diff options
| -rw-r--r-- | drivers/comedi/comedi_fops.c | 78 | ||||
| -rw-r--r-- | drivers/comedi/drivers.c | 1 | ||||
| -rw-r--r-- | include/linux/comedi/comedidev.h | 7 |
3 files changed, 78 insertions, 8 deletions
diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c index 40d8b29797ae..8253e4e8232b 100644 --- a/drivers/comedi/comedi_fops.c +++ b/drivers/comedi/comedi_fops.c @@ -38,6 +38,7 @@ * COMEDI_SRF_ERROR: indicates an COMEDI_CB_ERROR event has occurred * since the last command was started * COMEDI_SRF_RUNNING: command is running + * COMEDI_SRF_BUSY: command was started and subdevice still busy * COMEDI_SRF_FREE_SPRIV: free s->private on detach * * COMEDI_SRF_BUSY_MASK: runflags that indicate the subdevice is "busy" @@ -45,9 +46,11 @@ #define COMEDI_SRF_RT BIT(1) #define COMEDI_SRF_ERROR BIT(2) #define COMEDI_SRF_RUNNING BIT(27) +#define COMEDI_SRF_BUSY BIT(28) #define COMEDI_SRF_FREE_SPRIV BIT(31) -#define COMEDI_SRF_BUSY_MASK (COMEDI_SRF_ERROR | COMEDI_SRF_RUNNING) +#define COMEDI_SRF_BUSY_MASK \ + (COMEDI_SRF_ERROR | COMEDI_SRF_RUNNING | COMEDI_SRF_BUSY) /** * struct comedi_file - Per-file private data for COMEDI device @@ -665,6 +668,11 @@ static bool comedi_is_runflags_in_error(unsigned int runflags) return runflags & COMEDI_SRF_ERROR; } +static bool comedi_is_runflags_busy(unsigned int runflags) +{ + return runflags & COMEDI_SRF_BUSY; +} + /** * comedi_is_subdevice_running() - Check if async command running on subdevice * @s: COMEDI subdevice. @@ -687,6 +695,46 @@ static bool __comedi_is_subdevice_running(struct comedi_subdevice *s) return comedi_is_runflags_running(runflags); } +/** + * comedi_get_is_subdevice_running() - Get if async command running on subdevice + * @s: COMEDI subdevice. + * + * If an asynchronous COMEDI command is running on the subdevice, increment + * a reference counter. If the function return value indicates that a + * command is running, then the details of the command will not be destroyed + * before a matching call to comedi_put_is_subdevice_running(). + * + * Return: %true if an asynchronous COMEDI command is active on the + * subdevice, else %false. + */ +bool comedi_get_is_subdevice_running(struct comedi_subdevice *s) +{ + unsigned long flags; + bool running; + + spin_lock_irqsave(&s->spin_lock, flags); + running = __comedi_is_subdevice_running(s); + if (running) + refcount_inc(&s->async->run_active); + spin_unlock_irqrestore(&s->spin_lock, flags); + return running; +} +EXPORT_SYMBOL_GPL(comedi_get_is_subdevice_running); + +/** + * comedi_put_is_subdevice_running() - Put if async command running on subdevice + * @s: COMEDI subdevice. + * + * Decrements the reference counter that was incremented when + * comedi_get_is_subdevice_running() returned %true. + */ +void comedi_put_is_subdevice_running(struct comedi_subdevice *s) +{ + if (refcount_dec_and_test(&s->async->run_active)) + complete_all(&s->async->run_complete); +} +EXPORT_SYMBOL_GPL(comedi_put_is_subdevice_running); + bool comedi_can_auto_free_spriv(struct comedi_subdevice *s) { unsigned int runflags = __comedi_get_subdevice_runflags(s); @@ -736,20 +784,28 @@ static void do_become_nonbusy(struct comedi_device *dev, struct comedi_subdevice *s) { struct comedi_async *async = s->async; + unsigned int runflags; + unsigned long flags; lockdep_assert_held(&dev->mutex); - comedi_update_subdevice_runflags(s, COMEDI_SRF_RUNNING, 