tty: Compute flip buffer ptrs

The char_buf_ptr and flag_buf_ptr values are trivially derived from
the .data field offset; compute values as needed.

Fixes a long-standing type-mismatch with the char and flag ptrs.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 12 insertions, 4 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 57a70d1d0412..87bbaa31ebf5 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -31,8 +31,6 @@
 
 struct tty_buffer {
         struct tty_buffer *next;
-        char *char_buf_ptr;
-        unsigned char *flag_buf_ptr;
         int used;
         int size;
         int commit;
@@ -41,6 +39,16 @@ struct tty_buffer {
         unsigned long data[0];
 };
 
+static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
+{
+        return ((unsigned char *)b->data) + ofs;
+}
+
+static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
+{
+        return (char *)char_buf_ptr(b, ofs) + b->size;
+}
+
 /*
  * We default to dicing tty buffer allocations to this many characters
  * in order to avoid multiple page allocations. We know the size of
diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index e0f252633b47..ad0303994c32 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -18,8 +18,8 @@ static inline int tty_insert_flip_char(struct tty_port *port,
 {
         struct tty_buffer *tb = port->buf.tail;
         if (tb && tb->used < tb->size) {
-                tb->flag_buf_ptr[tb->used] = flag;
-                tb->char_buf_ptr[tb->used++] = ch;
+                *flag_buf_ptr(tb, tb->used) = flag;
+                *char_buf_ptr(tb, tb->used++) = ch;
                 return 1;
         }
         return tty_insert_flip_string_flags(port, &ch, &flag, 1);