Merge tag 'char-misc-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc/IIO driver updates from Greg KH:
 "Here is the big set of char/misc/iio driver updates for 6.19-rc1. Lots
  of stuff in here including:

   - lots of IIO driver updates, cleanups, and additions

   - large interconnect driver changes as they get converted over to a
     dynamic system of ids

   - coresight driver updates

   - mwave driver updates

   - binder driver updates and changes

   - comedi driver fixes now that the fuzzers are being set loose on
     them

   - nvmem driver updates

   - new uio driver addition

   - lots of other small char/misc driver updates, full details in the
     shortlog

  All of these have been in linux-next for a while now"

* tag 'char-misc-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (304 commits)
  char: applicom: fix NULL pointer dereference in ac_ioctl
  hangcheck-timer: fix coding style spacing
  hangcheck-timer: Replace %Ld with %lld
  hangcheck-timer: replace printk(KERN_CRIT) with pr_crit
  uio: Add SVA support for PCI devices via uio_pci_generic_sva.c
  dt-bindings: slimbus: fix warning from example
  intel_th: Fix error handling in intel_th_output_open
  misc: rp1: Fix an error handling path in rp1_probe()
  char: xillybus: add WQ_UNBOUND to alloc_workqueue users
  misc: bh1770glc: use pm_runtime_resume_and_get() in power_state_store
  misc: cb710: Fix a NULL vs IS_ERR() check in probe()
  mux: mmio: Add suspend and resume support
  virt: acrn: split acrn_mmio_dev_res out of acrn_mmiodev
  greybus: gb-beagleplay: Fix timeout handling in bootloader functions
  greybus: add WQ_PERCPU to alloc_workqueue users
  char/mwave: drop typedefs
  char/mwave: drop printk wrapper
  char/mwave: remove printk tracing
  char/mwave: remove unneeded fops
  char/mwave: remove MWAVE_FUTZ_WITH_OTHER_DEVICES ifdeffery
  ...

10 files changed, 606 insertions, 207 deletions

diff --git a/drivers/comedi/comedi_buf.c b/drivers/comedi/comedi_buf.c
index c7c262a2d8ca..785977b40a93 100644
--- a/drivers/comedi/comedi_buf.c
+++ b/drivers/comedi/comedi_buf.c
@@ -273,19 +273,8 @@ unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s)
 	return free_end - async->buf_write_count;
 }
 
-/**
- * comedi_buf_write_alloc() - Reserve buffer space for writing
- * @s: COMEDI subdevice.
- * @nbytes: Maximum space to reserve in bytes.
- *
- * Reserve up to @nbytes bytes of space to be written in the COMEDI acquisition
- * data buffer associated with the subdevice.  The amount reserved is limited
- * by the space available.
- *
- * Return: The amount of space reserved in bytes.
- */
-unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s,
-				    unsigned int nbytes)
+unsigned int _comedi_buf_write_alloc(struct comedi_subdevice *s,
+				     unsigned int nbytes)
 {
 	struct comedi_async *async = s->async;
 	unsigned int unalloc = comedi_buf_write_n_unalloc(s);
@@ -303,6 +292,29 @@ unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s,
 
 	return nbytes;
 }
+
+/**
+ * comedi_buf_write_alloc() - Reserve buffer space for writing
+ * @s: COMEDI subdevice.
+ * @nbytes: Maximum space to reserve in bytes.
+ *
+ * Reserve up to @nbytes bytes of space to be written in the COMEDI acquisition
+ * data buffer associated with the subdevice.  The amount reserved is limited
+ * by the space available.
+ *
+ * Return: The amount of space reserved in bytes.
+ */
+unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s,
+				    unsigned int nbytes)
+{
+	if (comedi_get_is_subdevice_running(s)) {
+		nbytes = _comedi_buf_write_alloc(s, nbytes);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nbytes = 0;
+	}
+	return nbytes;
+}
 EXPORT_SYMBOL_GPL(comedi_buf_write_alloc);
 
