The events_queue_size sysfs attribute provides a way for users to dynamically configure the Counter events queue size for the Counter character device interface. The size is in number of struct counter_event data structures. The number of elements will be rounded-up to a power of 2 due to a requirement of the kfifo_alloc function called during reallocation of the queue.
Cc: Oleksij Rempel <[email protected]> Signed-off-by: William Breathitt Gray <[email protected]> --- Documentation/ABI/testing/sysfs-bus-counter | 8 +++++++ drivers/counter/counter-chrdev.c | 23 +++++++++++++++++++ drivers/counter/counter-chrdev.h | 2 ++ drivers/counter/counter-sysfs.c | 25 +++++++++++++++++++++ 4 files changed, 58 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter index 847e96f19d19..f6cb2a8b08a7 100644 --- a/Documentation/ABI/testing/sysfs-bus-counter +++ b/Documentation/ABI/testing/sysfs-bus-counter @@ -212,6 +212,14 @@ Description: both edges: Any state transition. +What: /sys/bus/counter/devices/counterX/events_queue_size +KernelVersion: 5.13 +Contact: [email protected] +Description: + Size of the Counter events queue in number of struct + counter_event data structures. The number of elements will be + rounded-up to a power of 2. + What: /sys/bus/counter/devices/counterX/name KernelVersion: 5.2 Contact: [email protected] diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c index 16f02df7f73d..53eea894e13f 100644 --- a/drivers/counter/counter-chrdev.c +++ b/drivers/counter/counter-chrdev.c @@ -375,6 +375,29 @@ void counter_chrdev_remove(struct counter_device *const counter) cdev_del(&counter->chrdev); } +int counter_chrdev_realloc_queue(struct counter_device *const counter, + size_t queue_size) +{ + int err; + DECLARE_KFIFO_PTR(events, struct counter_event); + unsigned long flags; + + /* Allocate new events queue */ + err = kfifo_alloc(&events, queue_size, GFP_ATOMIC); + if (err) + return err; + + raw_spin_lock_irqsave(&counter->events_list_lock, flags); + + /* Swap in new events queue */ + kfifo_free(&counter->events); + counter->events.kfifo = events.kfifo; + + raw_spin_unlock_irqrestore(&counter->events_list_lock, flags); + + return 0; +} + static int counter_get_data(struct counter_device *const counter, const struct counter_comp_node *const comp_node, u64 *const value) diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h index cf5a318fe540..ff7fb0191852 100644 --- a/drivers/counter/counter-chrdev.h +++ b/drivers/counter/counter-chrdev.h @@ -12,5 +12,7 @@ int counter_chrdev_add(struct counter_device *const counter, const dev_t counter_devt); void counter_chrdev_remove(struct counter_device *const counter); +int counter_chrdev_realloc_queue(struct counter_device *const counter, + size_t queue_size); #endif /* _COUNTER_CHRDEV_H_ */ diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c index 0cb3dba950bc..9abc821a3871 100644 --- a/drivers/counter/counter-sysfs.c +++ b/drivers/counter/counter-sysfs.c @@ -13,6 +13,7 @@ #include <linux/sysfs.h> #include <linux/types.h> +#include "counter-chrdev.h" #include "counter-sysfs.h" /** @@ -737,12 +738,30 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val) return 0; } +static int counter_events_queue_size_read(struct counter_device *counter, + u64 *val) +{ + *val = counter->events.kfifo.mask + 1; + return 0; +} + +static int counter_events_queue_size_write(struct counter_device *counter, + u64 val) +{ + return counter_chrdev_realloc_queue(counter, val); +} + static struct counter_comp counter_num_signals_comp = COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL); static struct counter_comp counter_num_counts_comp = COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL); +static struct counter_comp counter_events_queue_size_comp = + COUNTER_COMP_DEVICE_U64("events_queue_size", + counter_events_queue_size_read, + counter_events_queue_size_write); + static int counter_sysfs_attr_add(struct counter_device *const counter, struct counter_attribute_group *group) { @@ -781,6 +800,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter, if (err < 0) return err; + /* Create num_counts attribute */ + err = counter_attr_create(dev, group, &counter_events_queue_size_comp, + scope, NULL); + if (err < 0) + return err; + /* Create an attribute for each extension */ for (i = 0; i < counter->num_ext; i++) { ext = counter->ext + i; -- 2.30.0
