TTY: simserial, remove support of shared interrupts

It never worked there. The ISR was never written for that kind of
stuff. So remove all that crap with a hash of linked lists and pass
the pointer directly to the ISR.

BTW this answers the question there:
  * I don't know exactly why they don't use the dev_id opaque data
  * pointer instead of this extra lookup table

-> Because they thought they will support more devices bound to a
single interrupt w/o IRQF_SHARED. They would need exactly the hash
there.

What I don't understand is rebinding of the interrupt in the shutdown
path. They perhaps meant to do just synchronize_irq? In any case, this
is all gone and free_irq there properly.

By removing the hash we save some bits (exactly NR_IRQS * 8 bytes of
.bss and over a kilo of .text):
before:
   text    data     bss     dec     hex filename
  19600     320    8227   28147    6df3 ../a/ia64/arch/ia64/hp/sim/simserial.o
after:
   text    data     bss     dec     hex filename
  18568     320      28   18916    49e4 ../a/ia64/arch/ia64/hp/sim/simserial.o

Note that a shared interrupt could not work too. request_irq requires
data parameter to be non-NULL. So the whole IRQ_T exercise was
pointless.

Finally, this helps us remove another two members of async_struct :).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 57 deletions

diff --git a/arch/ia64/hp/sim/simserial.c b/arch/ia64/hp/sim/simserial.c
index d32b759b23f1..c35552df035e 100644
--- a/arch/ia64/hp/sim/simserial.c
+++ b/arch/ia64/hp/sim/simserial.c
@@ -92,8 +92,6 @@ static struct serial_uart_config uart_config[] = {
 
 struct tty_driver *hp_simserial_driver;
 
-static struct async_struct *IRQ_ports[NR_IRQS];
-
 static struct console *console;
 
 static unsigned char *tmp_buf;
@@ -167,14 +165,9 @@ static  void receive_chars(struct tty_struct *tty)
  */
 static irqreturn_t rs_interrupt_single(int irq, void *dev_id)
 {
-        struct async_struct * info;
+        struct async_struct *info = dev_id;
 
-        /*
-         * I don't know exactly why they don't use the dev_id opaque data
-         * pointer instead of this extra lookup table
-         */
-        info = IRQ_ports[irq];
-        if (!info || !info->tty) {
+        if (!info->tty) {
                 printk(KERN_INFO "simrs_interrupt_single: info|tty=0 info=%p problem\n", info);
                 return IRQ_NONE;
         }
@@ -456,7 +449,6 @@ static void shutdown(struct async_struct * info)
 {
         unsigned long   flags;
         struct serial_state *state = info->state;
-        int             retval;
 
         if (!(state->flags & ASYNC_INITIALIZED))
                 return;
@@ -468,33 +460,8 @@ static void shutdown(struct async_struct * info)
 
         local_irq_save(flags);
         {
-                /*
-                 * First unlink the serial port from the IRQ chain...
-                 */
-                if (info->next_port)
-                        info->next_port->prev_port = info->prev_port;
-                if (info->prev_port)
-                        info->prev_port->next_port = info->next_port;
-                else
-                        IRQ_ports[state->irq] = info->next_port;
-
-                /*
-                 * Free the IRQ, if necessary
-                 */
-                if (state->irq && (!IRQ_ports[state->irq] ||
-                                   !IRQ_ports[state->irq]->next_port)) {
-                        if (IRQ_ports[state->irq]) {
-                                free_irq(state->irq, NULL);
-                                retval = request_irq(state->irq, rs_interrupt_single,
-                                                     IRQ_T(state), "serial",
-                                                     NULL);
-
-                                if (retval)
-                                        printk(KERN_ERR "serial shutdown: request_irq: error %d"
-                                               "  Couldn't reacquire IRQ.\n", retval);
-                        } else
-                                free_irq(state->irq, NULL);
-                }
+                if (state->irq)
+                        free_irq(state->irq, info);
 
                 if (info->xmit.buf) {
                         free_page((unsigned long) info->xmit.buf);
@@ -645,7 +612,6 @@ startup(struct async_struct *info)
 {
         unsigned long flags;
         int     retval=0;
-        irq_handler_t handler;
         struct serial_state *state= info->state;
         unsigned long page;
 
@@ -677,29 +643,13 @@ startup(struct async_struct *info)
         /*
          * Allocate the IRQ if necessary
          */
-        if (state->irq && (!IRQ_ports[state->irq] ||
-                          !IRQ_ports[state->irq]->next_port)) {
-                if (IRQ_ports[state->irq]) {
-                        retval = -EBUSY;
-                        goto errout;
-                } else
-                        handler = rs_interrupt_single;
-
-                retval = request_irq(state->irq, handler, IRQ_T(state),
-                                "simserial", NULL);
+        if (state->irq) {
+                retval = request_irq(state->irq, rs_interrupt_single,
+                                IRQ_T(state), "simserial", info);
                 if (retval)
                         goto errout;
         }
 
-        /*
-         * Insert serial port into IRQ chain.
-         */
-        info->prev_port = NULL;
-        info->next_port = IRQ_ports[state->irq];
-        if (info->next_port)
-                info->next_port->prev_port = info;
-        IRQ_ports[state->irq] = info;
-
         if (info->tty) clear_bit(TTY_IO_ERROR, &info->tty->flags);
 
         info->xmit.head = info->xmit.tail = 0;