 /*
@@ -362,6 +374,24 @@ unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s)
 	return async->buf_write_alloc_count - async->buf_write_count;
 }
 
+unsigned int _comedi_buf_write_free(struct comedi_subdevice *s,
+				    unsigned int nbytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int allocated = comedi_buf_write_n_allocated(s);
+
+	if (nbytes > allocated)
+		nbytes = allocated;
+
+	async->buf_write_count += nbytes;
+	async->buf_write_ptr += nbytes;
+	comedi_buf_munge(s, async->buf_write_count - async->munge_count);
+	if (async->buf_write_ptr >= async->prealloc_bufsz)
+		async->buf_write_ptr %= async->prealloc_bufsz;
+
+	return nbytes;
+}
+
 /**
  * comedi_buf_write_free() - Free buffer space after it is written
  * @s: COMEDI subdevice.
@@ -380,21 +410,34 @@ unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s)
 unsigned int comedi_buf_write_free(struct comedi_subdevice *s,
 				   unsigned int nbytes)
 {
+	if (comedi_get_is_subdevice_running(s)) {
+		nbytes = _comedi_buf_write_free(s, nbytes);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nbytes = 0;
+	}
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_write_free);
+
+unsigned int _comedi_buf_read_n_available(struct comedi_subdevice *s)
+{
 	struct comedi_async *async = s->async;
-	unsigned int allocated = comedi_buf_write_n_allocated(s);
+	unsigned int num_bytes;
 
-	if (nbytes > allocated)
-		nbytes = allocated;
+	if (!async)
+		return 0;
 
-	async->buf_write_count += nbytes;
-	async->buf_write_ptr += nbytes;
-	comedi_buf_munge(s, async->buf_write_count - async->munge_count);
-	if (async->buf_write_ptr >= async->prealloc_bufsz)
-		async->buf_write_ptr %= async->prealloc_bufsz;
+	num_bytes = async->munge_count - async->buf_read_count;
 
-	return nbytes;
+	/*
+	 * ensure the async buffer 'counts' are read before we
+	 * attempt to read data from the buffer
+	 */
+	smp_rmb();
+
+	return num_bytes;
 }
-EXPORT_SYMBOL_GPL(comedi_buf_write_free);
 
 /**
  * comedi_buf_read_n_available() - Determine amount of readable buffer space
@@ -409,23 +452,38 @@ EXPORT_SYMBOL_GPL(comedi_buf_write_free);
  */
 unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s)
 {
-	struct comedi_async *async = s->async;
 	unsigned int num_bytes;
 
-	if (!async)
-		return 0;
+	if (comedi_get_is_subdevice_running(s)) {
+		num_bytes = _comedi_buf_read_n_available(s);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		num_bytes = 0;
+	}
+	return num_bytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
 
-	num_bytes = async->munge_count - async->buf_read_count;
+unsigned int _comedi_buf_read_alloc(struct comedi_subdevice *s,
+				    unsigned int nbytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int available;
+
+	available = async->munge_count - async->buf_read_alloc_count;
+	if (nbytes > available)
+		nbytes = available;
+
+	async->buf_read_alloc_count += nbytes;
 
 	/*
 	 * ensure the async buffer 'counts' are read before we
-	 * attempt to read data from the buffer
+	 * attempt to read data from the read-alloc'ed buffer space
 	 */
 	smp_rmb();
 
-	return num_bytes;
+	return nbytes;
 }
-EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
 
 /**
  * comedi_buf_read_alloc() - Reserve buffer space for reading
@@ -445,21 +503,12 @@ EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
 unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s,
 				   unsigned int nbytes)
 {
-	struct comedi_async *async = s->async;
-	unsigned int available;
-
-	available = async->munge_count - async->buf_read_alloc_count;
-	if (nbytes > available)
-		nbytes = available;
-
-	async->buf_read_alloc_count += nbytes;
-
-	/*
-	 * ensure the async buffer 'counts' are read before we
-	 * attempt to read data from the read-alloc'ed buffer space
-	 */
-	smp_rmb();
-
+	if (comedi_get_is_subdevice_running(s)) {
+		nbytes = _comedi_buf_read_alloc(s, nbytes);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nbytes = 0;
+	}
 	return nbytes;
 }
 EXPORT_SYMBOL_GPL(comedi_buf_read_alloc);
@@ -469,21 +518,8 @@ static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async)
 	return async->buf_read_alloc_count - async->buf_read_count;
 }
 
