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Glibc was switched to the FUTEX_WAIT_BITSET op and CLOCK_REALTIME

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flag has been added instead of FUTEX_WAIT to replace the FUTEX_WAIT
logic which needs to do gettimeofday() calls before the futex syscall
to convert the absolute timeout to a relative timeout.
Before this the CLOCK_MONOTONIC used by the FUTEX_WAIT_BITSET op.

When the FUTEX_CLOCK_REALTIME is specified the timeout is an absolute
time, not a relative time. Rework futex_wait to handle this.
On the side fix the futex leak in error case and remove useless
parentheses.

Properly calculate the timeout for the CLOCK_MONOTONIC case.

MFC after:	3 days
This commit is contained in:
Dmitry Chagin 2014-05-31 14:58:53 +00:00
parent 34aa2211e7
commit fb6bf8bba9
1 changed files with 40 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

71
sys/compat/linux/linux_futex.c
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@ -128,9 +128,7 @@ LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
"struct waiting_proc *", "uint32_t");
LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
"struct waiting_proc **", "struct l_timespec *", "uint32_t");
LIN_SDT_PROBE_DEFINE1(futex, futex_wait, copyin_error, "int");
LIN_SDT_PROBE_DEFINE1(futex, futex_wait, itimerfix_error, "int");
"struct waiting_proc **", "int", "uint32_t");
LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
@ -144,6 +142,7 @@ LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
"struct linux_sys_futex_args *");
LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int");
LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
@ -554,15 +553,12 @@ futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
}
static int
futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts,
futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz,
uint32_t bitset)
{
struct l_timespec timeout;
struct timeval tv;
int timeout_hz;
int error;
LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset);
LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset);
if (bitset == 0) {
LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
@ -570,30 +566,9 @@ futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts,
}
f->f_bitset = bitset;
if (ts != NULL) {
error = copyin(ts, &timeout, sizeof(timeout));
if (error) {
LIN_SDT_PROBE1(futex, futex_wait, copyin_error, error);
LIN_SDT_PROBE1(futex, futex_wait, return, error);
return (error);
}
TIMESPEC_TO_TIMEVAL(&tv, &timeout);
error = itimerfix(&tv);
if (error) {
LIN_SDT_PROBE1(futex, futex_wait, itimerfix_error,
error);
LIN_SDT_PROBE1(futex, futex_wait, return, error);
return (error);
}
timeout_hz = tvtohz(&tv);
} else
timeout_hz = 0;
error = futex_sleep(f, wp, timeout_hz);
if (error) {
if (error)
LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
}
if (error == EWOULDBLOCK)
error = ETIMEDOUT;
@ -683,6 +658,9 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
struct linux_emuldata *em;
struct waiting_proc *wp;
struct futex *f, *f2;
struct l_timespec timeout;
struct timeval utv, ctv;
int timeout_hz;
int error;
uint32_t flags, val;
@ -756,7 +734,38 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
return (EWOULDBLOCK);
}
error = futex_wait(f, wp, args->timeout, args->val3);
if (args->timeout != NULL) {
error = copyin(args->timeout, &timeout, sizeof(timeout));
if (error) {
LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
error);
LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
futex_put(f, wp);
return (error);
}
TIMESPEC_TO_TIMEVAL(&utv, &timeout);
error = itimerfix(&utv);
if (error) {
LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error,
error);
LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
futex_put(f, wp);
return (error);
}
if (clockrt) {
microtime(&ctv);
timevalsub(&utv, &ctv);
} else if (args->op == LINUX_FUTEX_WAIT_BITSET) {
microuptime(&ctv);
timevalsub(&utv, &ctv);
}
if (utv.tv_sec < 0)
timevalclear(&utv);
timeout_hz = tvtohz(&utv);
} else
timeout_hz = 0;
error = futex_wait(f, wp, timeout_hz, args->val3);
break;
case LINUX_FUTEX_WAKE: