| Message ID | 20190318131155.29450-3-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen: simplify suspend/resume handling | expand |
On Mon, 2019-03-18 at 14:11 +0100, Juergen Gross wrote: > Add a helper cpu_notifier_call_chain() to call notifier_call_chain() > for a cpu with a specified action, returning an errno value. > > This avoids coding the same pattern multiple times. > > Signed-off-by: Juergen Gross <jgross@suse.com> > Reviewed-by: Dario Faggioli <dfaggioli@suse.com> Regards, Dario
On 3/18/19 1:11 PM, Juergen Gross wrote: > Add a helper cpu_notifier_call_chain() to call notifier_call_chain() > for a cpu with a specified action, returning an errno value. > > This avoids coding the same pattern multiple times. > > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: George Dunlap <george.dunlap@citrix.com>
On 18/03/2019 13:11, Juergen Gross wrote: > Add a helper cpu_notifier_call_chain() to call notifier_call_chain() > for a cpu with a specified action, returning an errno value. > > This avoids coding the same pattern multiple times. > > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > xen/common/cpu.c | 50 +++++++++++++++++++++----------------------------- > 1 file changed, 21 insertions(+), 29 deletions(-) > > diff --git a/xen/common/cpu.c b/xen/common/cpu.c > index 836c62f97f..c436c0de7f 100644 > --- a/xen/common/cpu.c > +++ b/xen/common/cpu.c > @@ -71,11 +71,18 @@ void __init register_cpu_notifier(struct notifier_block *nb) > spin_unlock(&cpu_add_remove_lock); > } > > +static int cpu_notifier_call_chain(unsigned int cpu, unsigned long action, > + struct notifier_block **nb) > +{ > + void *hcpu = (void *)(long)cpu; > + int notifier_rc = notifier_call_chain(&cpu_chain, action, hcpu, nb); > + > + return (notifier_rc == NOTIFY_DONE) ? 0 : notifier_to_errno(notifier_rc); > +} > + > static void _take_cpu_down(void *unused) > { > - void *hcpu = (void *)(long)smp_processor_id(); > - int notifier_rc = notifier_call_chain(&cpu_chain, CPU_DYING, hcpu, NULL); > - BUG_ON(notifier_rc != NOTIFY_DONE); > + BUG_ON(cpu_notifier_call_chain(smp_processor_id(), CPU_DYING, NULL)); Where possible, we're trying to remove side effects from macros. Could I please talk you into writing this as: int rc = cpu_notifier_call_chain(smp_processor_id(), CPU_DYING, NULL); BUG_ON(rc); An alternative might be to have a: static void cpu_notifier_call_chain_nofail(...) wrapper as this seems to be a common pattern. (Ideally longterm, it might be better to pass the nofail intention into the notifier chain itself so we can identify which callback had a problem, but thats definitely not something for here.) ~Andrew
On 27/03/2019 16:39, Andrew Cooper wrote: > On 18/03/2019 13:11, Juergen Gross wrote: >> Add a helper cpu_notifier_call_chain() to call notifier_call_chain() >> for a cpu with a specified action, returning an errno value. >> >> This avoids coding the same pattern multiple times. >> >> Signed-off-by: Juergen Gross <jgross@suse.com> >> --- >> xen/common/cpu.c | 50 +++++++++++++++++++++----------------------------- >> 1 file changed, 21 insertions(+), 29 deletions(-) >> >> diff --git a/xen/common/cpu.c b/xen/common/cpu.c >> index 836c62f97f..c436c0de7f 100644 >> --- a/xen/common/cpu.c >> +++ b/xen/common/cpu.c >> @@ -71,11 +71,18 @@ void __init register_cpu_notifier(struct notifier_block *nb) >> spin_unlock(&cpu_add_remove_lock); >> } >> >> +static int cpu_notifier_call_chain(unsigned int cpu, unsigned long action, >> + struct notifier_block **nb) >> +{ >> + void *hcpu = (void *)(long)cpu; >> + int notifier_rc = notifier_call_chain(&cpu_chain, action, hcpu, nb); >> + >> + return (notifier_rc == NOTIFY_DONE) ? 0 : notifier_to_errno(notifier_rc); >> +} >> + >> static void _take_cpu_down(void *unused) >> { >> - void *hcpu = (void *)(long)smp_processor_id(); >> - int notifier_rc = notifier_call_chain(&cpu_chain, CPU_DYING, hcpu, NULL); >> - BUG_ON(notifier_rc != NOTIFY_DONE); >> + BUG_ON(cpu_notifier_call_chain(smp_processor_id(), CPU_DYING, NULL)); > > Where possible, we're trying to remove side effects from macros. > > Could I please talk you into writing this as: > > int rc = cpu_notifier_call_chain(smp_processor_id(), CPU_DYING, NULL); > > BUG_ON(rc); Fine with me. Juergen
