tty: Fix lock order in tty_do_resize()

[mirror_ubuntu-artful-kernel.git] / include / linux / tty.h

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 8323ee4f95b9966afeb38f57e6685943f6e5e719..64f864651d8696aa5cf8a93b931c78c06a23bfdc 100644 (file)
--- 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 */
@@ -243,9 +243,11 @@ struct tty_struct {
 
        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 */
@@ -303,7 +305,6 @@ 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_OPEN         11      /* Line discipline is open */
 #define TTY_PTY_LOCK           16      /* pty private */