| Message ID | 1444480254-14399-6-git-send-email-Julia.Lawall@lip6.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Saturday 10 October 2015 14:30:54 Julia Lawall wrote: > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > index 11c54de..432ff34 100644 > --- a/arch/arm/kernel/devtree.c > +++ b/arch/arm/kernel/devtree.c > @@ -143,6 +143,7 @@ void __init arm_dt_init_cpu_maps(void) > "max cores %u, capping them\n", > cpuidx, nr_cpu_ids)) { > cpuidx = nr_cpu_ids; > + of_node_put(cpu); > break; > } > The same for_each_child_of_node() loop has three 'return' statements' aside from the 'break' statement here. I think you should change your semantic patch to cover both cases. Arnd
Arnd, On Sat, 10 Oct 2015 23:02:15 +0200, Arnd Bergmann wrote: > The same for_each_child_of_node() loop has three 'return' statements' > aside from the 'break' statement here. I think you should change your > semantic patch to cover both cases. I think Julia's semantic patch covers both cases, but only the cases where there is one break or return (though I have essentially zero Coccinelle knowledge, this is all based on guessing looking at the semantic patch in the cover letter). Thomas
On Sat, 10 Oct 2015, Arnd Bergmann wrote: > On Saturday 10 October 2015 14:30:54 Julia Lawall wrote: > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > > index 11c54de..432ff34 100644 > > --- a/arch/arm/kernel/devtree.c > > +++ b/arch/arm/kernel/devtree.c > > @@ -143,6 +143,7 @@ void __init arm_dt_init_cpu_maps(void) > > "max cores %u, capping them\n", > > cpuidx, nr_cpu_ids)) { > > cpuidx = nr_cpu_ids; > > + of_node_put(cpu); > > break; > > } > > > > The same for_each_child_of_node() loop has three 'return' statements' > aside from the 'break' statement here. I think you should change your > semantic patch to cover both cases. It was intended to, but it seems that it's not working on the case where there is no argument to return. In any case, it's an opportunity to ask a question. Would one want a of_node_put in front of every return, or should the returns become gotos, to a single of_node_put after the current end of the function? julia
On Sat, 10 Oct 2015, Thomas Petazzoni wrote: > Arnd, > > On Sat, 10 Oct 2015 23:02:15 +0200, Arnd Bergmann wrote: > > > The same for_each_child_of_node() loop has three 'return' statements' > > aside from the 'break' statement here. I think you should change your > > semantic patch to cover both cases. > > I think Julia's semantic patch covers both cases, but only the cases > where there is one break or return (though I have essentially zero > Coccinelle knowledge, this is all based on guessing looking at the > semantic patch in the cover letter). Normally, it should be OK with lots of returns. And contrary to my previous email, even with return;. Will check on it. julia
On Saturday 10 October 2015 23:10:06 Julia Lawall wrote: > On Sat, 10 Oct 2015, Arnd Bergmann wrote: > > > On Saturday 10 October 2015 14:30:54 Julia Lawall wrote: > > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > > > index 11c54de..432ff34 100644 > > > --- a/arch/arm/kernel/devtree.c > > > +++ b/arch/arm/kernel/devtree.c > > > @@ -143,6 +143,7 @@ void __init arm_dt_init_cpu_maps(void) > > > "max cores %u, capping them\n", > > > cpuidx, nr_cpu_ids)) { > > > cpuidx = nr_cpu_ids; > > > + of_node_put(cpu); > > > break; > > > } > > > > > > > The same for_each_child_of_node() loop has three 'return' statements' > > aside from the 'break' statement here. I think you should change your > > semantic patch to cover both cases. > > It was intended to, Ok, I saw that just after replying... > but it seems that it's not working on the case where > there is no argument to return. > In any case, it's an opportunity to ask a question. Would one want a > of_node_put in front of every return, or should the returns become gotos, > to a single of_node_put after the current end of the function? The two styles that I see in code I consider particularly clean are: - have only one return statement in the function and use goto for error handling - avoid the goto and have the early return. Mixing the two tends to make the function less readable, so I'd only change it to use gotos if it can be done nicely for all cases. Arnd
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c index 11c54de..432ff34 100644 --- a/arch/arm/kernel/devtree.c +++ b/arch/arm/kernel/devtree.c @@ -143,6 +143,7 @@ void __init arm_dt_init_cpu_maps(void) "max cores %u, capping them\n", cpuidx, nr_cpu_ids)) { cpuidx = nr_cpu_ids; + of_node_put(cpu); break; }
for_each_child_of_node performs an of_node_get on each iteration, so a break out of the loop requires an of_node_put. The semantic patch that fixes this problem is as follows (http://coccinelle.lip6.fr): // <smpl> @@ expression root,e; local idexpression child; iterator name for_each_child_of_node; @@ for_each_child_of_node(root, child) { ... when != of_node_put(child) when != e = child + of_node_put(child); ? break; ... } ... when != child // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> --- arch/arm/kernel/devtree.c | 1 + 1 file changed, 1 insertion(+)