From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kay Sievers Date: Sat, 01 Oct 2005 12:49:43 +0000 Subject: [RFC] coldplug - emit hotplug events from sysfs Message-Id: <20051001124943.GA26076@vrfy.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org Here is another approach to address the coldplug problem. After playing around with "udevsythesize" it felt stupid to try to compose all the events from sysfs values which will never be exactly the same as the kernel event. This patch adds a "uevent" file to all class/block/bus-devices. Writing to this file, will just emit the hotplug event from the kernel again. udevstart and all the coldplug logic can be 3 lines of shell-script now. Boots fine and is _very_ fast on my box. What do you think? Thanks, Kay ------------ From: Kay Sievers Subject: add sysfs attr to re-emit device hotplug event A "coldplug + udevstart" can be simple like this: for i in /sys/block/*/*/uevent; do echo 1 > $i; done for i in /sys/class/*/*/uevent; do echo 1 > $i; done for i in /sys/bus/*/devices/*/uevent; do echo 1 > $i; done Signed-off-by: Kay Sievers --- diff --git a/drivers/base/class.c b/drivers/base/class.c --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -442,6 +442,13 @@ static ssize_t show_dev(struct class_dev return print_dev_t(buf, class_dev->devt); } +static ssize_t store_uevent(struct class_device *class_dev, + const char *buf, size_t count) +{ + kobject_hotplug(&class_dev->kobj, KOBJ_ADD); + return count; +} + void class_device_initialize(struct class_device *class_dev) { kobj_set_kset_s(class_dev, class_obj_subsys); @@ -497,6 +504,12 @@ int class_device_add(struct class_device goto register_done; /* add the needed attributes to this device */ + class_dev->uevent_attr.attr.name = "uevent"; + class_dev->uevent_attr.attr.mode = S_IWUSR; + class_dev->uevent_attr.attr.owner = parent->owner; + class_dev->uevent_attr.store = store_uevent; + class_device_create_file(class_dev, &class_dev->uevent_attr); + if (MAJOR(class_dev->devt)) { struct class_device_attribute *attr; attr = kzalloc(sizeof(*attr), GFP_KERNEL); @@ -505,12 +518,10 @@ int class_device_add(struct class_device kobject_del(&class_dev->kobj); goto register_done; } - attr->attr.name = "dev"; attr->attr.mode = S_IRUGO; attr->attr.owner = parent->owner; attr->show = show_dev; - attr->store = NULL; class_device_create_file(class_dev, attr); class_dev->devt_attr = attr; } @@ -620,6 +631,7 @@ void class_device_del(struct class_devic sysfs_remove_link(&class_dev->kobj, "device"); sysfs_remove_link(&class_dev->dev->kobj, class_name); } + class_device_remove_file(class_dev, &class_dev->uevent_attr); if (class_dev->devt_attr) class_device_remove_file(class_dev, class_dev->devt_attr); class_device_remove_attrs(class_dev); diff --git a/drivers/base/core.c b/drivers/base/core.c --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -154,6 +154,13 @@ static struct kset_hotplug_ops device_ho .hotplug = dev_hotplug, }; +static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + kobject_hotplug(&dev->kobj, KOBJ_ADD); + return count; +} + /** * device_subsys - structure to be registered with kobject core. */ @@ -258,6 +265,14 @@ int device_add(struct device *dev) if ((error = kobject_add(&dev->kobj))) goto Error; + + dev->uevent_attr.attr.name = "uevent"; + dev->uevent_attr.attr.mode = S_IWUSR; + if (dev->driver) + dev->uevent_attr.attr.owner = dev->driver->owner; + dev->uevent_attr.store = store_uevent; + device_create_file(dev, &dev->uevent_attr); + kobject_hotplug(&dev->kobj, KOBJ_ADD); if ((error = device_pm_add(dev))) goto PMError; @@ -349,6 +364,7 @@ void device_del(struct device * dev) if (parent) klist_del(&dev->knode_parent); + device_remove_file(dev, &dev->uevent_attr); /* Notify the platform of the removal, in