Date: Thu, 13 Sep 2012 01:07:11 +0100 From: Attilio Rao <attilio@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, Davide Italiano <davide@freebsd.org>, src-committers@freebsd.org, svn-src-projects@freebsd.org Subject: Re: svn commit: r238907 - projects/calloutng/sys/kern Message-ID: <CAJ-FndDnYE3CKNRajGn5YV4TBKDRCnX3=cgyT2yA9mxbnkangQ@mail.gmail.com> In-Reply-To: <201209121511.42296.jhb@freebsd.org> References: <201207301350.q6UDobCI099069@svn.freebsd.org> <504CF1FB.9090106@FreeBSD.org> <CAJ-FndCW91Y=SB3GFXDxtXGQdQzUzyF5KzKqjtuFYGs0W0-w6g@mail.gmail.com> <201209121511.42296.jhb@freebsd.org>
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On Wed, Sep 12, 2012 at 8:11 PM, John Baldwin <jhb@freebsd.org> wrote:
> On Monday, September 10, 2012 9:11:22 pm Attilio Rao wrote:
>> Speaking of which, I think it is time for curthread != NULL checks in
>> the locking primitives to go, or there is a good reason I really don't
>> understand to keep them?
>
> They can probably be axed.
What do you think about this?
Please note that I would also axe the check in printtrap() on several
arches, but maybe there is a valid reason to keep it I'm not thinking
right now, so I left it out in this patch.
Thanks,
Attilio
Subject: [PATCH 6/6] Remove all the checks on curthread != NULL with the
exception of MD in printtrap() functions on several
!x86 arches.
Generally this check is not needed anymore, as there is not
a legitimate case where curthread != NULL.
Discussed with: bde, jhb
---
sys/dev/hwpmc/hwpmc_arm.c | 6 ++----
sys/dev/hwpmc/hwpmc_x86.c | 3 +--
sys/kern/kern_condvar.c | 2 +-
sys/kern/kern_mutex.c | 5 -----
sys/kern/kern_rwlock.c | 2 --
sys/kern/kern_sx.c | 5 -----
sys/kern/kern_thread.c | 1 -
sys/kern/vfs_subr.c | 1 -
8 files changed, 4 insertions(+), 21 deletions(-)
diff --git a/sys/dev/hwpmc/hwpmc_arm.c b/sys/dev/hwpmc/hwpmc_arm.c
index c2c24c2..79613f7 100644
--- a/sys/dev/hwpmc/hwpmc_arm.c
+++ b/sys/dev/hwpmc/hwpmc_arm.c
@@ -78,8 +78,7 @@ pmc_save_kernel_callchain(uintptr_t *cc, int maxsamples,
pc = PMC_TRAPFRAME_TO_PC(tf);
*cc++ = pc;
- if ((td = curthread) == NULL)
- return (1);
+ td = curthread;
if (maxsamples <= 1)
return (1);
@@ -129,8 +128,7 @@ pmc_save_user_callchain(uintptr_t *cc, int maxsamples,
pc = PMC_TRAPFRAME_TO_PC(tf);
*cc++ = pc;
- if ((td = curthread) == NULL)
- return (1);
+ td = curthread;
if (maxsamples <= 1)
return (1);
diff --git a/sys/dev/hwpmc/hwpmc_x86.c b/sys/dev/hwpmc/hwpmc_x86.c
index e7485a4..cd9e4f6 100644
--- a/sys/dev/hwpmc/hwpmc_x86.c
+++ b/sys/dev/hwpmc/hwpmc_x86.c
@@ -168,8 +168,7 @@ pmc_save_kernel_callchain(uintptr_t *cc, int
nframes, struct trapframe *tf)
*cc++ = pc;
r = fp + sizeof(uintptr_t); /* points to return address */
- if ((td = curthread) == NULL)
- return (1);
+ td = curthread;
if (nframes <= 1)
return (1);
diff --git a/sys/kern/kern_condvar.c b/sys/kern/kern_condvar.c
index 9355819..630075b 100644
--- a/sys/kern/kern_condvar.c
+++ b/sys/kern/kern_condvar.c
@@ -50,7 +50,7 @@ __FBSDID("$FreeBSD$");
* Common sanity checks for cv_wait* functions.