-/**
- * comedi_buf_read_free() - Free buffer space after it has been read
- * @s: COMEDI subdevice.
- * @nbytes: Maximum space to free in bytes.
- *
- * Free up to @nbytes bytes of buffer space previously reserved for reading in
- * the COMEDI acquisition data buffer associated with the subdevice.  The
- * amount of space freed is limited to the amount that was reserved.
- *
- * The freed space becomes available for allocation by the writer.
- *
- * Return: The amount of space freed in bytes.
- */
-unsigned int comedi_buf_read_free(struct comedi_subdevice *s,
-				  unsigned int nbytes)
+unsigned int _comedi_buf_read_free(struct comedi_subdevice *s,
+				   unsigned int nbytes)
 {
 	struct comedi_async *async = s->async;
 	unsigned int allocated;
@@ -503,6 +539,31 @@ unsigned int comedi_buf_read_free(struct comedi_subdevice *s,
 	async->buf_read_ptr %= async->prealloc_bufsz;
 	return nbytes;
 }
+
+/**
+ * comedi_buf_read_free() - Free buffer space after it has been read
+ * @s: COMEDI subdevice.
+ * @nbytes: Maximum space to free in bytes.
+ *
+ * Free up to @nbytes bytes of buffer space previously reserved for reading in
+ * the COMEDI acquisition data buffer associated with the subdevice.  The
+ * amount of space freed is limited to the amount that was reserved.
+ *
+ * The freed space becomes available for allocation by the writer.
+ *
+ * Return: The amount of space freed in bytes.
+ */
+unsigned int comedi_buf_read_free(struct comedi_subdevice *s,
+				  unsigned int nbytes)
+{
+	if (comedi_get_is_subdevice_running(s)) {
+		nbytes = _comedi_buf_read_free(s, nbytes);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nbytes = 0;
+	}
+	return nbytes;
+}
 EXPORT_SYMBOL_GPL(comedi_buf_read_free);
 
 static void comedi_buf_memcpy_to(struct comedi_subdevice *s,
@@ -558,6 +619,38 @@ static void comedi_buf_memcpy_from(struct comedi_subdevice *s,
 	}
 }
 
+static unsigned int _comedi_buf_write_samples(struct comedi_subdevice *s,
+					      const void *data,
+					      unsigned int nsamples)
+{
+	unsigned int max_samples;
+	unsigned int nbytes;
+
+	/*
+	 * Make sure there is enough room in the buffer for all the samples.
+	 * If not, clamp the nsamples to the number that will fit, flag the
+	 * buffer overrun and add the samples that fit.
+	 */
+	max_samples = comedi_bytes_to_samples(s, comedi_buf_write_n_unalloc(s));
+	if (nsamples > max_samples) {
+		dev_warn(s->device->class_dev, "buffer overrun\n");
+		s->async->events |= COMEDI_CB_OVERFLOW;
+		nsamples = max_samples;
+	}
+
+	if (nsamples == 0)
+		return 0;
+
+	nbytes = comedi_samples_to_bytes(s, nsamples);
+	nbytes = _comedi_buf_write_alloc(s, nbytes);
+	comedi_buf_memcpy_to(s, data, nbytes);
+	_comedi_buf_write_free(s, nbytes);
+	_comedi_inc_scan_progress(s, nbytes);
+	s->async->events |= COMEDI_CB_BLOCK;
+
+	return nbytes;
+}
+
 /**
  * comedi_buf_write_samples() - Write sample data to COMEDI buffer
  * @s: COMEDI subdevice.
@@ -578,34 +671,42 @@ static void comedi_buf_memcpy_from(struct comedi_subdevice *s,
 unsigned int comedi_buf_write_samples(struct comedi_subdevice *s,
 				      const void *data, unsigned int nsamples)
 {
+	unsigned int nbytes;
+
+	if (comedi_get_is_subdevice_running(s)) {
+		nbytes = _comedi_buf_write_samples(s, data, nsamples);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nbytes = 0;
+	}
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_write_samples);
+
+static unsigned int _comedi_buf_read_samples(struct comedi_subdevice *s,
+					    void *data, unsigned int nsamples)
+{
 	unsigned int max_samples;
 	unsigned int nbytes;
 
