ÔÚ 2021/8/9 ÉÏÎç11:32, Ian Pilcher дµÀ: > Add show & store functions in blk-ledtrig.c (attributes defined in genhd.c) > > Show function shows all available LEDs (LEDs associated with blkdev trigger); > currently associated LED is shown in square brackets ([]) > > Store function accepts either all whitespace or "none" to clear LED > > Signed-off-by: Ian Pilcher > --- > block/blk-ledtrig.c | 109 ++++++++++++++++++++++++++++++++++++++++++++ > block/blk-ledtrig.h | 8 ++++ > block/genhd.c | 8 ++++ > 3 files changed, 125 insertions(+) > > diff --git a/block/blk-ledtrig.c b/block/blk-ledtrig.c > index 280fa9edc2dd..1af94dc7ea51 100644 > --- a/block/blk-ledtrig.c > +++ b/block/blk-ledtrig.c > @@ -6,6 +6,7 @@ > * Copyright 2021 Ian Pilcher > */ > > +#include > #include > #include > #include > @@ -139,3 +140,111 @@ static int blk_ledtrig_dev_set(struct gendisk *const disk, > led_set_exit_return: > return ret; > } > + > + > +/* > + * > + * sysfs attribute store function to set or clear device LED > + * > + */ > + > +// Returns a pointer to the first non-whitespace character in s (or a pointer > +// to the terminating null). > +static const char *blk_ledtrig_skip_whitespace(const char *s) > +{ > + while (*s != 0 && isspace(*s)) > + ++s; > + > + return s; > +} > + > +// Returns a pointer to the first whitespace character in s (or a pointer to > +// the terminating null), which is effectively a pointer to the position *after* > +// the last character in the non-whitespace token at the beginning of s. (s is > +// expected to be the result of a previous call to blk_ledtrig_skip_whitespace.) These are not linux kernel style comments. > +static const char *blk_ledtrig_find_whitespace(const char *s) > +{ > + while (*s != 0 && !isspace(*s)) > + ++s; > + > + return s; > +} > + > +static bool blk_ledtrig_name_is_none(const char *const name, const size_t len) > +{ > + static const char none[4] = "none"; // no terminating null > + > + return len == sizeof(none) && memcmp(name, none, sizeof(none)) == 0; > +} > + > +ssize_t blk_ledtrig_dev_led_store(struct device *const dev, > + struct device_attribute *const attr, > + const char *const buf, const size_t count) > +{ > + struct gendisk *const disk = dev_to_disk(dev); > + const char *const led_name = blk_ledtrig_skip_whitespace(buf); > + const char *const endp = blk_ledtrig_find_whitespace(led_name); > + const ptrdiff_t name_len = endp - led_name; // always >= 0 > + int ret; > + > + if (name_len == 0 || blk_ledtrig_name_is_none(led_name, name_len)) { > + blk_ledtrig_dev_clear(disk); > + ret = 0; > + } else { > + ret = blk_ledtrig_dev_set(disk, led_name, name_len); > + } > + > + if (ret < 0) > + return ret; > + > + return count; > +} > + > + > +/* > + * > + * sysfs attribute show function for device LED > + * > + */ > + > +ssize_t blk_ledtrig_dev_led_show(struct device *const dev, > + struct device_attribute *const attr, > + char *const buf) > +{ > + struct gendisk *const disk = dev_to_disk(dev); > + struct blk_ledtrig_led *bd_led, *disk_led; > + int ret, c = 0; > + > + ret = mutex_lock_interruptible(&blk_ledtrig_mutex); > + if (ret != 0) > + goto led_show_exit_return; > + > + disk_led = rcu_dereference_protected(disk->led, > + lockdep_is_held(&blk_ledtrig_mutex)); > + > + if (disk_led == NULL) > + c += sprintf(buf, "[none]"); > + else > + c += sprintf(buf, "none"); > + > + list_for_each_entry(bd_led, &blk_ledtrig_leds, leds_list_node) { > + > + ret = snprintf(buf + c, PAGE_SIZE - c - 1, > + bd_led == disk_led ? " [%s]" : " %s", > + bd_led->led->name); > + if (ret >= PAGE_SIZE - c - 1) { > + ret = -EOVERFLOW; > + goto led_show_exit_unlock; > + } > + > + c += ret; > + } > + > + buf[c] = '\n'; > + ret = c + 1; > + > +led_show_exit_unlock: > + mutex_unlock(&blk_ledtrig_mutex); > +led_show_exit_return: > + return ret; > +} > diff --git a/block/blk-ledtrig.h b/block/blk-ledtrig.h > index 66a1302a4174..771000d43647 100644 > --- a/block/blk-ledtrig.h > +++ b/block/blk-ledtrig.h > @@ -18,6 +18,14 @@ static inline void blk_ledtrig_disk_init(struct gendisk *const disk) > > void blk_ledtrig_dev_clear(struct gendisk *const disk); > > +ssize_t blk_ledtrig_dev_led_store(struct device *const dev, > + struct device_attribute *const attr, > + const char *const buf, const size_t count); > + > +ssize_t blk_ledtrig_dev_led_show(struct device *const dev, > + struct device_attribute *const attr, > + char *const buf); > + > #else // CONFIG_BLK_LED_TRIGGERS > > static inline void blk_ledtrig_disk_init(const struct gendisk *disk) {} > diff --git a/block/genhd.c b/block/genhd.c > index 9fa734aeab0f..d5413a633410 100644 > --- a/block/genhd.c > +++ b/block/genhd.c > @@ -1012,6 +1012,11 @@ static struct device_attribute dev_attr_fail_timeout = > __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store); > #endif > > +#ifdef CONFIG_BLK_LED_TRIGGERS > +static struct device_attribute dev_attr_led = > + __ATTR(led, 0644, blk_ledtrig_dev_led_show, blk_ledtrig_dev_led_store); > +#endif > + > static struct attribute *disk_attrs[] = { > &dev_attr_range.attr, > &dev_attr_ext_range.attr, > @@ -1033,6 +1038,9 @@ static struct attribute *disk_attrs[] = { > #endif > #ifdef CONFIG_FAIL_IO_TIMEOUT > &dev_attr_fail_timeout.attr, > +#endif > +#ifdef CONFIG_BLK_LED_TRIGGERS > + &dev_attr_led.attr, > #endif > NULL > }; >