case they * need to do anything... diff --git a/drivers/block/genhd.c b/drivers/block/genhd.c --- a/drivers/block/genhd.c +++ b/drivers/block/genhd.c @@ -337,10 +337,30 @@ static ssize_t disk_attr_show(struct kob return ret; } +static ssize_t disk_attr_store(struct kobject * kobj, struct attribute * attr, + const char *page, size_t count) +{ + struct gendisk *disk = to_disk(kobj); + struct disk_attribute *disk_attr + container_of(attr,struct disk_attribute,attr); + ssize_t ret = 0; + + if (disk_attr->store) + ret = disk_attr->store(disk, page, count); + return ret; +} + static struct sysfs_ops disk_sysfs_ops = { .show = &disk_attr_show, + .store = &disk_attr_store, }; +static ssize_t disk_uevent_store(struct gendisk * disk, + const char *buf, size_t count) +{ + kobject_hotplug(&disk->kobj, KOBJ_ADD); + return count; +} static ssize_t disk_dev_read(struct gendisk * disk, char *page) { dev_t base = MKDEV(disk->major, disk->first_minor); @@ -382,6 +402,10 @@ static ssize_t disk_stats_read(struct ge jiffies_to_msecs(disk_stat_read(disk, io_ticks)), jiffies_to_msecs(disk_stat_read(disk, time_in_queue))); } +static struct disk_attribute disk_attr_uevent = { + .attr = {.name = "uevent", .mode = S_IWUSR }, + .store = disk_uevent_store +}; static struct disk_attribute disk_attr_dev = { .attr = {.name = "dev", .mode = S_IRUGO }, .show = disk_dev_read @@ -404,6 +428,7 @@ static struct disk_attribute disk_attr_s }; static struct attribute * default_attrs[] = { + &disk_attr_uevent.attr, &disk_attr_dev.attr, &disk_attr_range.attr, &disk_attr_removable.attr, diff --git a/fs/partitions/check.c b/fs/partitions/check.c --- a/fs/partitions/check.c +++ b/fs/partitions/check.c @@ -192,6 +192,7 @@ check_partition(struct gendisk *hd, stru struct part_attribute { struct attribute attr; ssize_t (*show)(struct hd_struct *,char *); + ssize_t (*store)(struct hd_struct *,const char *, size_t); }; static ssize_t @@ -201,14 +202,33 @@ part_attr_show(struct kobject * kobj, st struct part_attribute * part_attr = container_of(attr,struct part_attribute,attr); ssize_t ret = 0; if (part_attr->show) - ret = part_attr->show(p,page); + ret = part_attr->show(p, page); + return ret; +} +static ssize_t +part_attr_store(struct kobject * kobj, struct attribute * attr, + const char *page, size_t count) +{ + struct hd_struct * p = container_of(kobj,struct hd_struct,kobj); + struct part_attribute * part_attr = container_of(attr,struct part_attribute,attr); + ssize_t ret = 0; + + if (part_attr->store) + ret = part_attr->store(p, page, count); return ret; } static struct sysfs_ops part_sysfs_ops = { .show = part_attr_show, + .store = part_attr_store, }; +static ssize_t part_uevent_store(struct hd_struct * p, + const char *page, size_t count) +{ + kobject_hotplug(&p->kobj, KOBJ_ADD); + return count; +} static ssize_t part_dev_read(struct hd_struct * p, char *page) { struct gendisk *disk = container_of(p->kobj.parent,struct gendisk,kobj); @@ -229,6 +249,10 @@ static ssize_t part_stat_read(struct hd_ p->reads, (unsigned long long)p->read_sectors, p->writes, (unsigned long long)p->write_sectors); } +static struct part_attribute part_attr_uevent = { + .attr = {.name = "uevent", .mode = S_IWUSR }, + .store = part_uevent_store +}; static struct part_attribute part_attr_dev = { .attr = {.name = "dev", .mode = S_IRUGO }, .show = part_dev_read @@ -247,6 +271,7 @@ static struct part_attribute part_attr_s }; static struct attribute * default_attrs[] = { + &part_attr_uevent.attr, &part_attr_dev.attr, &part_attr_start.attr, &part_attr_size.attr, diff --git a/include/linux/device.h b/include/linux/device.h --- a/include/linux/device.h +++ b/include/linux/device.h @@ -190,6 +190,18 @@ struct class_attribute class_attr_##_nam extern int class_create_file(struct class *, const