Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/4] oprofile: Handle initialisation failure more gracefully | From | Will Deacon <> | Date | Fri, 27 Aug 2010 19:06:45 +0100 |
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Hi Robert,
Thanks for taking the time to look at this.
On Fri, 2010-08-27 at 17:38 +0100, Robert Richter wrote: > On 27.08.10 11:15:25, Will Deacon wrote:
> > How about something like this? This removes the exit call > > from the init code and sets pointers to NULL after they have been > > freed. We still have to do some checking so that we don't try to > > release a NULL perf event: > > > > diff --git a/arch/arm/oprofile/common.c b/arch/arm/oprofile/common.c > > index 0691176..12253eb 100644 > > --- a/arch/arm/oprofile/common.c > > +++ b/arch/arm/oprofile/common.c > > @@ -275,10 +275,12 @@ out: > > return ret; > > } > > > > -static void exit_driverfs(void) > > +static void __exit exit_driverfs(void) > > { > > - platform_device_unregister(oprofile_pdev); > > - platform_driver_unregister(&oprofile_driver); > > + if (!IS_ERR_OR_NULL(oprofile_pdev)) { > > This check is obsolete here as we do not call oprofile_arch_exit() on > failure. > Sorry, I was being braindead and thought oprofile_arch_exit might be called via oprofile_exit. As it happens, this is only called because of module_exit so we know that initialisation will have completed.
In light of this and your comments, I've simplified the code. Once people are happy with it, I'll post it as a couple of patches:
diff --git a/arch/arm/oprofile/common.c b/arch/arm/oprofile/common.c index 0691176..c2c4a2e 100644 --- a/arch/arm/oprofile/common.c +++ b/arch/arm/oprofile/common.c @@ -275,7 +275,7 @@ out: return ret; } -static void exit_driverfs(void) +static void __exit exit_driverfs(void) { platform_device_unregister(oprofile_pdev); platform_driver_unregister(&oprofile_driver); @@ -359,14 +359,13 @@ int __init oprofile_arch_init(struct oprofile_operations *ops) if (!counter_config) { pr_info("oprofile: failed to allocate %d " "counters\n", perf_num_counters); - return -ENOMEM; + ret = -ENOMEM; + goto out; } ret = init_driverfs(); - if (ret) { - kfree(counter_config); - return ret; - } + if (ret) + goto out; for_each_possible_cpu(cpu) { perf_events[cpu] = kcalloc(perf_num_counters, @@ -374,9 +373,8 @@ int __init oprofile_arch_init(struct oprofile_operations *ops) if (!perf_events[cpu]) { pr_info("oprofile: failed to allocate %d perf events " "for cpu %d\n", perf_num_counters, cpu); - while (--cpu >= 0) - kfree(perf_events[cpu]); - return -ENOMEM; + ret = -ENOMEM; + goto out; } } @@ -393,28 +391,33 @@ int __init oprofile_arch_init(struct oprofile_operations *ops) else pr_info("oprofile: using %s\n", ops->cpu_type); +out: + if (ret) { + kfree(counter_config); + for_each_possible_cpu(cpu) + kfree(perf_events[cpu]); + } + return ret; } -void oprofile_arch_exit(void) +void __exit oprofile_arch_exit(void) { int cpu, id; struct perf_event *event; - if (*perf_events) { - exit_driverfs(); - for_each_possible_cpu(cpu) { - for (id = 0; id < perf_num_counters; ++id) { - event = perf_events[cpu][id]; - if (event != NULL) - perf_event_release_kernel(event); - } - kfree(perf_events[cpu]); + for_each_possible_cpu(cpu) { + for (id = 0; id < perf_num_counters; ++id) { + event = perf_events[cpu][id]; + if (event) + perf_event_release_kernel(event); } + + kfree(perf_events[cpu]); } - if (counter_config) - kfree(counter_config); + kfree(counter_config); + exit_driverfs(); } #else int __init oprofile_arch_init(struct oprofile_operations *ops) @@ -422,5 +425,5 @@ int __init oprofile_arch_init(struct oprofile_operations *ops) pr_info("oprofile: hardware counters not available\n"); return -ENODEV; } -void oprofile_arch_exit(void) {} +void __exit oprofile_arch_exit(void) {} #endif /* CONFIG_HW_PERF_EVENTS */ diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c index b336cd9..b4a6857 100644 --- a/drivers/oprofile/oprof.c +++ b/drivers/oprofile/oprof.c @@ -257,16 +257,9 @@ static int __init oprofile_init(void) printk(KERN_INFO "oprofile: using timer interrupt.\n"); err = oprofile_timer_init(&oprofile_ops); if (err) - goto out_arch; + return err; } - err = oprofilefs_register(); - if (err) - goto out_arch; - return 0; - -out_arch: - oprofile_arch_exit(); - return err; + return oprofilefs_register(); }
Once again, thanks for looking at this and have a good weekend, Will
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