Re: [PATCH v4 3/6] powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files

2019-12-06 Thread Sourabh Jain



On 12/6/19 6:15 PM, Greg KH wrote:
> On Fri, Dec 06, 2019 at 05:54:31PM +0530, Sourabh Jain wrote:
>> +static struct kobj_attribute release_attr = __ATTR(release_mem,
>>  0200, NULL,
>>  fadump_release_memory_store);
>> -static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
>> +static struct kobj_attribute enable_attr = __ATTR(enabled,
>>  0444, fadump_enabled_show,
>>  NULL);
> 
> __ATTR_RO()?
> 
>> -static struct kobj_attribute fadump_register_attr = 
>> __ATTR(fadump_registered,
>> +static struct kobj_attribute register_attr = __ATTR(registered,
>>  0644, fadump_register_show,
>>  fadump_register_store);
> 
> __ATTR_RW()?

Thanks I was not aware of these macros.

> 
> And then use an ATTRIBUTE_GROUP() macro to create a group so that you
> then can do:
> 
>> @@ -1452,11 +1450,47 @@ static void fadump_init_files(void)
>>  printk(KERN_ERR "fadump: unable to create debugfs file"
>>  " fadump_region\n");
>>  
>> +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, ®ister_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);
>> +}
> 
> a single call to sysfs_create_groups() here instead of trying to unwind
> the mess if something went wrong.
> 

Sure, I will replace the individual calls with a single group call.

Thanks,
Sourabh Jain



Re: [PATCH v4 3/6] powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files

2019-12-06 Thread Greg KH
On Fri, Dec 06, 2019 at 05:54:31PM +0530, Sourabh Jain wrote:
> +static struct kobj_attribute release_attr = __ATTR(release_mem,
>   0200, NULL,
>   fadump_release_memory_store);
> -static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
> +static struct kobj_attribute enable_attr = __ATTR(enabled,
>   0444, fadump_enabled_show,
>   NULL);

__ATTR_RO()?

> -static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
> +static struct kobj_attribute register_attr = __ATTR(registered,
>   0644, fadump_register_show,
>   fadump_register_store);

__ATTR_RW()?

And then use an ATTRIBUTE_GROUP() macro to create a group so that you
then can do:

> @@ -1452,11 +1450,47 @@ static void fadump_init_files(void)
>   printk(KERN_ERR "fadump: unable to create debugfs file"
>   " fadump_region\n");
>  
> + 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, ®ister_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);
> + }

a single call to sysfs_create_groups() here instead of trying to unwind
the mess if something went wrong.

thanks,

greg k-h


[PATCH v4 3/6] powerpc/fadump: reorganize /sys/kernel/fadump_* sysfs files

2019-12-06 Thread Sourabh Jain
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 backward compatibility a symlink has been added for every
sysfs that has moved to new location.

As the FADump sysfs files are now part of a 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 
---
 Documentation/ABI/testing/sysfs-kernel-fadump | 33 ++
 arch/powerpc/kernel/fadump.c  | 66 ++-
 2 files changed, 83 insertions(+), 16 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 ..5d988b919e81
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump
@@ -0,0 +1,33 @@
+What:  /sys/kernel/fadump/*
+Date:  Dec 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:  Dec 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:  Dec 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:  Dec 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.
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index ed59855430b9..41a3cda81791 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1418,13 +1418,16 @@ static int fadump_region_show(struct seq_file *m, void 
*private)
return 0;
 }
 
-static struct kobj_attribute fadump_release_attr = __ATTR(fadump_release_mem,
+struct kobject *fadump_kobj;
+EXPORT_SYMBOL_GPL(fadump_kobj);
+
+static struct kobj_attribute release_attr = __ATTR(release_mem,
0200, NULL,
fadump_release_memory_store);
-static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
+static struct kobj_attribute enable_attr = __ATTR(enabled,
0444, fadump_enabled_show,
NULL);
-static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
+static struct kobj_attribute register_attr = __ATTR(registered,
0644, fadump_register_show,
fadump_register_store);
 
@@ -1435,16 +1438,11 @@ static void fadump_init_files(void)
struct dentry *debugfs_file;
int rc = 0;
 
-   rc = sysfs_create_file(kernel_kobj, &fadump_attr.attr);
-   if (rc)
-   printk(KERN_ERR "fadump: unable to create sysfs file"
-   " fadump_enabled (%d)\n", rc);
-
-   rc = sysfs_create_file(kernel_kobj, &fadump_register_attr.attr);
-   if (rc)
-   printk(KERN_ERR "fadump: unable to create sysfs file"
-   " fadump_registered (%d)\n", rc);
-
+   fadump_kobj = kobject_create_and_add("fadump", kernel_kobj);
+   if (!fadump_kobj) {
+   pr_err("failed to create fadump kobject\n");
+   return;
+   }
debugfs_file = debugfs_create_file("fadump_region", 0444,
powerpc_debugfs_root, NULL,
&fadump_region_fops);
@@ -1452,11 +1450,47 @@ static void fadump_init_files(void)
printk(KERN_ERR "fadump: unable to create debugfs file"
" fadump_region\n");
 
+   rc = sysfs_create_file(fadump_kobj, &enable_attr.attr);
+   if (rc)
+   pr_err(