struct class_attribute *); extern void class_remove_file(struct class *, const struct class_attribute *); +struct class_device_attribute { + struct attribute attr; + ssize_t (*show)(struct class_device *, char * buf); + ssize_t (*store)(struct class_device *, const char * buf, size_t count); +}; + +#define CLASS_DEVICE_ATTR(_name,_mode,_show,_store) \ +struct class_device_attribute class_device_attr_##_name = \ + __ATTR(_name,_mode,_show,_store) + +extern int class_device_create_file(struct class_device *, + const struct class_device_attribute *); struct class_device { struct list_head node; @@ -198,6 +210,7 @@ struct class_device { struct class * class; /* required */ dev_t devt; /* dev_t, creates the sysfs "dev" */ struct class_device_attribute *devt_attr; + struct class_device_attribute uevent_attr; struct device * dev; /* not necessary, but nice to have */ void * class_data; /* class-specific data */ @@ -228,18 +241,6 @@ extern int class_device_rename(struct cl extern struct class_device * class_device_get(struct class_device *); extern void class_device_put(struct class_device *); -struct class_device_attribute { - struct attribute attr; - ssize_t (*show)(struct class_device *, char * buf); - ssize_t (*store)(struct class_device *, const char * buf, size_t count); -}; - -#define CLASS_DEVICE_ATTR(_name,_mode,_show,_store) \ -struct class_device_attribute class_device_attr_##_name = \ - __ATTR(_name,_mode,_show,_store) - -extern int class_device_create_file(struct class_device *, - const struct class_device_attribute *); extern void class_device_remove_file(struct class_device *, const struct class_device_attribute *); extern int class_device_create_bin_file(struct class_device *, @@ -266,6 +267,20 @@ extern struct class_device *class_device extern void class_device_destroy(struct class *cls, dev_t devt); +/* interface for exporting device attributes */ +struct device_attribute { + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); +}; + +#define DEVICE_ATTR(_name,_mode,_show,_store) \ +struct device_attribute dev_attr_##_name = __ATTR(_name,_mode,_show,_store) + +extern int device_create_file(struct device *device, struct device_attribute * entry); +extern void device_remove_file(struct device * dev, struct device_attribute * attr); struct device { struct klist klist_children; struct klist_node knode_parent; /* node in sibling list */ @@ -275,6 +290,7 @@ struct device { struct kobject kobj; char bus_id[BUS_ID_SIZE]; /* position on parent bus */ + struct device_attribute uevent_attr; struct semaphore sem; /* semaphore to synchronize calls to * its driver. @@ -343,23 +359,6 @@ extern int device_attach(struct device extern void driver_attach(struct device_driver * drv); -/* driverfs interface for exporting device attributes */ - -struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device *dev, struct device_attribute *attr, - char *buf); - ssize_t (*store)(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count); -}; - -#define DEVICE_ATTR(_name,_mode,_show,_store) \ -struct device_attribute dev_attr_##_name = __ATTR(_name,_mode,_show,_store) - - -extern int device_create_file(struct device *device, struct device_attribute * entry); -extern void device_remove_file(struct device * dev, struct device_attribute * attr); - /* * Platform "fixup" functions - allow the platform to have their say * about devices and actions that the general device layer doesn't diff --git a/include/linux/genhd.h b/include/linux/genhd.h --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -132,6 +132,7 @@ struct gendisk { struct disk_attribute { struct attribute attr; ssize_t (*show)(struct gendisk *, char *); + ssize_t (*store)(struct gendisk *, const char *, size_t); 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