LinuxPPC-Dev Archive on lore.kernel.org
 help / color / Atom feed
From: Sourabh Jain <sourabhjain@linux.ibm.com>
To: "Michal Suchánek" <msuchanek@suse.de>
Cc: linux-doc@vger.kernel.org, mahesh@linux.vnet.ibm.com,
	corbet@lwn.net, linux-kernel@vger.kernel.org,
	linuxppc-dev@ozlabs.org, hbathini@linux.ibm.com
Subject: Re: [PATCH v3 2/4] powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files
Date: Sat, 16 Nov 2019 20:07:29 +0530
Message-ID: <8c1ec297-0c34-12de-2528-be436697215a@linux.ibm.com> (raw)
In-Reply-To: <20191109125933.GF1384@kitsune.suse.cz>



On 11/9/19 6:29 PM, Michal Suchánek wrote:
> On Sat, Nov 09, 2019 at 05:53:37PM +0530, Sourabh Jain wrote:
>> As the number of FADump sysfs files increases it is hard to manage all of
>> them inside /sys/kernel directory. It's better to have all the FADump
>> related sysfs files in a dedicated directory /sys/kernel/fadump. But in
>> order to maintain the backward compatibility the /sys/kernel/fadump_*
>> sysfs files are replicated inside /sys/kernel/fadump/ and eventually get
>> removed in future.
>>
>> As the FADump sysfs files are now part of dedicated directory there is no
>> need to prefix their name with fadump_, hence sysfs file names are also
>> updated. For example fadump_enabled sysfs file is now referred as enabled.
>>
>> Also consolidate ABI documentation for all the FADump sysfs files in a
>> single file Documentation/ABI/testing/sysfs-kernel-fadump.
>>
>> Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
>> ---
>>  Documentation/ABI/testing/sysfs-kernel-fadump | 41 +++++++++++++++++++
>>  arch/powerpc/kernel/fadump.c                  | 38 +++++++++++++++++
>>  arch/powerpc/platforms/powernv/opal-core.c    | 10 +++--
>>  3 files changed, 86 insertions(+), 3 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump
>>
>> diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump
>> new file mode 100644
>> index 000000000000..a77f1a5ba389
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
>> @@ -0,0 +1,41 @@
>> +What:		/sys/kernel/fadump/*
>> +Date:		Nov 2019
>> +Contact:	linuxppc-dev@lists.ozlabs.org
>> +Description:
>> +		The /sys/kernel/fadump/* is a collection of FADump sysfs
>> +		file provide information about the configuration status
>> +		of Firmware Assisted Dump (FADump).
>> +
>> +What:		/sys/kernel/fadump/enabled
>> +Date:		Nov 2019
>> +Contact:	linuxppc-dev@lists.ozlabs.org
>> +Description:	read only
>> +		Primarily used to identify whether the FADump is enabled in
>> +		the kernel or not.
>> +User:		Kdump service
>> +
>> +What:		/sys/kernel/fadump/registered
>> +Date:		Nov 2019
>> +Contact:	linuxppc-dev@lists.ozlabs.org
>> +Description:	read/write
>> +		Helps to control the dump collect feature from userspace.
>> +		Setting 1 to this file enables the system to collect the
>> +		dump and 0 to disable it.
>> +User:		Kdump service
>> +
>> +What:		/sys/kernel/fadump/release_mem
>> +Date:		Nov 2019
>> +Contact:	linuxppc-dev@lists.ozlabs.org
>> +Description:	write only
>> +		This is a special sysfs file and only available when
>> +		the system is booted to capture the vmcore using FADump.
>> +		It is used to release the memory reserved by FADump to
>> +		save the crash dump.
>> +
>> +What:		/sys/kernel/fadump/release_opalcore
>> +Date:		Nov 2019
>> +Contact:	linuxppc-dev@lists.ozlabs.org
>> +Description:	write only
>> +		The sysfs file is available when the system is booted to
>> +		collect the dump on OPAL based machine. It used to release
>> +		the memory used to collect the opalcore.
>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
>> index ed59855430b9..a9591def0c84 100644
>> --- a/arch/powerpc/kernel/fadump.c
>> +++ b/arch/powerpc/kernel/fadump.c
>> @@ -1418,6 +1418,9 @@ static int fadump_region_show(struct seq_file *m, void *private)
>>  	return 0;
>>  }
>>  
>> +struct kobject *fadump_kobj;
>> +EXPORT_SYMBOL_GPL(fadump_kobj);
>> +
>>  static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
>>  						0200, NULL,
>>  						fadump_release_memory_store);
>> @@ -1428,6 +1431,16 @@ static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
>>  						0644, fadump_register_show,
>>  						fadump_register_store);
>>  
>> +static struct kobj_attribute release_attr = __ATTR(release_mem,
>> +						0200, NULL,
>> +						fadump_release_memory_store);
>> +static struct kobj_attribute enable_attr = __ATTR(enabled,
>> +						0444, fadump_enabled_show,
>> +						NULL);
>> +static struct kobj_attribute register_attr = __ATTR(registered,
>> +						0644, fadump_register_show,
>> +						fadump_register_store);
>> +
>>  DEFINE_SHOW_ATTRIBUTE(fadump_region);
>>  
>>  static void fadump_init_files(void)
>> @@ -1435,6 +1448,11 @@ static void fadump_init_files(void)
>>  	struct dentry *debugfs_file;
>>  	int rc = 0;
>>  
>> +	fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
>> +	if (!fadump_kobj) {
>> +		pr_err("failed to create fadump kobject\n");
>> +		return;
>> +	}
>>  	rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
>>  	if (rc)
>>  		printk(KERN_ERR "fadump: unable to create sysfs file"
>> @@ -1458,6 +1476,26 @@ static void fadump_init_files(void)
>>  			printk(KERN_ERR "fadump: unable to create sysfs file"
>>  				" fadump_release_mem (%d)\n", rc);
>>  	}
>> +	/* Replicating the following sysfs attributes under FADump kobject.
>> +	 *
>> +	 *	- fadump_enabled -> enabled
>> +	 *	- fadump_registered -> registered
>> +	 *	- fadump_release_mem -> release_mem
>> +	 */
>> +	rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
>> +	if (rc)
>> +		pr_err("unable to create enabled sysfs file (%d)\n",
>> +		       rc);
>> +	rc = sysfs_create_file(fadump_kobj, &register_attr.attr);
>> +	if (rc)
>> +		pr_err("unable to create registered sysfs file (%d)\n",
>> +		       rc);
>> +	if (fw_dump.dump_active) {
>> +		rc = sysfs_create_file(fadump_kobj, &release_attr.attr);
>> +		if (rc)
>> +			pr_err("unable to create release_mem sysfs file (%d)\n",
>> +			       rc);
>> +	}
>>  	return;
>>  }
> Hello,
> 

