/* * Sample kobject implementation * * Copyright (C) 2004-2007 Greg Kroah-Hartman * Copyright (C) 2007 Novell Inc. * * Released under the GPL version 2 only. * */ #include #include #include #include #include /* * This module shows how to create a simple subdirectory in sysfs called * /sys/kernel/kobject-example In that directory, 3 files are created: * "foo", "baz", and "bar". If an integer is written to these files, it can be * later read out of it. */ static int foo; static int baz; static int bar; /* * The "foo" file where a static variable is read from and written to. */ static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sprintf(buf, "%d\n", foo); } static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int ret; ret = kstrtoint(buf, 10, &foo); if (ret < 0) return ret; return count; } /* Sysfs attributes cannot be world-writable. */ static struct kobj_attribute foo_attribute = __ATTR(foo, 0664, foo_show, foo_store); /* * More complex function where we determine which variable is being accessed by * looking at the attribute for the "baz" and "bar" files. */ static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { int var; if (strcmp(attr->attr.name, "baz") == 0) var = baz; else var = bar; return sprintf(buf, "%d\n", var); } static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int var, ret; ret = kstrtoint(buf, 10, &var); if (ret < 0) return ret; if (strcmp(attr->attr.name, "baz") == 0) baz = var; else bar = var; return count; } static struct kobj_attribute baz_attribute = __ATTR(baz, 0664, b_show, b_store); static struct kobj_attribute bar_attribute = __ATTR(bar, 0664, b_show, b_store); /* * Create a group of attributes so that we can create and destroy them all * at once. */ static struct attribute *attrs[] = { &foo_attribute.attr, &baz_attribute.attr, &bar_attribute.attr, NULL, /* need to NULL terminate the list of attributes */ }; /* * An unnamed attribute group will put all of the attributes directly in * the kobject directory. If we specify a name, a subdirectory will be * created for the attributes with the directory being the name of the * attribute group. */ static struct attribute_group attr_group = { .attrs = attrs, }; static struct kobject *example_kobj; static int __init example_init(void) { int retval; /* * Create a simple kobject with the name of "kobject_example", * located under /sys/kernel/ * * As this is a simple directory, no uevent will be sent to * userspace. That is why this function should not be used for * any type of dynamic kobjects, where the name and number are * not known ahead of time. */ example_kobj = kobject_create_and_add("kobject_example", kernel_kobj); if (!example_kobj) return -ENOMEM; /* Create the files associated with this kobject */ retval = sysfs_create_group(example_kobj, &attr_group); if (retval) kobject_put(example_kobj); return retval; } static void __exit example_exit(void) { kobject_put(example_kobj); } module_init(example_init); module_exit(example_exit); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Greg Kroah-Hartman "); AuthorFilesLines l'>
authorDaniel Borkmann <daniel@iogearbox.net>2017-02-02 17:09:54 +0100
committerDavid S. Miller <davem@davemloft.net>2017-02-03 15:50:18 -0500
commit3898fac1f488c76e0eef5b5267b4ba8112a82ac4 (patch)
treefc6ee165a3338409580a8784111f53c10b22c6d5
parentf38c5ad79f1eb5569843ea24ac7f4cabccc3c657 (diff)
trace: rename trace_print_hex_seq arg and add kdoc
Steven suggested to improve trace_print_hex_seq() a bit after commit 2acae0d5b0f7 ("trace: add variant without spacing in trace_print_hex_seq") in two ways: i) by adding a kdoc comment for the helper function itself and ii) by renaming 'spacing' argument into 'concatenate' to better denote that we don't add spaces between each hex bytes. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat
-rw-r--r--include/linux/trace_events.h2
-rw-r--r--include/trace/trace_events.h4
-rw-r--r--kernel/trace/trace_output.c15
3 files changed, 16 insertions, 5 deletions
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h