If this is the first LED associated with the device, create the /sys/block/<disk>/blkdev_leds directory. Otherwise, increment its reference count.
Create symlinks in /sys/class/leds/<led>/block_devices and /sys/block/<disk>/blkdev_leds If this the first device associated with any LED, schedule delayed work to periodically check associated devices and blink LEDs Signed-off-by: Ian Pilcher <[email protected]> --- drivers/leds/trigger/ledtrig-blkdev.c | 168 ++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) diff --git a/drivers/leds/trigger/ledtrig-blkdev.c b/drivers/leds/trigger/ledtrig-blkdev.c index 2072cc904616..a1646752b9a0 100644 --- a/drivers/leds/trigger/ledtrig-blkdev.c +++ b/drivers/leds/trigger/ledtrig-blkdev.c @@ -312,3 +312,171 @@ void ledtrig_blkdev_disk_cleanup(struct gendisk *const gd) mutex_unlock(&ledtrig_blkdev_mutex); } EXPORT_SYMBOL_GPL(ledtrig_blkdev_disk_cleanup); + + +/* + * + * Associate a block device with an LED + * + */ + +/* Gets or allocs & initializes the blkdev disk for a gendisk */ +static int blkdev_get_disk(struct gendisk *const gd) +{ + struct ledtrig_blkdev_disk *disk; + struct kobject *dir; + + if (gd->ledtrig != NULL) { + kobject_get(gd->ledtrig->dir); + return 0; + } + + disk = kmalloc(sizeof(*disk), GFP_KERNEL); + if (disk == NULL) + return -ENOMEM; + + dir = blkdev_mkdir("blkdev_leds", &disk_to_dev(gd)->kobj); + if (IS_ERR(dir)) { + kfree(disk); + return PTR_ERR(dir); + } + + INIT_HLIST_HEAD(&disk->leds); + disk->gd = gd; + disk->dir = dir; + disk->read_ios = 0; + disk->write_ios = 0; + + gd->ledtrig = disk; + + return 0; +} + +static void blkdev_put_disk(struct ledtrig_blkdev_disk *const disk) +{ + kobject_put(disk->dir); + + if (hlist_empty(&disk->leds)) { + disk->gd->ledtrig = NULL; + kfree(disk); + } +} + +static int blkdev_disk_add_locked(struct ledtrig_blkdev_led *const led, + struct gendisk *const gd) +{ + struct ledtrig_blkdev_link *link; + struct ledtrig_blkdev_disk *disk; + unsigned long delay; + int ret; + + link = kmalloc(sizeof(*link), GFP_KERNEL); + if (link == NULL) { + ret = -ENOMEM; + goto error_return; + } + + ret = blkdev_get_disk(gd); + if (ret != 0) + goto error_free_link; + + disk = gd->ledtrig; + + ret = sysfs_create_link(disk->dir, &led->led_dev->dev->kobj, + led->led_dev->name); + if (ret != 0) + goto error_put_disk; + + ret = sysfs_create_link(led->dir, &disk_to_dev(gd)->kobj, + gd->disk_name); + if (ret != 0) + goto error_remove_link; + + link->disk = disk; + link->led = led; + hlist_add_head(&link->led_disks_node, &led->disks); + hlist_add_head(&link->disk_leds_node, &disk->leds); + + if (ledtrig_blkdev_count == 0) { + delay = READ_ONCE(ledtrig_blkdev_interval); + WARN_ON(!schedule_delayed_work(&ledtrig_blkdev_work, delay)); + } + + ++ledtrig_blkdev_count; + + return 0; + +error_remove_link: + sysfs_remove_link(disk->dir, led->led_dev->name); +error_put_disk: + blkdev_put_disk(disk); +error_free_link: + kfree(link); +error_return: + return ret; +} + +static bool blkdev_already_linked(const struct ledtrig_blkdev_led *const led, + const struct gendisk *const gd) +{ + const struct ledtrig_blkdev_link *link; + + if (gd->ledtrig == NULL) + return false; + + hlist_for_each_entry(link, &gd->ledtrig->leds, disk_leds_node) { + + if (link->led == led) { + pr_info("blkdev LED: %s already associated with %s\n", + gd->disk_name, led->led_dev->name); + return true; + } + } + + return false; +} + +static int blkdev_disk_add(struct ledtrig_blkdev_led *const led, + const char *const disk_name, const size_t name_len) +{ + static char name[DISK_NAME_LEN]; /* only used w/ mutex locked */ + struct gendisk *gd; + int ret; + + if (name_len >= DISK_NAME_LEN) { + pr_info("blkdev LED: invalid device name %.*s\n", + (int)name_len, disk_name); + ret = -EINVAL; + goto exit_return; + } + + ret = mutex_lock_interruptible(&ledtrig_blkdev_mutex); + if (ret != 0) + goto exit_return; + + memcpy(name, disk_name, name_len); + name[name_len] = 0; + gd = get_disk_by_name(name); /* increments disk's refcount */ + + if (gd == NULL) { + pr_info("blkdev LED: no such block device %.*s\n", + (int)name_len, disk_name); + ret = -ENODEV; + goto exit_unlock; + } + + if (blkdev_already_linked(led, gd)) { + ret = -EEXIST; + goto exit_put_dev; + } + + ret = blkdev_disk_add_locked(led, gd); + +exit_put_dev: + if (ret != 0) + put_device(disk_to_dev(gd)); +exit_unlock: + mutex_unlock(&ledtrig_blkdev_mutex); +exit_return: + return ret; +} -- 2.31.1 _______________________________________________ Kernelnewbies mailing list [email protected] https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
