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[PATCH] shpchp: fix improper wait for command completion

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Current SHPCHP driver uses msleep_interruptible() function to wait for
a command completion event. But I think this would cause an unnecessary
long wait until timeout, if command completion interrupt came before
task state was changed to TASK_INTERRUPTIBLE. This patch fixes this
issue. With this patch, command completion becomes faster as follows:

o Without this patch

	# time echo 1 > power

	real    0m4.708s
	user    0m0.000s
	sys     0m0.524s

o With this patch

	# time echo 1 > power

	real    0m2.221s
	user    0m0.000s
	sys     0m0.532s

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Kenji Kaneshige
2005-11-25 12:28:53 +09:00
committed by Greg Kroah-Hartman
parent f467f6187f
commit bd62e27140
3 changed files with 27 additions and 37 deletions
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26
drivers/pci/hotplug/shpchp_hpc.c
View File

@@ -275,6 +275,25 @@ static void start_int_poll_timer(struct php_ctlr_state_s *php_ctlr, int seconds)
return;
}
static inline int shpc_wait_cmd(struct controller *ctrl)
{
int retval = 0;
unsigned int timeout_msec = shpchp_poll_mode ? 2000 : 1000;
unsigned long timeout = msecs_to_jiffies(timeout_msec);
int rc = wait_event_interruptible_timeout(ctrl->queue,
!ctrl->cmd_busy, timeout);
if (!rc) {
retval = -EIO;
err("Command not completed in %d msec\n", timeout_msec);
} else if (rc < 0) {
retval = -EINTR;
info("Command was interrupted by a signal\n");
}
ctrl->cmd_busy = 0;
return retval;
}
static int shpc_write_cmd(struct slot *slot, u8 t_slot, u8 cmd)
{
struct php_ctlr_state_s *php_ctlr = slot->ctrl->hpc_ctlr_handle;
@@ -314,8 +333,14 @@ static int shpc_write_cmd(struct slot *slot, u8 t_slot, u8 cmd)
/* To make sure the Controller Busy bit is 0 before we send out the
* command.
*/
slot->ctrl->cmd_busy = 1;
writew(temp_word, php_ctlr->creg + CMD);
/*
* Wait for command completion.
*/
retval = shpc_wait_cmd(slot->ctrl);
DBG_LEAVE_ROUTINE
return retval;
}
@@ -1064,6 +1089,7 @@ static irqreturn_t shpc_isr(int IRQ, void *dev_id, struct pt_regs *regs)
temp_dword = readl(php_ctlr->creg + SERR_INTR_ENABLE);
temp_dword &= 0xfffdffff;
writel(temp_dword, php_ctlr->creg + SERR_INTR_ENABLE);
ctrl->cmd_busy = 0;
wake_up_interruptible(&ctrl->queue);
}