tty: move tty_buffer definitions to new tty_buffer.h

tty.h is large enough currently. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_buffer.h and move there tty_buffer-related
declarations and function prototypes.

Note that many of the tty_buffer.c function prototypes reside now in
tty_flip.h. But we cannot move struct tty_buffer & friends because:
* tty_insert_flip_char() in tty_flip.h needs both struct tty_port and
  struct tty_buffer defined.
* struct tty_port in tty_port.h needs struct tty_buffer defined.

So if we moved struct tty_buffer to tty_flip.h too, tty_flip.h would
need tty_port.h and that would need tty_flip.h (to have tty_buffer)
again. Hence we introduce new header tty_buffer.h here to break this
circular dependency.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-7-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/tty.h b/include/linux/tty.h
index fad53f69a8caa10683eeb4e7131f2b71a4241914..b5f353797ceca636b4e8d66c9891f07a33f6a0e0 100644 (file)
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -6,6 +6,7 @@
 #include <linux/major.h>
 #include <linux/termios.h>
 #include <linux/workqueue.h>
+#include <linux/tty_buffer.h>
 #include <linux/tty_driver.h>
 #include <linux/tty_ldisc.h>
 #include <linux/mutex.h>
@@ -30,54 +31,6 @@
  */
 #define __DISABLED_CHAR '\0'
 
-struct tty_buffer {
-       union {
-               struct tty_buffer *next;
-               struct llist_node free;
-       };
-       int used;
-       int size;
-       int commit;
-       int read;
-       int flags;
-       /* Data points here */
-       unsigned long data[];
-};
-
-/* Values for .flags field of tty_buffer */
-#define TTYB_NORMAL    1       /* buffer has no flags buffer */
-
-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;
-}
-
-struct tty_bufhead {
-       struct tty_buffer *head;        /* Queue head */
-       struct work_struct work;
-       struct mutex       lock;
-       atomic_t           priority;
-       struct tty_buffer sentinel;
-       struct llist_head free;         /* Free queue head */
-       atomic_t           mem_used;    /* In-use buffers excluding free list */
-       int                mem_limit;
-       struct tty_buffer *tail;        /* Active buffer */
-};
-/*
- * When a break, frame error, or parity error happens, these codes are
- * stuffed into the flags buffer.
- */
-#define TTY_NORMAL     0
-#define TTY_BREAK      1
-#define TTY_FRAME      2
-#define TTY_PARITY     3
-#define TTY_OVERRUN    4
-
 #define INTR_CHAR(tty) ((tty)->termios.c_cc[VINTR])
 #define QUIT_CHAR(tty) ((tty)->termios.c_cc[VQUIT])
 #define ERASE_CHAR(tty) ((tty)->termios.c_cc[VERASE])

diff --git a/include/linux/tty_buffer.h b/include/linux/tty_buffer.h
new file mode 100644 (file)
index 0000000..3b9d776
--- /dev/null
+++ b/include/linux/tty_buffer.h
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_TTY_BUFFER_H
+#define _LINUX_TTY_BUFFER_H
+
+#include <linux/atomic.h>
+#include <linux/llist.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+struct tty_buffer {
+       union {
+               struct tty_buffer *next;
+               struct llist_node free;
+       };
+       int used;
+       int size;
+       int commit;
+       int read;
+       int flags;
+       /* Data points here */
+       unsigned long data[];
+};
+
+/* Values for .flags field of tty_buffer */
+#define TTYB_NORMAL    1       /* buffer has no flags buffer */
+
+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;
+}
+
+struct tty_bufhead {
+       struct tty_buffer *head;        /* Queue head */
+       struct work_struct work;
+       struct mutex       lock;
+       atomic_t           priority;
+       struct tty_buffer sentinel;
+       struct llist_head free;         /* Free queue head */
+       atomic_t           mem_used;    /* In-use buffers excluding free list */
+       int                mem_limit;
+       struct tty_buffer *tail;        /* Active buffer */
+};
+
+/*
+ * When a break, frame error, or parity error happens, these codes are
+ * stuffed into the flags buffer.
+ */
+#define TTY_NORMAL     0
+#define TTY_BREAK      1
+#define TTY_FRAME      2
+#define TTY_PARITY     3
+#define TTY_OVERRUN    4
+
+#endif