-	/*
-	 * Make sure there is enough room in the buffer for all the samples.
-	 * If not, clamp the nsamples to the number that will fit, flag the
-	 * buffer overrun and add the samples that fit.
-	 */
-	max_samples = comedi_bytes_to_samples(s, comedi_buf_write_n_unalloc(s));
-	if (nsamples > max_samples) {
-		dev_warn(s->device->class_dev, "buffer overrun\n");
-		s->async->events |= COMEDI_CB_OVERFLOW;
+	/* clamp nsamples to the number of full samples available */
+	max_samples = comedi_bytes_to_samples(s,
+					      _comedi_buf_read_n_available(s));
+	if (nsamples > max_samples)
 		nsamples = max_samples;
-	}
 
 	if (nsamples == 0)
 		return 0;
 
-	nbytes = comedi_buf_write_alloc(s,
+	nbytes = _comedi_buf_read_alloc(s,
 					comedi_samples_to_bytes(s, nsamples));
-	comedi_buf_memcpy_to(s, data, nbytes);
-	comedi_buf_write_free(s, nbytes);
-	comedi_inc_scan_progress(s, nbytes);
+	comedi_buf_memcpy_from(s, data, nbytes);
+	_comedi_buf_read_free(s, nbytes);
+	_comedi_inc_scan_progress(s, nbytes);
 	s->async->events |= COMEDI_CB_BLOCK;
 
 	return nbytes;
 }
-EXPORT_SYMBOL_GPL(comedi_buf_write_samples);
 
 /**
  * comedi_buf_read_samples() - Read sample data from COMEDI buffer
@@ -624,25 +725,14 @@ EXPORT_SYMBOL_GPL(comedi_buf_write_samples);
 unsigned int comedi_buf_read_samples(struct comedi_subdevice *s,
 				     void *data, unsigned int nsamples)
 {
-	unsigned int max_samples;
 	unsigned int nbytes;
 
-	/* clamp nsamples to the number of full samples available */
-	max_samples = comedi_bytes_to_samples(s,
-					      comedi_buf_read_n_available(s));
-	if (nsamples > max_samples)
-		nsamples = max_samples;
-
-	if (nsamples == 0)
-		return 0;
-
-	nbytes = comedi_buf_read_alloc(s,
-				       comedi_samples_to_bytes(s, nsamples));
-	comedi_buf_memcpy_from(s, data, nbytes);
-	comedi_buf_read_free(s, nbytes);
-	comedi_inc_scan_progress(s, nbytes);
-	s->async->events |= COMEDI_CB_BLOCK;
-
+	if (comedi_get_is_subdevice_running(s)) {
+		nbytes = _comedi_buf_read_samples(s, data, nsamples);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nbytes = 0;
+	}
 	return nbytes;
 }
 EXPORT_SYMBOL_GPL(comedi_buf_read_samples);
diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
index 7e2f2b1a1c36..657c98cd723e 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;
 	}
 }
 
