um: Use tty_port in SIGWINCH handler

The tty below tty_port might get destroyed by the tty layer
while we hold a reference to it.
So we have to carry tty_port around...

Signed-off-by: Richard Weinberger <richard@nod.at>

diff --git a/arch/um/drivers/chan.h b/arch/um/drivers/chan.h
index 78f1b899996446e9e769ff703938dbb7bedc6fe6..c512b0306dd41beff8039787d1eca7b90546ed40 100644 (file)
--- a/arch/um/drivers/chan.h
+++ b/arch/um/drivers/chan.h
@@ -37,7 +37,7 @@ extern int console_write_chan(struct chan *chan, const char *buf,
 extern int console_open_chan(struct line *line, struct console *co);
 extern void deactivate_chan(struct chan *chan, int irq);
 extern void reactivate_chan(struct chan *chan, int irq);
-extern void chan_enable_winch(struct chan *chan, struct tty_struct *tty);
+extern void chan_enable_winch(struct chan *chan, struct tty_port *port);
 extern int enable_chan(struct line *line);
 extern void close_chan(struct line *line);
 extern int chan_window_size(struct line *line, 

diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index 15c553c239a119259f2f948f8381e5a9a26f4ccb..80b47cb71e0a85e7ea1a10626f7a1e0efe8e5225 100644 (file)
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -122,10 +122,10 @@ static int open_chan(struct list_head *chans)
        return err;
 }
 
-void chan_enable_winch(struct chan *chan, struct tty_struct *tty)
+void chan_enable_winch(struct chan *chan, struct tty_port *port)
 {
        if (chan && chan->primary && chan->ops->winch)
-               register_winch(chan->fd, tty);
+               register_winch(chan->fd, port);
 }
 
 static void line_timer_cb(struct work_struct *work)

diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index 9be670ad23b5fa6c94bb6b361bb9db59a0924a2d..3fd7c3efdb18df6b0f8f1dfd68e3883052b329c1 100644 (file)
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -216,7 +216,7 @@ static int winch_thread(void *arg)
        }
 }
 
-static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out,
+static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
                       unsigned long *stack_out)
 {
        struct winch_data data;
@@ -271,7 +271,7 @@ static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out,
        return err;
 }
 
-void register_winch(int fd, struct tty_struct *tty)
+void register_winch(int fd, struct tty_port *port)
 {
        unsigned long stack;
        int pid, thread, count, thread_fd = -1;
@@ -281,17 +281,17 @@ void register_winch(int fd, struct tty_struct *tty)
                return;
 
        pid = tcgetpgrp(fd);
-       if (is_skas_winch(pid, fd, tty)) {
-               register_winch_irq(-1, fd, -1, tty, 0);
+       if (is_skas_winch(pid, fd, port)) {
+               register_winch_irq(-1, fd, -1, port, 0);
                return;
        }
 
        if (pid == -1) {
-               thread = winch_tramp(fd, tty, &thread_fd, &stack);
+               thread = winch_tramp(fd, port, &thread_fd, &stack);
                if (thread < 0)
                        return;
 
-               register_winch_irq(thread_fd, fd, thread, tty, stack);
+               register_winch_irq(thread_fd, fd, thread, port, stack);
 
                count = write(thread_fd, &c, sizeof(c));
                if (count != sizeof(c))

diff --git a/arch/um/drivers/chan_user.h b/arch/um/drivers/chan_user.h
index dc693298eb8fc0a73719d98521f8a4ae9f911dfa..03f1b565c5f9ac9028ed7b91444b89c1dde963f1 100644 (file)
--- a/arch/um/drivers/chan_user.h
+++ b/arch/um/drivers/chan_user.h
@@ -38,10 +38,10 @@ extern int generic_window_size(int fd, void *unused, unsigned short *rows_out,
                               unsigned short *cols_out);
 extern void generic_free(void *data);
 
-struct tty_struct;
-extern void register_winch(int fd,  struct tty_struct *tty);
+struct tty_port;
+extern void register_winch(int fd,  struct tty_port *port);
 extern void register_winch_irq(int fd, int tty_fd, int pid,
-                              struct tty_struct *tty, unsigned long stack);
+                              struct tty_port *port, unsigned long stack);
 
 #define __channel_help(fn, prefix) \
 __uml_help(fn, prefix "[0-9]*=<channel description>\n" \

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 232243aec70c1ded138780fd9d67241df0bb6dec..be541cf69fd282cea191a3580e851549f25c39e0 100644 (file)
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -305,7 +305,7 @@ static int line_activate(struct tty_port *port, struct tty_struct *tty)
                return ret;
 
        if (!line->sigio) {
-               chan_enable_winch(line->chan_out, tty);
+               chan_enable_winch(line->chan_out, port);
                line->sigio = 1;
        }
 
@@ -603,7 +603,7 @@ struct winch {
        int fd;
        int tty_fd;
        int pid;
-       struct tty_struct *tty;
+       struct tty_port *port;
        unsigned long stack;
        struct work_struct work;
 };
@@ -657,7 +657,7 @@ static irqreturn_t winch_interrupt(int irq, void *data)
                        goto out;
                }
        }
-       tty = winch->tty;
+       tty = tty_port_tty_get(winch->port);
        if (tty != NULL) {
                line = tty->driver_data;
                if (line != NULL) {
@@ -665,6 +665,7 @@ static irqreturn_t winch_interrupt(int irq, void *data)
                                         &tty->winsize.ws_col);
                        kill_pgrp(tty->pgrp, SIGWINCH, 1);
                }
+               tty_kref_put(tty);
        }
  out:
        if (winch->fd != -1)
@@ -672,7 +673,7 @@ static irqreturn_t winch_interrupt(int irq, void *data)
        return IRQ_HANDLED;
 }
 
-void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
+void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
                        unsigned long stack)
 {
        struct winch *winch;
@@ -687,7 +688,7 @@ void register_winch_irq(int fd, int tty_fd, int pid, struct tty_struct *tty,
                                   .fd          = fd,
                                   .tty_fd      = tty_fd,
                                   .pid         = pid,
-                                  .tty         = tty,
+                                  .port        = port,
                                   .stack       = stack });
 
        if (um_request_irq(WINCH_IRQ, fd, IRQ_READ, winch_interrupt,
@@ -716,15 +717,18 @@ static void unregister_winch(struct tty_struct *tty)
 {
        struct list_head *ele, *next;
        struct winch *winch;
+       struct tty_struct *wtty;
 
        spin_lock(&winch_handler_lock);
 
        list_for_each_safe(ele, next, &winch_handlers) {
                winch = list_entry(ele, struct winch, list);
-               if (winch->tty == tty) {
+               wtty = tty_port_tty_get(winch->port);
+               if (wtty == tty) {
                        free_winch(winch);
                        break;
                }
+               tty_kref_put(wtty);
        }
        spin_unlock(&winch_handler_lock);
 }