0); - if (async) { + spin_lock_irqsave(&s->spin_lock, flags); + runflags = __comedi_get_subdevice_runflags(s); + __comedi_clear_subdevice_runflags(s, COMEDI_SRF_RUNNING | + COMEDI_SRF_BUSY); + spin_unlock_irqrestore(&s->spin_lock, flags); + if (comedi_is_runflags_busy(runflags)) { + /* + * "Run active" counter was set to 1 when setting up the + * command. Decrement it and wait for it to become 0. + */ + comedi_put_is_subdevice_running(s); + wait_for_completion(&async->run_complete); comedi_buf_reset(s); async->inttrig = NULL; kfree(async->cmd.chanlist); async->cmd.chanlist = NULL; s->busy = NULL; wake_up_interruptible_all(&async->wait_head); - } else { - dev_err(dev->class_dev, - "BUG: (?) %s called with async=NULL\n", __func__); - s->busy = NULL; } } @@ -1860,8 +1916,14 @@ static int do_cmd_ioctl(struct comedi_device *dev, if (async->cmd.flags & CMDF_WAKE_EOS) async->cb_mask |= COMEDI_CB_EOS; + /* + * Set the "run active" counter with an initial count of 1 that will + * complete the "safe to reset" event when it is decremented to 0. + */ + refcount_set(&s->async->run_active, 1); + reinit_completion(&s->async->run_complete); comedi_update_subdevice_runflags(s, COMEDI_SRF_BUSY_MASK, - COMEDI_SRF_RUNNING); + COMEDI_SRF_RUNNING | COMEDI_SRF_BUSY); /* * Set s->busy _after_ setting COMEDI_SRF_RUNNING flag to avoid diff --git a/drivers/comedi/drivers.c b/drivers/comedi/drivers.c index c9ebaadc5e82..fd6e6cbe47ad 100644 --- a/drivers/comedi/drivers.c +++ b/drivers/comedi/drivers.c @@ -677,6 +677,7 @@ static int __comedi_device_postconfig_async(struct comedi_device *dev, return -ENOMEM; init_waitqueue_head(&async->wait_head); + init_completion(&async->run_complete); s->async = async; async->max_bufsize = comedi_default_buf_maxsize_kb * 1024; diff --git a/include/linux/comedi/comedidev.h b/include/linux/comedi/comedidev.h index 4cb0400ad616..35fdc41845ce 100644 --- a/include/linux/comedi/comedidev.h +++ b/include/linux/comedi/comedidev.h @@ -15,6 +15,7 @@ #include <linux/spinlock_types.h> #include <linux/rwsem.h> #include <linux/kref.h> +#include <linux/completion.h> #include <linux/comedi.h> #define COMEDI_VERSION(a, b, c) (((a) << 16) + ((b) << 8) + (c)) @@ -272,6 +273,8 @@ struct comedi_buf_map { * @events: Bit-vector of events that have occurred. * @cmd: Details of comedi command in progress. * @wait_head: Task wait queue for file reader or writer. + * @run_complete: "run complete" completion event. + * @run_active: "run active" reference counter. * @cb_mask: Bit-vector of events that should wake waiting tasks. * @inttrig: Software trigger function for command, or NULL. * @@ -357,6 +360,8 @@ struct comedi_async { unsigned int events; struct comedi_cmd cmd; wait_queue_head_t wait_head; + struct completion run_complete; + refcount_t run_active; unsigned int cb_mask; int (*inttrig)(struct comedi_device *dev, struct comedi_subdevice *s, unsigned int x); @@ -584,6 +589,8 @@ struct comedi_device *comedi_dev_get_from_minor(unsigned int minor); int comedi_dev_put(struct comedi_device *dev); bool comedi_is_subdevice_running(struct comedi_subdevice *s); +bool comedi_get_is_subdevice_running(struct comedi_subdevice *s); +void comedi_put_is_subdevice_running(struct comedi_subdevice *s); void *comedi_alloc_spriv(struct comedi_subdevice *s, size_t size); void comedi_set_spriv_auto_free(struct comedi_subdevice *s); |