Re: [PATCH v17 2/6] crash: add a new kexec flag for hotplug support

From: Sourabh Jain <sourabhjain@linux.ibm.com>
To: Baoquan He <bhe@redhat.com>
Cc: linuxppc-dev@ozlabs.org, Akhil Raj <lf32.dev@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Aneesh Kumar K . V" <aneesh.kumar@kernel.org>,
	Borislav Petkov <bp@alien8.de>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Dave Young <dyoung@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Eric DeVolder <eric.devolder@oracle.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Hari Bathini <hbathini@linux.ibm.com>,
	Laurent Dufour <laurent.dufour@fr.ibm.com>,
	Mahesh Salgaonkar <mahesh@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Mimi Zohar <zohar@linux.ibm.com>,
	Naveen N Rao <naveen@kernel.org>,
	Oscar Salvador <osalvador@suse.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Valentin Schneider <vschneid@redhat.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	kexec@lists.infradead.org, x86@kernel.org
Subject: Re: [PATCH v17 2/6] crash: add a new kexec flag for hotplug support
Date: Thu, 29 Feb 2024 14:04:19 +0530	[thread overview]
Message-ID: <842e1f63-2586-49e9-8def-fae48160b67b@linux.ibm.com> (raw)
In-Reply-To: <ZeAyKj5b2HN90ija@MiWiFi-R3L-srv>

Hello

On 29/02/24 12:58, Baoquan He wrote:
> On 02/26/24 at 02:11pm, Sourabh Jain wrote:
> ......snip...
>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>> index 70fa8111a9d6..630c4fd7ea39 100644
>> --- a/kernel/crash_core.c
>> +++ b/kernel/crash_core.c
>> @@ -496,7 +496,7 @@ static DEFINE_MUTEX(__crash_hotplug_lock);
>>    * It reflects the kernel's ability/permission to update the crash
>>    * elfcorehdr directly.
>       ~~~~~~~~~ this should be updated too.
>
>>    */
>> -int crash_check_update_elfcorehdr(void)
>> +int crash_check_hotplug_support(void)
>>   {
>>   	int rc = 0;
>>   
>> @@ -508,10 +508,7 @@ int crash_check_update_elfcorehdr(void)
>>   		return 0;
>>   	}
>>   	if (kexec_crash_image) {
>> -		if (kexec_crash_image->file_mode)
>> -			rc = 1;
>> -		else
>> -			rc = kexec_crash_image->update_elfcorehdr;
>> +		rc = kexec_crash_image->hotplug_support;
>>   	}
>>   	/* Release lock now that update complete */
>>   	kexec_unlock();
>> @@ -552,8 +549,8 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu,
>>   
>>   	image = kexec_crash_image;
>>   
>> -	/* Check that updating elfcorehdr is permitted */
>> -	if (!(image->file_mode || image->update_elfcorehdr))
>> +	/* Check that kexec segments update is permitted */
>> +	if (!image->hotplug_support)
>>   		goto out;
>>   
>>   	if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
>> diff --git a/kernel/kexec.c b/kernel/kexec.c
>> index bab542fc1463..a6b3f96bb50c 100644
>> --- a/kernel/kexec.c
>> +++ b/kernel/kexec.c
>> @@ -135,8 +135,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
>>   		image->preserve_context = 1;
>>   
>>   #ifdef CONFIG_CRASH_HOTPLUG
>> -	if (flags & KEXEC_UPDATE_ELFCOREHDR)
>> -		image->update_elfcorehdr = 1;
>> +	if ((flags & KEXEC_ON_CRASH) && arch_crash_hotplug_support(image, flags))
>> +		image->hotplug_support = 1;
>>   #endif
>>   
>>   	ret = machine_kexec_prepare(image);
>> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>> index 2d1db05fbf04..3d64290d24c9 100644
>> --- a/kernel/kexec_file.c
>> +++ b/kernel/kexec_file.c
>> @@ -376,6 +376,11 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
>>   	if (ret)
>>   		goto out;
>>   
>> +#ifdef CONFIG_CRASH_HOTPLUG
>> +	if ((flags & KEXEC_FILE_ON_CRASH) && arch_crash_hotplug_support(image, flags))
>> +		image->hotplug_support = 1;
>> +#endif
>> +
>>   	ret = machine_kexec_prepare(image);
>>   	if (ret)
>>   		goto out;
> Other than the tiny part, the overall looks good to me.
>
> Acked-by: Baoquan He <bhe@redhat.com>
>

Thank you for the review and feedback.

- Sourabh

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