From: Steven Rostedt <[email protected]>

Instead of hard coding 30 for the number of bits used for the static
buffer ids in two places, create a macro. This way if it changes in the
future, it will change in all the locations that use it.

Signed-off-by: Steven Rostedt <[email protected]>
---
 kernel/trace/ring_buffer.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 220b8405adfc..b88c75b52e8f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -335,6 +335,9 @@ static __always_inline unsigned int 
rb_read_page_capacity(struct buffer_data_rea
        return (PAGE_SIZE << rpage->order) - BUF_PAGE_HDR_SIZE;
 }
 
+/* The number of bits for static buffer ids */
+#define RB_STATIC_BITS 30
+
 /*
  * Note, the buffer_page list must be first. The buffer pages
  * are allocated in cache lines, which means that each buffer
@@ -350,7 +353,7 @@ struct buffer_page {
        local_t          entries;       /* entries on this page */
        unsigned long    real_end;      /* real end of data */
        unsigned         order;         /* order of the page */
-       u32              id:30;         /* ID for external mapping */
+       u32              id:RB_STATIC_BITS; /* ID for external mapping */
        u32              range:1;       /* Mapped via a range */
        struct buffer_data_page *page;  /* Actual data page */
 };
@@ -663,7 +666,7 @@ static unsigned long rb_static_max_pages(void)
         * Static ring buffers are using bpage::id and must account for the
         * reader page.
         */
-       return (1UL << 30) - 1;
+       return (1UL << RB_STATIC_BITS) - 1;
 }
 
 struct ring_buffer_iter {
-- 
2.53.0


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