Fix misspellings of "invocation" in comments.

Some comments misspell "invocation"; this fixes them. No code
changes.
Signed-off-by: NAdam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

fs/buffer.c

@@ -2893,7 +2893,7 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
 
 	/*
 	 * The page straddles i_size.  It must be zeroed out on each and every
-	 * writepage invokation because it may be mmapped.  "A file is mapped
+	 * writepage invocation because it may be mmapped.  "A file is mapped
 	 * in multiples of the page size.  For a file that is not a multiple of
 	 * the  page size, the remaining memory is zeroed when mapped, and
 	 * writes to that region are not written out to the file."

fs/mpage.c

@@ -561,7 +561,7 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
 	if (page->index >= end_index) {
 		/*
 		 * The page straddles i_size.  It must be zeroed out on each
-		 * and every writepage invokation because it may be mmapped.
+		 * and every writepage invocation because it may be mmapped.
 		 * "A file is mapped in multiples of the page size.  For a file
 		 * that is not a multiple of the page size, the remaining memory
 		 * is zeroed when mapped, and writes to that region are not

include/linux/mmzone.h

@@ -349,7 +349,7 @@ struct zone {
 	 * prev_priority holds the scanning priority for this zone.  It is
 	 * defined as the scanning priority at which we achieved our reclaim
 	 * target at the previous try_to_free_pages() or balance_pgdat()
-	 * invokation.
+	 * invocation.
 	 *
 	 * We use prev_priority as a measure of how much stress page reclaim is
 	 * under - it drives the swappiness decision: whether to unmap mapped

kernel/sched_cpupri.c

@@ -58,7 +58,7 @@ static int convert_prio(int prio)
  * @lowest_mask: A mask to fill in with selected CPUs (or NULL)
  *
  * Note: This function returns the recommended CPUs as calculated during the
- * current invokation.  By the time the call returns, the CPUs may have in
+ * current invocation.  By the time the call returns, the CPUs may have in
  * fact changed priorities any number of times.  While not ideal, it is not
  * an issue of correctness since the normal rebalancer logic will correct
  * any discrepancies created by racing against the uncertainty of the current