@@ -1150,15 +1206,15 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
 	if (!(async->cmd.flags & CMDF_WRITE)) {
 		/* command was set up in "read" direction */
 		if (bi.bytes_read) {
-			comedi_buf_read_alloc(s, bi.bytes_read);
-			bi.bytes_read = comedi_buf_read_free(s, bi.bytes_read);
+			_comedi_buf_read_alloc(s, bi.bytes_read);
+			bi.bytes_read = _comedi_buf_read_free(s, bi.bytes_read);
 		}
 		/*
 		 * If nothing left to read, and command has stopped, and
 		 * {"read" position not updated or command stopped normally},
 		 * then become non-busy.
 		 */
-		if (comedi_buf_read_n_available(s) == 0 &&
+		if (_comedi_buf_read_n_available(s) == 0 &&
 		    !comedi_is_runflags_running(runflags) &&
 		    (bi.bytes_read == 0 ||
 		     !comedi_is_runflags_in_error(runflags))) {
@@ -1175,9 +1231,9 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
 			if (comedi_is_runflags_in_error(runflags))
 				retval = -EPIPE;
 		} else if (bi.bytes_written) {
-			comedi_buf_write_alloc(s, bi.bytes_written);
+			_comedi_buf_write_alloc(s, bi.bytes_written);
 			bi.bytes_written =
-			    comedi_buf_write_free(s, bi.bytes_written);
+			    _comedi_buf_write_free(s, bi.bytes_written);
 		}
 		bi.bytes_read = 0;
 	}
@@ -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
@@ -2284,15 +2346,10 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 		rc = check_insnlist_len(dev, insnlist.n_insns);
 		if (rc)
 			break;
-		insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
-		if (!insns) {
-			rc = -ENOMEM;
-			break;
-		}
-		if (copy_from_user(insns, insnlist.insns,
-				   sizeof(*insns) * insnlist.n_insns)) {
-			rc = -EFAULT;
-			kfree(insns);
+		insns = memdup_array_user(insnlist.insns, insnlist.n_insns,
+					  sizeof(*insns));
+		if (IS_ERR(insns)) {
+			rc = PTR_ERR(insns);
 			break;
 		}
 		rc = do_insnlist_ioctl(dev, insns, insnlist.n_insns, file);
@@ -2512,7 +2569,7 @@ static __poll_t comedi_poll(struct file *file, poll_table *wait)
 		poll_wait(file, &s->async->wait_head, wait);
 		if (s->busy != file || !comedi_is_subdevice_running(s) ||
 		    (s->async->cmd.flags & CMDF_WRITE) ||
-		    comedi_buf_read_n_available(s) > 0)
+		    _comedi_buf_read_n_available(s) > 0)
 			mask |= EPOLLIN | EPOLLRDNORM;
 	}
 
@@ -2645,7 +2702,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
 			break;
 
 		/* Allocate all free buffer space. */
-		comedi_buf_write_alloc(s, async->prealloc_bufsz);
+		_comedi_buf_write_alloc(s, async->prealloc_bufsz);
 		m = comedi_buf_write_n_allocated(s);
 		n = min_t(size_t, m, nbytes);
 
@@ -2673,7 +2730,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
 			n -= m;
 			retval = -EFAULT;
 		}
-		comedi_buf_write_free(s, n);
+		_comedi_buf_write_free(s, n);
 
 		count += n;
 		nbytes -= n;
@@ -2759,7 +2816,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 	while (count == 0 && !retval) {
 		set_current_state(TASK_INTERRUPTIBLE);
 
-		m = comedi_buf_read_n_available(s);
+		m = _comedi_buf_read_n_available(s);
 		n = min_t(size_t, m, nbytes);
 
 		if (n == 0) {
@@ -2799,8 +2856,8 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 			retval = -EFAULT;
 		}
 
-		comedi_buf_read_alloc(s, n);
-		comedi_buf_read_free(s, n);
+		_comedi_buf_read_alloc(s, n);
+		_comedi_buf_read_free(s, n);
 
 		count += n;
 		nbytes -= n;
@@ -2834,7 +2891,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 		    s == new_s && new_s->async == async && s->busy == file &&
 		    !(async->cmd.flags & CMDF_WRITE) &&
 		    !comedi_is_subdevice_running(s) &&
-		    comedi_buf_read_n_available(s) == 0)
+		    _comedi_buf_read_n_available(s) == 0)
 			do_become_nonbusy(dev, s);
 		mutex_unlock(&dev->mutex);
 	}
@@ -3023,7 +3080,12 @@ static int compat_chaninfo(struct file *file, unsigned long arg)
 	chaninfo.rangelist = compat_ptr(chaninfo32.rangelist);
 