diff --git a/xen/common/cpu.c b/xen/common/cpu.c index 836c62f97f..c436c0de7f 100644 --- a/xen/common/cpu.c +++ b/xen/common/cpu.c @@ -71,11 +71,18 @@ void __init register_cpu_notifier(struct notifier_block *nb) spin_unlock(&cpu_add_remove_lock); } +static int cpu_notifier_call_chain(unsigned int cpu, unsigned long action, + struct notifier_block **nb) +{ + void *hcpu = (void *)(long)cpu; + int notifier_rc = notifier_call_chain(&cpu_chain, action, hcpu, nb); + + return (notifier_rc == NOTIFY_DONE) ? 0 : notifier_to_errno(notifier_rc); +} + static void _take_cpu_down(void *unused) { - void *hcpu = (void *)(long)smp_processor_id(); - int notifier_rc = notifier_call_chain(&cpu_chain, CPU_DYING, hcpu, NULL); - BUG_ON(notifier_rc != NOTIFY_DONE); + BUG_ON(cpu_notifier_call_chain(smp_processor_id(), CPU_DYING, NULL)); __cpu_disable(); } @@ -87,8 +94,7 @@ static int take_cpu_down(void *arg) int cpu_down(unsigned int cpu) { - int err, notifier_rc; - void *hcpu = (void *)(long)cpu; + int err; struct notifier_block *nb = NULL; if ( !cpu_hotplug_begin() ) @@ -100,12 +106,9 @@ int cpu_down(unsigned int cpu) return -EINVAL; } - notifier_rc = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE, hcpu, &nb); - if ( notifier_rc != NOTIFY_DONE ) - { - err = notifier_to_errno(notifier_rc); + err = cpu_notifier_call_chain(cpu, CPU_DOWN_PREPARE, &nb); + if ( err ) goto fail; - } if ( unlikely(system_state < SYS_STATE_active) ) on_selected_cpus(cpumask_of(cpu), _take_cpu_down, NULL, true); @@ -115,24 +118,21 @@ int cpu_down(unsigned int cpu) __cpu_die(cpu); BUG_ON(cpu_online(cpu)); - notifier_rc = notifier_call_chain(&cpu_chain, CPU_DEAD, hcpu, NULL); - BUG_ON(notifier_rc != NOTIFY_DONE); + BUG_ON(cpu_notifier_call_chain(cpu, CPU_DEAD, NULL)); send_global_virq(VIRQ_PCPU_STATE); cpu_hotplug_done(); return 0; fail: - notifier_rc = notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED, hcpu, &nb); - BUG_ON(notifier_rc != NOTIFY_DONE); + BUG_ON(cpu_notifier_call_chain(cpu, CPU_DOWN_FAILED, &nb)); cpu_hotplug_done(); return err; } int cpu_up(unsigned int cpu) { - int notifier_rc, err = 0; - void *hcpu = (void *)(long)cpu; + int err; struct notifier_block *nb = NULL; if ( !cpu_hotplug_begin() ) @@ -144,19 +144,15 @@ int cpu_up(unsigned int cpu) return -EINVAL; } - notifier_rc = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu, &nb); - if ( notifier_rc != NOTIFY_DONE ) - { - err = notifier_to_errno(notifier_rc); + err = cpu_notifier_call_chain(cpu, CPU_UP_PREPARE, &nb); + if ( err ) goto fail; - } err = __cpu_up(cpu); if ( err < 0 ) goto fail; - notifier_rc = notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu, NULL); - BUG_ON(notifier_rc != NOTIFY_DONE); + BUG_ON(cpu_notifier_call_chain(cpu, CPU_ONLINE, NULL)); send_global_virq(VIRQ_PCPU_STATE); @@ -164,18 +160,14 @@ int cpu_up(unsigned int cpu) return 0; fail: - notifier_rc = notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu, &nb); - BUG_ON(notifier_rc != NOTIFY_DONE); + BUG_ON(cpu_notifier_call_chain(cpu, CPU_UP_CANCELED, &nb)); cpu_hotplug_done(); return err; } void notify_cpu_starting(unsigned int cpu) { - void *hcpu = (void *)(long)cpu; - int notifier_rc = notifier_call_chain( - &cpu_chain, CPU_STARTING, hcpu, NULL); - BUG_ON(notifier_rc != NOTIFY_DONE); + BUG_ON(cpu_notifier_call_chain(cpu, CPU_STARTING, NULL)); } static cpumask_t frozen_cpus;
Add a helper cpu_notifier_call_chain() to call notifier_call_chain() for a cpu with a specified action, returning an errno value. This avoids coding the same pattern multiple times. Signed-off-by: Juergen Gross <jgross@suse.com> --- xen/common/cpu.c | 50 +++++++++++++++++++++----------------------------- 1 file changed, 21 insertions(+), 29 deletions(-)