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firewire: get_cycle_timer optimization and cleanup

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ohci:  Break out of the retry loop if too many attempts were necessary.
This may theoretically happen if the chip is fatally defective or if the
get_cycle_timer ioctl was performed after a CardBus controller was
ejected.

Also micro-optimize the loop by re-using the last two register reads in
the next iteration, remove a questionable inline keyword, and shuffle a
comment around.

core:  ioctl_get_cycle_timer() is always called with interrupts on,
therefore local_irq_save() can be replaced by local_irq_disable().
Disabled local IRQs imply disabled preemption, hence preempt_disable()
can be removed.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter
2010-02-20 22:24:43 +01:00
parent 1c1517efe1
commit 4a9bde9b8a
2 changed files with 36 additions and 37 deletions
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16
drivers/firewire/core-cdev.c
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@ -25,6 +25,7 @@
#include <linux/firewire.h>
#include <linux/firewire-cdev.h>
#include <linux/idr.h>
#include <linux/irqflags.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
@ -32,7 +33,6 @@
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/preempt.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/time.h>
@ -1013,21 +1013,19 @@ static int ioctl_get_cycle_timer(struct client *client, void *buffer)
{
struct fw_cdev_get_cycle_timer *request = buffer;
struct fw_card *card = client->device->card;
unsigned long long bus_time;
struct timeval tv;
unsigned long flags;
u32 cycle_time;
preempt_disable();
local_irq_save(flags);
local_irq_disable();
bus_time = card->driver->get_bus_time(card);
cycle_time = card->driver->get_bus_time(card);
do_gettimeofday(&tv);
local_irq_restore(flags);
preempt_enable();
local_irq_enable();
request->local_time = tv.tv_sec * 1000000ULL + tv.tv_usec;
request->cycle_timer = bus_time & 0xffffffff;
request->cycle_timer = cycle_time;
return 0;
}