 	mutex_lock(&dev->mutex);
-	err = do_chaninfo_ioctl(dev, &chaninfo);
+	if (!dev->attached) {
+		dev_dbg(dev->class_dev, "no driver attached\n");
+		err = -ENODEV;
+	} else {
+		err = do_chaninfo_ioctl(dev, &chaninfo);
+	}
 	mutex_unlock(&dev->mutex);
 	return err;
 }
@@ -3044,7 +3106,12 @@ static int compat_rangeinfo(struct file *file, unsigned long arg)
 	rangeinfo.range_ptr = compat_ptr(rangeinfo32.range_ptr);
 
 	mutex_lock(&dev->mutex);
-	err = do_rangeinfo_ioctl(dev, &rangeinfo);
+	if (!dev->attached) {
+		dev_dbg(dev->class_dev, "no driver attached\n");
+		err = -ENODEV;
+	} else {
+		err = do_rangeinfo_ioctl(dev, &rangeinfo);
+	}
 	mutex_unlock(&dev->mutex);
 	return err;
 }
@@ -3120,7 +3187,12 @@ static int compat_cmd(struct file *file, unsigned long arg)
 		return rc;
 
 	mutex_lock(&dev->mutex);
-	rc = do_cmd_ioctl(dev, &cmd, &copy, file);
+	if (!dev->attached) {
+		dev_dbg(dev->class_dev, "no driver attached\n");
+		rc = -ENODEV;
+	} else {
+		rc = do_cmd_ioctl(dev, &cmd, &copy, file);
+	}
 	mutex_unlock(&dev->mutex);
 	if (copy) {
 		/* Special case: copy cmd back to user. */
@@ -3145,7 +3217,12 @@ static int compat_cmdtest(struct file *file, unsigned long arg)
 		return rc;
 
 	mutex_lock(&dev->mutex);
-	rc = do_cmdtest_ioctl(dev, &cmd, &copy, file);
+	if (!dev->attached) {
+		dev_dbg(dev->class_dev, "no driver attached\n");
+		rc = -ENODEV;
+	} else {
+		rc = do_cmdtest_ioctl(dev, &cmd, &copy, file);
+	}
 	mutex_unlock(&dev->mutex);
 	if (copy) {
 		err = put_compat_cmd(compat_ptr(arg), &cmd);
@@ -3205,7 +3282,12 @@ static int compat_insnlist(struct file *file, unsigned long arg)
 	}
 
 	mutex_lock(&dev->mutex);
-	rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file);
+	if (!dev->attached) {
+		dev_dbg(dev->class_dev, "no driver attached\n");
+		rc = -ENODEV;
+	} else {
+		rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file);
+	}
 	mutex_unlock(&dev->mutex);
 	kfree(insns);
 	return rc;
@@ -3224,7 +3306,12 @@ static int compat_insn(struct file *file, unsigned long arg)
 		return rc;
 
 	mutex_lock(&dev->mutex);
-	rc = do_insn_ioctl(dev, &insn, file);
+	if (!dev->attached) {
+		dev_dbg(dev->class_dev, "no driver attached\n");
+		rc = -ENODEV;
+	} else {
+		rc = do_insn_ioctl(dev, &insn, file);
+	}
 	mutex_unlock(&dev->mutex);
 	return rc;
 }
@@ -3299,18 +3386,7 @@ static const struct file_operations comedi_fops = {
 	.llseek = noop_llseek,
 };
 
