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Message-ID: <87f6365f-a40e-4606-baff-170cb8fc48f3@infradead.org>
Date: Fri, 22 Mar 2024 17:34:45 +0900
From: Geoff Levand <geoff@...radead.org>
To: Geert Uytterhoeven <geert@...ux-m68k.org>, Arnd Bergmann <arnd@...nel.org>
Cc: Michael Ellerman <mpe@...erman.id.au>,
Nathan Chancellor <nathan@...nel.org>, Paul Mackerras <paulus@...abs.org>,
Arnd Bergmann <arnd@...db.de>, Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
"Aneesh Kumar K.V" <aneesh.kumar@...nel.org>,
"Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>,
Nick Desaulniers <ndesaulniers@...gle.com>, Bill Wendling
<morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>,
Kevin Hao <haokexin@...il.com>, linuxppc-dev@...ts.ozlabs.org,
linux-kernel@...r.kernel.org, llvm@...ts.linux.dev
Subject: Re: [PATCH] powerpc: ps3: mark ps3_notification_device static for
stack usage
On 3/21/24 17:32, Geert Uytterhoeven wrote:
> --- a/arch/powerpc/platforms/ps3/device-init.c
>> +++ b/arch/powerpc/platforms/ps3/device-init.c
>> @@ -770,7 +770,7 @@ static struct task_struct *probe_task;
>>
>> static int ps3_probe_thread(void *data)
>> {
>> - struct ps3_notification_device dev;
>> + static struct ps3_notification_device dev;
>> int res;
>> unsigned int irq;
>> u64 lpar;
>
> Making it static increases kernel size for everyone. So I'd rather
> allocate it dynamically. The thread already allocates a buffer, which
> can be replaced at no cost by allocating a structure containing both
> the ps3_notification_device and the buffer.
Here's what I came up with. It builds for me without warnings.
I haven't tested it yet. A review would be appreciated.
diff --git a/arch/powerpc/platforms/ps3/device-init.c b/arch/powerpc/platforms/ps3/device-init.c
index 878bc160246e..9bb44a6ccdaf 100644
--- a/arch/powerpc/platforms/ps3/device-init.c
+++ b/arch/powerpc/platforms/ps3/device-init.c
@@ -770,37 +770,48 @@ static struct task_struct *probe_task;
static int ps3_probe_thread(void *data)
{
- struct ps3_notification_device dev;
+ struct ps3_probe_thread_local {
+ struct ps3_notification_device dev;
+ union {
+ char buf[512];
+ struct ps3_notify_cmd notify_cmd;
+ struct ps3_notify_event notify_event;
+ };
+ };
+ struct ps3_probe_thread_local *local;
+ struct ps3_notification_device *dev;
+ struct ps3_notify_cmd *notify_cmd;
+ struct ps3_notify_event *notify_event;
int res;
unsigned int irq;
u64 lpar;
- void *buf;
- struct ps3_notify_cmd *notify_cmd;
- struct ps3_notify_event *notify_event;
pr_debug(" -> %s:%u: kthread started\n", __func__, __LINE__);
- buf = kzalloc(512, GFP_KERNEL);
- if (!buf)
+ local = kzalloc(sizeof(local), GFP_KERNEL);
+
+ if (!local)
return -ENOMEM;
- lpar = ps3_mm_phys_to_lpar(__pa(buf));
- notify_cmd = buf;
- notify_event = buf;
+ dev = &local->dev;
+ notify_cmd = &local->notify_cmd;
+ notify_event = &local->notify_event;
+
+ lpar = ps3_mm_phys_to_lpar(__pa(&local->notify_cmd));
/* dummy system bus device */
- dev.sbd.bus_id = (u64)data;
- dev.sbd.dev_id = PS3_NOTIFICATION_DEV_ID;
- dev.sbd.interrupt_id = PS3_NOTIFICATION_INTERRUPT_ID;
+ dev->sbd.bus_id = (u64)data;
+ dev->sbd.dev_id = PS3_NOTIFICATION_DEV_ID;
+ dev->sbd.interrupt_id = PS3_NOTIFICATION_INTERRUPT_ID;
- res = lv1_open_device(dev.sbd.bus_id, dev.sbd.dev_id, 0);
+ res = lv1_open_device(dev->sbd.bus_id, dev->sbd.dev_id, 0);
if (res) {
pr_err("%s:%u: lv1_open_device failed %s\n", __func__,
__LINE__, ps3_result(res));
goto fail_free;
}
- res = ps3_sb_event_receive_port_setup(&dev.sbd, PS3_BINDING_CPU_ANY,
+ res = ps3_sb_event_receive_port_setup(&dev->sbd, PS3_BINDING_CPU_ANY,
&irq);
if (res) {
pr_err("%s:%u: ps3_sb_event_receive_port_setup failed %d\n",
@@ -808,11 +819,11 @@ static int ps3_probe_thread(void *data)
goto fail_close_device;
}
- spin_lock_init(&dev.lock);
- rcuwait_init(&dev.wait);
+ spin_lock_init(&dev->lock);
+ rcuwait_init(&dev->wait);
res = request_irq(irq, ps3_notification_interrupt, 0,
- "ps3_notification", &dev);
+ "ps3_notification", &local->dev);
if (res) {
pr_err("%s:%u: request_irq failed %d\n", __func__, __LINE__,
res);
@@ -823,7 +834,7 @@ static int ps3_probe_thread(void *data)
notify_cmd->operation_code = 0; /* must be zero */
notify_cmd->event_mask = 1UL << notify_region_probe;
- res = ps3_notification_read_write(&dev, lpar, 1);
+ res = ps3_notification_read_write(&local->dev, lpar, 1);
if (res)
goto fail_free_irq;
@@ -834,36 +845,36 @@ static int ps3_probe_thread(void *data)
memset(notify_event, 0, sizeof(*notify_event));
- res = ps3_notification_read_write(&dev, lpar, 0);
+ res = ps3_notification_read_write(&local->dev, lpar, 0);
if (res)
break;
pr_debug("%s:%u: notify event type 0x%llx bus id %llu dev id %llu"
" type %llu port %llu\n", __func__, __LINE__,
- notify_event->event_type, notify_event->bus_id,
- notify_event->dev_id, notify_event->dev_type,
- notify_event->dev_port);
+ notify_event->event_type, notify_event->bus_id,
+ notify_event->dev_id, notify_event->dev_type,
+ notify_event->dev_port);
if (notify_event->event_type != notify_region_probe ||
- notify_event->bus_id != dev.sbd.bus_id) {
+ notify_event->bus_id != dev->sbd.bus_id) {
pr_warn("%s:%u: bad notify_event: event %llu, dev_id %llu, dev_type %llu\n",
__func__, __LINE__, notify_event->event_type,
notify_event->dev_id, notify_event->dev_type);
continue;
}
- ps3_find_and_add_device(dev.sbd.bus_id, notify_event->dev_id);
+ ps3_find_and_add_device(dev->sbd.bus_id, notify_event->dev_id);
} while (!kthread_should_stop());
fail_free_irq:
- free_irq(irq, &dev);
+ free_irq(irq, &local->dev);
fail_sb_event_receive_port_destroy:
- ps3_sb_event_receive_port_destroy(&dev.sbd, irq);
+ ps3_sb_event_receive_port_destroy(&dev->sbd, irq);
fail_close_device:
- lv1_close_device(dev.sbd.bus_id, dev.sbd.dev_id);
+ lv1_close_device(dev->sbd.bus_id, dev->sbd.dev_id);
fail_free:
- kfree(buf);
+ kfree(local);
probe_task = NULL;
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