[PATCH 2/2] let-message-queue-timeout-use-hrtimer.patch

From: Carsten Emde
Date: Fri Apr 02 2010 - 16:49:00 EST


The message queue functions mq_timedsend() and mq_timedreceive()
have not yet been converted to use the hrtimer interface.

This patch replaces the call to schedule_timeout() by a call to
schedule_hrtimeout() and transforms the expiration time from
timespec to ktime as required.

CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Arjan van de Veen <arjan@xxxxxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Pradyumna Sampath <pradysam@xxxxxxxxx>
Signed-off-by: Carsten Emde <C.Emde@xxxxxxxxx>

---
ipc/mqueue.c | 74 +++++++++++++++++++----------------------------------------
1 file changed, 25 insertions(+), 49 deletions(-)

Index: head/ipc/mqueue.c
===================================================================
--- head.orig/ipc/mqueue.c
+++ head/ipc/mqueue.c
@@ -428,7 +428,7 @@ static void wq_add(struct mqueue_inode_i
* sr: SEND or RECV
*/
static int wq_sleep(struct mqueue_inode_info *info, int sr,
- long timeout, struct ext_wait_queue *ewp)
+ ktime_t *timeout, struct ext_wait_queue *ewp)
{
int retval;
signed long time;
@@ -439,7 +439,8 @@ static int wq_sleep(struct mqueue_inode_
set_current_state(TASK_INTERRUPTIBLE);

spin_unlock(&info->lock);
- time = schedule_timeout(timeout);
+ time = schedule_hrtimeout_range_clock(timeout,
+ HRTIMER_MODE_ABS, 0, CLOCK_REALTIME);

while (ewp->state == STATE_PENDING)
cpu_relax();
@@ -551,31 +552,16 @@ static void __do_notify(struct mqueue_in
wake_up(&info->wait_q);
}

-static long prepare_timeout(struct timespec *p)
+static int prepare_timeout(const struct timespec __user *u_abs_timeout,
+ ktime_t *expires, struct timespec *ts)
{
- struct timespec nowts;
- long timeout;
-
- if (p) {
- if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
- || p->tv_nsec >= NSEC_PER_SEC))
- return -EINVAL;
- nowts = CURRENT_TIME;
- /* first subtract as jiffies can't be too big */
- p->tv_sec -= nowts.tv_sec;
- if (p->tv_nsec < nowts.tv_nsec) {
- p->tv_nsec += NSEC_PER_SEC;
- p->tv_sec--;
- }
- p->tv_nsec -= nowts.tv_nsec;
- if (p->tv_sec < 0)
- return 0;
-
- timeout = timespec_to_jiffies(p) + 1;
- } else
- return MAX_SCHEDULE_TIMEOUT;
+ if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
+ return -EFAULT;
+ if (!timespec_valid(ts))
+ return -EINVAL;

- return timeout;
+ *expires = timespec_to_ktime(*ts);
+ return 0;
}

static void remove_notification(struct mqueue_inode_info *info)
@@ -861,22 +847,21 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqd
struct ext_wait_queue *receiver;
struct msg_msg *msg_ptr;
struct mqueue_inode_info *info;
- struct timespec ts, *p = NULL;
- long timeout;
+ ktime_t expires, *timeout = NULL;
+ struct timespec ts;
int ret;

if (u_abs_timeout) {
- if (copy_from_user(&ts, u_abs_timeout,
- sizeof(struct timespec)))
- return -EFAULT;
- p = &ts;
+ int res = prepare_timeout(u_abs_timeout, &expires, &ts);
+ if (res)
+ return res;
+ timeout = &expires;
}

if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
return -EINVAL;

- audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
- timeout = prepare_timeout(p);
+ audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);

filp = fget(mqdes);
if (unlikely(!filp)) {
@@ -918,9 +903,6 @@ SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqd
if (filp->f_flags & O_NONBLOCK) {
spin_unlock(&info->lock);
ret = -EAGAIN;
- } else if (unlikely(timeout < 0)) {
- spin_unlock(&info->lock);
- ret = timeout;
} else {
wait.task = current;
wait.msg = (void *) msg_ptr;
@@ -953,24 +935,23 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t,
size_t, msg_len, unsigned int __user *, u_msg_prio,
const struct timespec __user *, u_abs_timeout)
{
- long timeout;
ssize_t ret;
struct msg_msg *msg_ptr;
struct file *filp;
struct inode *inode;
struct mqueue_inode_info *info;
struct ext_wait_queue wait;
- struct timespec ts, *p = NULL;
+ ktime_t expires, *timeout = NULL;
+ struct timespec ts;

if (u_abs_timeout) {
- if (copy_from_user(&ts, u_abs_timeout,
- sizeof(struct timespec)))
- return -EFAULT;
- p = &ts;
+ int res = prepare_timeout(u_abs_timeout, &expires, &ts);
+ if (res)
+ return res;
+ timeout = &expires;
}

- audit_mq_sendrecv(mqdes, msg_len, 0, p);
- timeout = prepare_timeout(p);
+ audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);

filp = fget(mqdes);
if (unlikely(!filp)) {
@@ -1002,11 +983,6 @@ SYSCALL_DEFINE5(mq_timedreceive, mqd_t,
if (filp->f_flags & O_NONBLOCK) {
spin_unlock(&info->lock);
ret = -EAGAIN;
- msg_ptr = NULL;
- } else if (unlikely(timeout < 0)) {
- spin_unlock(&info->lock);
- ret = timeout;
- msg_ptr = NULL;
} else {
wait.task = current;
wait.state = STATE_NONE;

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