-/**
- * comedi_event() - Handle events for asynchronous COMEDI command
- * @dev: COMEDI device.
- * @s: COMEDI subdevice.
- * Context: in_interrupt() (usually), @s->spin_lock spin-lock not held.
- *
- * If an asynchronous COMEDI command is active on the subdevice, process
- * any %COMEDI_CB_... event flags that have been set, usually by an
- * interrupt handler.  These may change the run state of the asynchronous
- * command, wake a task, and/or send a %SIGIO signal.
- */
-void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
+void _comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
 {
 	struct comedi_async *async = s->async;
 	unsigned int events;
@@ -3346,6 +3422,25 @@ void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
 	if (si_code)
 		kill_fasync(&dev->async_queue, SIGIO, si_code);
 }
+
+/**
+ * comedi_event() - Handle events for asynchronous COMEDI command
+ * @dev: COMEDI device.
+ * @s: COMEDI subdevice.
+ * Context: in_interrupt() (usually), @s->spin_lock spin-lock not held.
+ *
+ * If an asynchronous COMEDI command is active on the subdevice, process
+ * any %COMEDI_CB_... event flags that have been set, usually by an
+ * interrupt handler.  These may change the run state of the asynchronous
+ * command, wake a task, and/or send a %SIGIO signal.
+ */
+void comedi_event(struct comedi_device *dev, struct comedi_subdevice *s)
+{
+	if (comedi_get_is_subdevice_running(s)) {
+		comedi_event(dev, s);
+		comedi_put_is_subdevice_running(s);
+	}
+}
 EXPORT_SYMBOL_GPL(comedi_event);
 
 /* Note: the ->mutex is pre-locked on successful return */
diff --git a/drivers/comedi/comedi_internal.h b/drivers/comedi/comedi_internal.h
index cf10ba016ebc..41a3b09f8f05 100644
--- a/drivers/comedi/comedi_internal.h
+++ b/drivers/comedi/comedi_internal.h
@@ -36,6 +36,18 @@ struct comedi_buf_map *
 comedi_buf_map_from_subdev_get(struct comedi_subdevice *s);
 unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s);
 unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s);
+unsigned int _comedi_buf_write_alloc(struct comedi_subdevice *s,
+				     unsigned int nbytes);
+unsigned int _comedi_buf_write_free(struct comedi_subdevice *s,
+				    unsigned int nbytes);
+unsigned int _comedi_buf_read_n_available(struct comedi_subdevice *s);
+unsigned int _comedi_buf_read_alloc(struct comedi_subdevice *s,
+				    unsigned int nbytes);
+unsigned int _comedi_buf_read_free(struct comedi_subdevice *s,
+				   unsigned int nbytes);
+void _comedi_inc_scan_progress(struct comedi_subdevice *s,
+			       unsigned int num_bytes);
+void _comedi_event(struct comedi_device *dev, struct comedi_subdevice *s);
 void comedi_device_cancel_all(struct comedi_device *dev);
 bool comedi_can_auto_free_spriv(struct comedi_subdevice *s);
 
diff --git a/drivers/comedi/drivers.c b/drivers/comedi/drivers.c
index c9ebaadc5e82..69cd2a253c66 100644
--- a/drivers/comedi/drivers.c
+++ b/drivers/comedi/drivers.c
@@ -441,6 +441,13 @@ unsigned int comedi_bytes_per_scan_cmd(struct comedi_subdevice *s,
 }
 EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
 
+static unsigned int _comedi_bytes_per_scan(struct comedi_subdevice *s)
+{
+	struct comedi_cmd *cmd = &s->async->cmd;
+
+	return comedi_bytes_per_scan_cmd(s, cmd);
+}
+
 /**
  * comedi_bytes_per_scan() - Get length of asynchronous command "scan" in bytes
  * @s: COMEDI subdevice.
@@ -458,9 +465,16 @@ EXPORT_SYMBOL_GPL(comedi_bytes_per_scan_cmd);
  */
 unsigned int comedi_bytes_per_scan(struct comedi_subdevice *s)
 {
-	struct comedi_cmd *cmd = &s->async->cmd;
+	unsigned int num_bytes;
 
-	return comedi_bytes_per_scan_cmd(s, cmd);
+	if (comedi_get_is_subdevice_running(s)) {
+		num_bytes = _comedi_bytes_per_scan(s);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		/* Use nomimal, single sample scan length. */
+		num_bytes = comedi_samples_to_bytes(s, 1);
+	}
+	return num_bytes;
 }
 EXPORT_SYMBOL_GPL(comedi_bytes_per_scan);
 
