Re: export of SEQNUM to userspace

[Greg KH <greg@kroah.com>]

On Fri, Sep 03, 2004 at 02:21:06AM +0200, Kay Sievers wrote:
> Something like this?
> 
> o /sys/kernel/hotplug_seqnum exports the current number
> o lib/kobject.c's  sequence_num is renamed to hotplug_seqnum and
>   exported by include/linux/kobject.h
> o the source file ksysfs.c in kernel/ creates on init the
>   sybsystem "/sys/kernel/" in sysfs

Nice, I like it.  How about this, smaller version instead.  I just
changed your code to use the __ATTR* macros and named a few variables a
bit better, no "g" variables for me :)

Is this ok with you?

thanks,

greg k-h

------


diff -Nru a/include/linux/kobject.h b/include/linux/kobject.h
--- a/include/linux/kobject.h	2004-09-03 11:00:55 +02:00
+++ b/include/linux/kobject.h	2004-09-03 11:00:55 +02:00
@@ -24,6 +24,9 @@
 
 #define KOBJ_NAME_LEN	20
 
+/* counter to tag the hotplug event, read only except for the kobject core */
+extern unsigned long hotplug_seqnum;
+
 struct kobject {
 	char			* k_name;
 	char			name[KOBJ_NAME_LEN];
diff -Nru a/kernel/Makefile b/kernel/Makefile
--- a/kernel/Makefile	2004-09-03 11:00:55 +02:00
+++ b/kernel/Makefile	2004-09-03 11:00:55 +02:00
@@ -7,7 +7,7 @@
 	    sysctl.o capability.o ptrace.o timer.o user.o \
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o intermodule.o extable.o params.o posix-timers.o \
-	    kthread.o
+	    kthread.o ksysfs.o
 
 obj-$(CONFIG_FUTEX) += futex.o
 obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
diff -Nru a/kernel/ksysfs.c b/kernel/ksysfs.c
--- /dev/null	Wed Dec 31 16:00:00 196900
+++ b/kernel/ksysfs.c	2004-09-03 11:00:55 +02:00
@@ -0,0 +1,52 @@
+/*
+ * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
+ * 		     are not related to any other subsystem
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * 
+ * This file is release under the GPLv2
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/kobject.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#define KERNEL_ATTR_RO(_name) \
+static struct subsys_attribute _name##_attr = __ATTR_RO(_name)
+
+#define KERNEL_ATTR_RW(_name) \
+static struct subsys_attribute _name##_attr = \
+	__ATTR(_name, 0644, _name##_show, _name##_store)
+
+static ssize_t hotplug_seqnum_show(struct subsystem *subsys, char *page)
+{
+	return sprintf(page, "%lu\n", hotplug_seqnum);
+}
+KERNEL_ATTR_RO(hotplug_seqnum);
+
+
+static decl_subsys(kernel, NULL, NULL);
+
+static struct attribute * kernel_attrs[] = {
+	&hotplug_seqnum_attr.attr,
+	NULL
+};
+
+static struct attribute_group kernel_attr_group = {
+	.attrs = kernel_attrs,
+};
+
+static int __init ksysfs_init(void)
+{
+	int error = subsystem_register(&kernel_subsys);
+	if (!error)
+		error = sysfs_create_group(&kernel_subsys.kset.kobj, &kernel_attr_group);
+
+	return error;
+}
+
+core_initcall(ksysfs_init);
diff -Nru a/lib/kobject.c b/lib/kobject.c
--- a/lib/kobject.c	2004-09-03 11:00:55 +02:00
+++ b/lib/kobject.c	2004-09-03 11:00:55 +02:00
@@ -120,7 +120,7 @@
 
 #define BUFFER_SIZE	1024	/* should be enough memory for the env */
 #define NUM_ENVP	32	/* number of env pointers */
-static unsigned long sequence_num;
+unsigned long hotplug_seqnum;
 static spinlock_t sequence_lock = SPIN_LOCK_UNLOCKED;
 
 static void kset_hotplug(const char *action, struct kset *kset,
@@ -176,7 +176,7 @@
 	scratch += sprintf(scratch, "ACTION=%s", action) + 1;
 
 	spin_lock(&sequence_lock);
-	seq = sequence_num++;
+	seq = hotplug_seqnum++;
 	spin_unlock(&sequence_lock);
 
 	envp [i++] = scratch;


-------------------------------------------------------
This SF.Net email is sponsored by BEA Weblogic Workshop
FREE Java Enterprise J2EE developer tools!
Get your free copy of BEA WebLogic Workshop 8.1 today.
http://ads.osdn.com/?ad_idP47&alloc_id\x10808&op=click
_______________________________________________
Linux-hotplug-devel mailing list  http://linux-hotplug.sourceforge.net
Linux-hotplug-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel