[RESEND PATCH] ring-buffer: Use vma_pages() helper function

[Thorsten Blum]

Use the vma_pages() helper function and fix the following
Coccinelle/coccicheck warning reported by vma_pages.cocci:

  WARNING: Consider using vma_pages helper on vma

Rename the local variable vma_pages accordingly.

Signed-off-by: Thorsten Blum <thorsten.b...@toblux.com>
---
 kernel/trace/ring_buffer.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 28853966aa9a..473ba56b889b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -6226,7 +6226,7 @@ static int __rb_inc_dec_mapped(struct ring_buffer_per_cpu 
*cpu_buffer,
 static int __rb_map_vma(struct ring_buffer_per_cpu *cpu_buffer,
                        struct vm_area_struct *vma)
 {
-       unsigned long nr_subbufs, nr_pages, vma_pages, pgoff = vma->vm_pgoff;
+       unsigned long nr_subbufs, nr_pages, nr_vma_pages, pgoff = vma->vm_pgoff;
        unsigned int subbuf_pages, subbuf_order;
        struct page **pages;
        int p = 0, s = 0;
@@ -6252,11 +6252,11 @@ static int __rb_map_vma(struct ring_buffer_per_cpu 
*cpu_buffer,
        nr_subbufs = cpu_buffer->nr_pages + 1; /* + reader-subbuf */
        nr_pages = ((nr_subbufs) << subbuf_order) - pgoff + 1; /* + meta-page */
 
-       vma_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
-       if (!vma_pages || vma_pages > nr_pages)
+       nr_vma_pages = vma_pages(vma);
+       if (!nr_vma_pages || nr_vma_pages > nr_pages)
                return -EINVAL;
 
-       nr_pages = vma_pages;
+       nr_pages = nr_vma_pages;
 
        pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
        if (!pages)
-- 
2.45.2