@@ -482,6 +496,17 @@ static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
 	return nscans;
 }
 
+static unsigned int _comedi_nscans_left(struct comedi_subdevice *s,
+					unsigned int nscans)
+{
+	if (nscans == 0) {
+		unsigned int nbytes = _comedi_buf_read_n_available(s);
+
+		nscans = nbytes / _comedi_bytes_per_scan(s);
+	}
+	return __comedi_nscans_left(s, nscans);
+}
+
 /**
  * comedi_nscans_left() - Return the number of scans left in the command
  * @s: COMEDI subdevice.
@@ -499,25 +524,18 @@ static unsigned int __comedi_nscans_left(struct comedi_subdevice *s,
 unsigned int comedi_nscans_left(struct comedi_subdevice *s,
 				unsigned int nscans)
 {
-	if (nscans == 0) {
-		unsigned int nbytes = comedi_buf_read_n_available(s);
-
-		nscans = nbytes / comedi_bytes_per_scan(s);
+	if (comedi_get_is_subdevice_running(s)) {
+		nscans = _comedi_nscans_left(s, nscans);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nscans = 0;
 	}
-	return __comedi_nscans_left(s, nscans);
+	return nscans;
 }
 EXPORT_SYMBOL_GPL(comedi_nscans_left);
 
-/**
- * comedi_nsamples_left() - Return the number of samples left in the command
- * @s: COMEDI subdevice.
- * @nsamples: The expected number of samples.
- *
- * Returns the number of samples remaining to complete the command, or the
- * specified expected number of samples (@nsamples), whichever is fewer.
- */
-unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
-				  unsigned int nsamples)
+static unsigned int _comedi_nsamples_left(struct comedi_subdevice *s,
+					  unsigned int nsamples)
 {
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
@@ -538,24 +556,34 @@ unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
 		return samples_left;
 	return nsamples;
 }
-EXPORT_SYMBOL_GPL(comedi_nsamples_left);
 
 /**
- * comedi_inc_scan_progress() - Update scan progress in asynchronous command
+ * comedi_nsamples_left() - Return the number of samples left in the command
  * @s: COMEDI subdevice.
- * @num_bytes: Amount of data in bytes to increment scan progress.
+ * @nsamples: The expected number of samples.
  *
- * Increments the scan progress by the number of bytes specified by @num_bytes.
- * If the scan progress reaches or exceeds the scan length in bytes, reduce
- * it modulo the scan length in bytes and set the "end of scan" asynchronous
- * event flag (%COMEDI_CB_EOS) to be processed later.
+ * Returns the number of samples remaining to complete the command, or the
+ * specified expected number of samples (@nsamples), whichever is fewer.
  */
-void comedi_inc_scan_progress(struct comedi_subdevice *s,
-			      unsigned int num_bytes)
+unsigned int comedi_nsamples_left(struct comedi_subdevice *s,
+				  unsigned int nsamples)
+{
+	if (comedi_get_is_subdevice_running(s)) {
+		nsamples = _comedi_nsamples_left(s, nsamples);
+		comedi_put_is_subdevice_running(s);
+	} else {
+		nsamples = 0;
+	}
+	return nsamples;
+}
+EXPORT_SYMBOL_GPL(comedi_nsamples_left);
+
+void _comedi_inc_scan_progress(struct comedi_subdevice *s,
+			       unsigned int num_bytes)
 {
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
-	unsigned int scan_length = comedi_bytes_per_scan(s);
+	unsigned int scan_length = _comedi_bytes_per_scan(s);
 
 	/* track the 'cur_chan' for non-SDF_PACKED subdevices */
 	if (!(s->subdev_flags & SDF_PACKED)) {
@@ -576,8 +604,43 @@ void comedi_inc_scan_progress(struct comedi_subdevice *s,
 		async->events |= COMEDI_CB_EOS;