mm: mmu_notifier: fix and extend kerneldoc

Fix W=1 compile warnings (invalid kerneldoc):

    mm/mmu_notifier.c:187: warning: Function parameter or member 'interval_sub' not described in 'mmu_interval_read_bgin'
    mm/mmu_notifier.c:708: warning: Function parameter or member 'subscription' not described in 'mmu_notifier_registr'
    mm/mmu_notifier.c:708: warning: Excess function parameter 'mn' description in 'mmu_notifier_register'
    mm/mmu_notifier.c:880: warning: Function parameter or member 'subscription' not described in 'mmu_notifier_put'
    mm/mmu_notifier.c:880: warning: Excess function parameter 'mn' description in 'mmu_notifier_put'
    mm/mmu_notifier.c:982: warning: Function parameter or member 'ops' not described in 'mmu_interval_notifier_insert'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: http://lkml.kernel.org/r/20200728171109.28687-4-krzk@kernel.orgSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/mmu_notifier.c

@@ -166,7 +166,7 @@ static void mn_itree_inv_end(struct mmu_notifier_subscriptions *subscriptions)
 /**
  * mmu_interval_read_begin - Begin a read side critical section against a VA
  *                           range
- * interval_sub: The interval subscription
+ * @interval_sub: The interval subscription
  *
  * mmu_iterval_read_begin()/mmu_iterval_read_retry() implement a
  * collision-retry scheme similar to seqcount for the VA range under
@@ -686,7 +686,7 @@ EXPORT_SYMBOL_GPL(__mmu_notifier_register);
 
 /**
  * mmu_notifier_register - Register a notifier on a mm
- * @mn: The notifier to attach
+ * @subscription: The notifier to attach
  * @mm: The mm to attach the notifier to
  *
  * Must not hold mmap_lock nor any other VM related lock when calling
@@ -856,7 +856,7 @@ static void mmu_notifier_free_rcu(struct rcu_head *rcu)
 
 /**
  * mmu_notifier_put - Release the reference on the notifier
- * @mn: The notifier to act on
+ * @subscription: The notifier to act on
  *
  * This function must be paired with each mmu_notifier_get(), it releases the
  * reference obtained by the get. If this is the last reference then process
@@ -965,7 +965,8 @@ static int __mmu_interval_notifier_insert(
  * @interval_sub: Interval subscription to register
  * @start: Starting virtual address to monitor
  * @length: Length of the range to monitor
- * @mm : mm_struct to attach to
+ * @mm: mm_struct to attach to
+ * @ops: Interval notifier operations to be called on matching events
  *
  * This function subscribes the interval notifier for notifications from the
  * mm.  Upon return the ops related to mmu_interval_notifier will be called