I’m so sorry for taking this long to write you back. 

> wouldn't it make more sense to create the files in the new location and
> add a symlink at the old location?

There are APIs which allow to create a symlink for an entire kobject but
I did not find a way to create symlink of an individual sysfs file.

Do you have any approach in mind to achieve the same?


> Also your error messages aren't really readeable. Without the fadump_
> prefix it's not clear what's going on here. Perhaps quoting the file
> name and saying fadump somewhere in the message would be useful.

The pr_err function will prefix the error message with fadump: string.
I think that will solve the above issue.


Thanks,

Sourabh Jain


  reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-09 12:23 [PATCH v3 0/4] reorganize and add FADump " Sourabh Jain
2019-11-09 12:23 ` [PATCH v3 1/4] Documentation/ABI: add ABI documentation for /sys/kernel/fadump_* Sourabh Jain
2019-11-09 12:23 ` [PATCH v3 2/4] powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files Sourabh Jain
2019-11-09 12:59   ` Michal Suchánek
2019-11-16 14:37     ` Sourabh Jain [this message]
2019-11-24 18:40       ` Michal Suchánek
2019-11-27  4:54         ` Sourabh Jain
2019-12-03 11:20         ` Sourabh Jain
2019-11-23 11:21   ` kbuild test robot
2019-11-09 12:23 ` [PATCH v3 3/4] Documentation/ABI: mark /sys/kernel/fadump_* sysfs files deprecated Sourabh Jain
2019-11-09 12:23 ` [PATCH v3 4/4] powerpc/fadump: sysfs for fadump memory reservation Sourabh Jain

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=8c1ec297-0c34-12de-2528-be436697215a@linux.ibm.com \
    --to=sourabhjain@linux.ibm.com \
    --cc=corbet@lwn.net \
    --cc=hbathini@linux.ibm.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.org \
    --cc=mahesh@linux.vnet.ibm.com \
    --cc=msuchanek@suse.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LinuxPPC-Dev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linuxppc-dev/0 linuxppc-dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linuxppc-dev linuxppc-dev/ https://lore.kernel.org/linuxppc-dev \
		linuxppc-dev@lists.ozlabs.org linuxppc-dev@ozlabs.org
	public-inbox-index linuxppc-dev

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.ozlabs.lists.linuxppc-dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git