1 files changed, 39 insertions, 27 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 01ac30efd6a6..64f864651d86 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -10,6 +10,8 @@
 #include <linux/mutex.h>
 #include <linux/tty_flags.h>
 #include <uapi/linux/tty.h>
+#include <linux/rwsem.h>
+#include <linux/llist.h>
 
 
 
@@ -29,9 +31,10 @@
 #define __DISABLED_CHAR '\0'
 
 struct tty_buffer {
-        struct tty_buffer *next;
-        char *char_buf_ptr;
-        unsigned char *flag_buf_ptr;
+        union {
+                struct tty_buffer *next;
+                struct llist_node free;
+        };
         int used;
         int size;
         int commit;
@@ -40,25 +43,25 @@ struct tty_buffer {
         unsigned long data[0];
 };
 
-/*
- * We default to dicing tty buffer allocations to this many characters
- * in order to avoid multiple page allocations. We know the size of
- * tty_buffer itself but it must also be taken into account that the
- * the buffer is 256 byte aligned. See tty_buffer_find for the allocation
- * logic this must match
- */
-
-#define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)
+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 work_struct work;
-        spinlock_t lock;
         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           memory_used; /* In-use buffers excluding free list */
         struct tty_buffer *tail;        /* Active buffer */
-        struct tty_buffer *free;        /* Free queue head */
-        int memory_used;                /* Buffer space used excluding
-                                                                free queue */
 };
 /*
  * When a break, frame error, or parity error happens, these codes are
@@ -199,9 +202,6 @@ struct tty_port {
         wait_queue_head_t       close_wait;     /* Close waiters */
         wait_queue_head_t       delta_msr_wait; /* Modem status change */
         unsigned long           flags;          /* TTY flags ASY_*/
-        unsigned long           iflags;         /* TTYP_ internal flags */
-#define TTYP_FLUSHING                   1  /* Flushing to ldisc in progress */
-#define TTYP_FLUSHPENDING               2  /* Queued buffer flush pending */
         unsigned char           console:1,      /* port is a console */
                                 low_latency:1;  /* direct buffer flush */
         struct mutex            mutex;          /* Locking */
@@ -238,14 +238,16 @@ struct tty_struct {
         int index;
 
         /* Protects ldisc changes: Lock tty not pty */
-        struct mutex ldisc_mutex;
+        struct ld_semaphore ldisc_sem;
         struct tty_ldisc *ldisc;
 
         struct mutex atomic_write_lock;
         struct mutex legacy_mutex;
-        struct mutex termios_mutex;
+        struct mutex throttle_mutex;
+        struct rw_semaphore termios_rwsem;
+        struct mutex winsize_mutex;
         spinlock_t ctrl_lock;
-        /* Termios values are protected by the termios mutex */
+        /* Termios values are protected by the termios rwsem */
         struct ktermios termios, termios_locked;
         struct termiox *termiox;        /* May be NULL for unsupported */
         char name[64];
@@ -253,7 +255,7 @@ struct tty_struct {
         struct pid *session;
         unsigned long flags;
         int count;
-        struct winsize winsize;         /* termios mutex */
+        struct winsize winsize;         /* winsize_mutex */
         unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
         unsigned char ctrl_status;      /* ctrl_lock */
         unsigned int receive_room;      /* Bytes free for queue */
@@ -303,10 +305,7 @@ struct tty_file_private {
 #define TTY_EXCLUSIVE           3       /* Exclusive open mode */
 #define TTY_DEBUG               4       /* Debugging */
 #define TTY_DO_WRITE_WAKEUP     5       /* Call write_wakeup after queuing new */
-#define TTY_PUSH                6       /* n_tty private */
 #define TTY_CLOSING             7       /* ->close() in progress */
-#define TTY_LDISC               9       /* Line discipline attached */
-#define TTY_LDISC_CHANGING      10      /* Line discipline changing */
 #define TTY_LDISC_OPEN          11      /* Line discipline is open */
 #define TTY_PTY_LOCK            16      /* pty private */
 #define TTY_NO_WRITE_SPLIT      17      /* Preserve write boundaries to driver */
@@ -559,6 +558,19 @@ extern void tty_ldisc_init(struct tty_struct *tty);
 extern void tty_ldisc_deinit(struct tty_struct *tty);
 extern void tty_ldisc_begin(void);
 
+static inline int tty_ldisc_receive_buf(struct tty_ldisc *ld, unsigned char *p,
+                                        char *f, int count)
+{
+        if (ld->ops->receive_buf2)
+                count = ld->ops->receive_buf2(ld->tty, p, f, count);
+        else {
+                count = min_t(int, count, ld->tty->receive_room);
+                if (count)
+                        ld->ops->receive_buf(ld->tty, p, f, count);
+        }
+        return count;
+}
+
 
 /* n_tty.c */
 extern struct tty_ldisc_ops tty_ldisc_N_TTY;