tty: We want the port object to be persistent

Move the tty_port and uart_info bits around a little. By embedding the uart_info
into the uart_port we get rid of lots of corner case testing and also get the
ability to go port<->state<->info which is a bit more elegant than the current
data structures.

Downsides - we allocate a tiny bit more memory for unused ports, upside we've
removed as much code as it saved for most users..

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 34 insertions, 28 deletions

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index feb3b939ec4b..2395969faa04 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -316,35 +316,13 @@ struct uart_port {
 };
 
 /*
- * This is the state information which is persistent across opens.
- * The low level driver must not to touch any elements contained
- * within.
- */
-struct uart_state {
-        unsigned int            close_delay;            /* msec */
-        unsigned int            closing_wait;           /* msec */
-
-#define USF_CLOSING_WAIT_INF    (0)
-#define USF_CLOSING_WAIT_NONE   (~0U)
-
-        int                     count;
-        int                     pm_state;
-        struct uart_info        *info;
-        struct uart_port        *port;
-
-        struct mutex            mutex;
-};
-
-#define UART_XMIT_SIZE  PAGE_SIZE
-
-typedef unsigned int __bitwise__ uif_t;
-
-/*
  * This is the state information which is only valid when the port
- * is open; it may be freed by the core driver once the device has
+ * is open; it may be cleared the core driver once the device has
  * been closed.  Either the low level driver or the core can modify
  * stuff here.
  */
+typedef unsigned int __bitwise__ uif_t;
+
 struct uart_info {
         struct tty_port         port;
         struct circ_buf         xmit;
@@ -366,6 +344,29 @@ struct uart_info {
         wait_queue_head_t       delta_msr_wait;
 };
 
+/*
+ * This is the state information which is persistent across opens.
+ * The low level driver must not to touch any elements contained
+ * within.
+ */
+struct uart_state {
+        unsigned int            close_delay;            /* msec */
+        unsigned int            closing_wait;           /* msec */
+
+#define USF_CLOSING_WAIT_INF    (0)
+#define USF_CLOSING_WAIT_NONE   (~0U)
+
+        int                     count;
+        int                     pm_state;
+        struct uart_info        info;
+        struct uart_port        *port;
+
+        struct mutex            mutex;
+};
+
+#define UART_XMIT_SIZE  PAGE_SIZE
+
+
 /* number of characters left in xmit buffer before we ask for more */
 #define WAKEUP_CHARS            256
 
@@ -439,8 +440,13 @@ int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
 #define uart_circ_chars_free(circ)      \
         (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
 
-#define uart_tx_stopped(portp)          \
-        ((portp)->info->port.tty->stopped || (portp)->info->port.tty->hw_stopped)
+static inline int uart_tx_stopped(struct uart_port *port)
+{
+        struct tty_struct *tty = port->info->port.tty;
+        if(tty->stopped || tty->hw_stopped)
+                return 1;
+        return 0;
+}
 
 /*
  * The following are helper functions for the low level drivers.
@@ -451,7 +457,7 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
 #ifdef SUPPORT_SYSRQ
         if (port->sysrq) {
                 if (ch && time_before(jiffies, port->sysrq)) {
-                        handle_sysrq(ch, port->info ? port->info->port.tty : NULL);
+                        handle_sysrq(ch, port->info->port.tty);
                         port->sysrq = 0;
                         return 1;
                 }