. Best regards, Liviu > > Addresses-Coverity: ("Unused value") > Signed-off-by: Colin Ian King <colin.king@canonical.com> > --- > drivers/gpu/drm/arm/display/komeda/komeda_crtc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c > index 75263d8cd0bd..9beeda04818b 100644 > --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c > @@ -296,7 +296,7 @@ komeda_crtc_atomic_disable(struct drm_crtc *crtc, > struct komeda_crtc_state *old_st = to_kcrtc_st(old); > struct komeda_pipeline *master = kcrtc->master; > struct komeda_pipeline *slave = kcrtc->slave; > - struct completion *disable_done = &crtc->state->commit->flip_done; > + struct completion *disable_done; > bool needs_phase2 = false; > > DRM_DEBUG_ATOMIC("CRTC%d_DISABLE: active_pipes: 0x%x, affected: 0x%x\n", > -- > 2.20.1 >
On 04/10/2019 20:27, Liviu Dudau wrote: > On Fri, Oct 04, 2019 at 05:21:56PM +0100, Colin King wrote: >> From: Colin Ian King <colin.king@canonical.com> >> >> The pointer disable_done is being initialized with a value that >> is never read and is being re-assigned a little later on. The >> assignment is redundant and hence can be removed. > > Not really true, isn't it? The re-assignment is done under the condition that > crtc->state->active is true. disable_done will be used regardless after the if > block, so we can't skip this initialisation. > > Not sure why Coverity flags this, but I would NAK this patch. I'm patching against the driver from linux-next so I believe this is OK for that. I believe your statement is true against linux which does not have commit: d6cb013579e743bc7bc5590ca35a1943f2b8f3c8 Author: Lowry Li (Arm Technology China) <Lowry.Li@arm.com> Date: Fri Sep 6 07:18:06 2019 +0000 Colin. > > Best regards, > Liviu > >> >> Addresses-Coverity: ("Unused value") >> Signed-off-by: Colin Ian King <colin.king@canonical.com> >> --- >> drivers/gpu/drm/arm/display/komeda/komeda_crtc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c >> index 75263d8cd0bd..9beeda04818b 100644 >> --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c >> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c >> @@ -296,7 +296,7 @@ komeda_crtc_atomic_disable(struct drm_crtc *crtc, >> struct komeda_crtc_state *old_st = to_kcrtc_st(old); >> struct komeda_pipeline *master = kcrtc->master; >> struct komeda_pipeline *slave = kcrtc->slave; >> - struct completion *disable_done = &crtc->state->commit->flip_done; >> + struct completion *disable_done; >> bool needs_phase2 = false; >> >> DRM_DEBUG_ATOMIC("CRTC%d_DISABLE: active_pipes: 0x%x, affected: 0x%x\n", >> -- >> 2.20.1 >> >
On Fri, Oct 04, 2019 at 10:53:44PM +0100, Colin Ian King wrote: > On 04/10/2019 20:27, Liviu Dudau wrote: > > On Fri, Oct 04, 2019 at 05:21:56PM +0100, Colin King wrote: > >> From: Colin Ian King <colin.king@canonical.com> > >> > >> The pointer disable_done is being initialized with a value that > >> is never read and is being re-assigned a little later on. The > >> assignment is redundant and hence can be removed. > > > > Not really true, isn't it? The re-assignment is done under the condition that > > crtc->state->active is true. disable_done will be used regardless after the if > > block, so we can't skip this initialisation. > > > > Not sure why Coverity flags this, but I would NAK this patch. > > I'm patching against the driver from linux-next so I believe this is OK > for that. I believe your statement is true against linux which does not > have commit: > > d6cb013579e743bc7bc5590ca35a1943f2b8f3c8 > Author: Lowry Li (Arm Technology China) <Lowry.Li@arm.com> > Date: Fri Sep 6 07:18:06 2019 +0000 > It really does help reviewing patches when this is mentioned in the commit message. There is some debate about whether this should be mentioned as a Fixes since it doesn't fix a bug. I initialy felt it shouldn't be, but now I think enough people think it should be listed as Fixes that I must be wrong. Either way, it's very useful information. The other thing is that soon get_maintainer.pl will start CC'ing people from the Fixes tag and right now Lowry Li is not CC'd so that's unfortunate. regards, dan carpenter
