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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>
This commit is contained in:
Jiri Slaby 2012-03-05 14:52:17 +01:00 committed by Greg Kroah-Hartman
parent d852256389
commit 964105b501
2 changed files with 7 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
arch/ia64/hp/sim/simserial.c
View File

@ -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;

2
include/linux/serialP.h
View File

@ -56,8 +56,6 @@ struct async_struct {
wait_queue_head_t open_wait;
wait_queue_head_t close_wait;
wait_queue_head_t delta_msr_wait;
struct async_struct *next_port; /* For the linked list */
struct async_struct *prev_port;
};
#endif /* _LINUX_SERIAL_H */