IB/ipath: Change get_user_pages() usage to always NULL vmas

The static helper routine, __ipath_get_user_pages(), accepts a vma
arg, but current use always passes NULL.

This has caused some confusion associated with the correct use of this
argument, but since the current use case doesn't require the
flexiblity, the best thing to do is to simplfy the code to always pass
NULL to get_user_pages().

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/ipath/ipath_user_pages.c

@@ -54,7 +54,7 @@ static void __ipath_release_user_pages(struct page **p, size_t num_pages,
 
 /* call with current->mm->mmap_sem held */
 static int __ipath_get_user_pages(unsigned long start_page, size_t num_pages,
-				  struct page **p, struct vm_area_struct **vma)
+				  struct page **p)
 {
 	unsigned long lock_limit;
 	size_t got;
@@ -74,7 +74,7 @@ static int __ipath_get_user_pages(unsigned long start_page, size_t num_pages,
 		ret = get_user_pages(current, current->mm,
 				     start_page + got * PAGE_SIZE,
 				     num_pages - got, 1, 1,
-				     p + got, vma);
+				     p + got, NULL);
 		if (ret < 0)
 			goto bail_release;
 	}
@@ -165,7 +165,7 @@ int ipath_get_user_pages(unsigned long start_page, size_t num_pages,
 
 	down_write(&current->mm->mmap_sem);
 
-	ret = __ipath_get_user_pages(start_page, num_pages, p, NULL);
+	ret = __ipath_get_user_pages(start_page, num_pages, p);
 
 	up_write(&current->mm->mmap_sem);