On Mon, Oct 07, 2019 at 04:25:05PM +0300, Dan Carpenter wrote: > On Fri, Oct 04, 2019 at 10:53:44PM +0100, Colin Ian King wrote: > > On 04/10/2019 20:27, Liviu Dudau wrote: > > > On Fri, Oct 04, 2019 at 05:21:56PM +0100, Colin King wrote: > > >> From: Colin Ian King <colin.king@canonical.com> > > >> > > >> The pointer disable_done is being initialized with a value that > > >> is never read and is being re-assigned a little later on. The > > >> assignment is redundant and hence can be removed. > > > > > > Not really true, isn't it? The re-assignment is done under the condition that > > > crtc->state->active is true. disable_done will be used regardless after the if > > > block, so we can't skip this initialisation. > > > > > > Not sure why Coverity flags this, but I would NAK this patch. > > > > I'm patching against the driver from linux-next so I believe this is OK > > for that. I believe your statement is true against linux which does not > > have commit: > > > > d6cb013579e743bc7bc5590ca35a1943f2b8f3c8 > > Author: Lowry Li (Arm Technology China) <Lowry.Li@arm.com> > > Date: Fri Sep 6 07:18:06 2019 +0000 > > > > It really does help reviewing patches when this is mentioned in the > commit message. > > There is some debate about whether this should be mentioned as a Fixes > since it doesn't fix a bug. I initialy felt it shouldn't be, but now > I think enough people think it should be listed as Fixes that I must be > wrong. Either way, it's very useful information. > > The other thing is that soon get_maintainer.pl will start CC'ing people > from the Fixes tag and right now Lowry Li is not CC'd so that's > unfortunate. > > regards, > dan carpenter Hi Liviu: Colin's code is right. Following code I copied from linux-next, and I checked drm-misc, the code are same. struct komeda_pipeline *slave = kcrtc->slave; //---- First initialization. struct completion *disable_done = &crtc->state->commit->flip_done; bool needs_phase2 = false; DRM_DEBUG_ATOMIC("CRTC%d_DISABLE: active_pipes: 0x%x, affected: 0x%x\n", drm_crtc_index(crtc), old_st->active_pipes, old_st->affected_pipes); if (slave && has_bit(slave->id, old_st->active_pipes)) komeda_pipeline_disable(slave, old->state); if (has_bit(master->id, old_st->active_pipes)) needs_phase2 = komeda_pipeline_disable(master, old->state); //---- Secondary initialization. disable_done = (needs_phase2 || crtc->state->active) ? NULL : &crtc->state->commit->flip_done; //--- First using is here. /* wait phase 1 disable done */ komeda_crtc_flush_and_wait_for_flip_done(kcrtc, disable_done); So the first initialization with the delcaration is unnecessary. And I also checked our internal testing branch which actually doesn't have the first initialization. seems somethings wrong when lowry submit this to upstream. Hi Colin: Thanks for the fix. I'll push it to drm-misc-fixes Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com> Best Regards James
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c index 75263d8cd0bd..9beeda04818b 100644 --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c @@ -296,7 +296,7 @@ komeda_crtc_atomic_disable(struct drm_crtc *crtc, struct komeda_crtc_state *old_st = to_kcrtc_st(old); struct komeda_pipeline *master = kcrtc->master; struct komeda_pipeline *slave = kcrtc->slave; - struct completion *disable_done = &crtc->state->commit->flip_done; + struct completion *disable_done; bool needs_phase2 = false; DRM_DEBUG_ATOMIC("CRTC%d_DISABLE: active_pipes: 0x%x, affected: 0x%x\n",