*/
#define CV_ASSERT(cvp, lock, td) do {
\
- KASSERT((td) != NULL, ("%s: curthread NULL", __func__)); \
+ KASSERT((td) != NULL, ("%s: passed td is NULL", __func__)); \
KASSERT(TD_IS_RUNNING(td), ("%s: not TDS_RUNNING", __func__)); \
KASSERT((cvp) != NULL, ("%s: cvp NULL", __func__)); \
KASSERT((lock) != NULL, ("%s: lock NULL", __func__)); \
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 9827a9f..2ab7a09 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -200,7 +200,6 @@ _mtx_lock_flags(struct mtx *m, int opts, const
char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(!TD_IS_IDLETHREAD(curthread),
("mtx_lock() by idle thread %p on sleep mutex %s @ %s:%d",
curthread, m->lock_object.lo_name, file, line));
@@ -225,7 +224,6 @@ _mtx_unlock_flags(struct mtx *m, int opts, const
char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(m->mtx_lock != MTX_DESTROYED,
("mtx_unlock() of destroyed mutex @ %s:%d", file, line));
KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_sleep,
@@ -248,7 +246,6 @@ _mtx_lock_spin_flags(struct mtx *m, int opts,
const char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(m->mtx_lock != MTX_DESTROYED,
("mtx_lock_spin() of destroyed mutex @ %s:%d", file, line));
KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
@@ -272,7 +269,6 @@ _mtx_unlock_spin_flags(struct mtx *m, int opts,
const char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(m->mtx_lock != MTX_DESTROYED,
("mtx_unlock_spin() of destroyed mutex @ %s:%d", file, line));
KASSERT(LOCK_CLASS(&m->lock_object) == &lock_class_mtx_spin,
@@ -303,7 +299,6 @@ mtx_trylock_flags_(struct mtx *m, int opts, const
char *file, int line)
if (SCHEDULER_STOPPED())
return (1);
- MPASS(curthread != NULL);
KASSERT(!TD_IS_IDLETHREAD(curthread),
("mtx_trylock() by idle thread %p on sleep mutex %s @ %s:%d",
curthread, m->lock_object.lo_name, file, line));
diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c
index e0be154..3a51874 100644
--- a/sys/kern/kern_rwlock.c
+++ b/sys/kern/kern_rwlock.c
@@ -241,7 +241,6 @@ _rw_wlock(struct rwlock *rw, const char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(!TD_IS_IDLETHREAD(curthread),
("rw_wlock() by idle thread %p on rwlock %s @ %s:%d",
curthread, rw->lock_object.lo_name, file, line));
@@ -292,7 +291,6 @@ _rw_wunlock(struct rwlock *rw, const char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(rw->rw_lock != RW_DESTROYED,
("rw_wunlock() of destroyed rwlock @ %s:%d", file, line));
_rw_assert(rw, RA_WLOCKED, file, line);
diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c
index 487a324..af2391f 100644
--- a/sys/kern/kern_sx.c
+++ b/sys/kern/kern_sx.c
@@ -249,7 +249,6 @@ _sx_slock(struct sx *sx, int opts, const char
*file, int line)
if (SCHEDULER_STOPPED())
return (0);
- MPASS(curthread != NULL);
KASSERT(!TD_IS_IDLETHREAD(curthread),
("sx_slock() by idle thread %p on sx %s @ %s:%d",
curthread, sx->lock_object.lo_name, file, line));
@@ -303,7 +302,6 @@ _sx_xlock(struct sx *sx, int opts, const char
*file, int line)
if (SCHEDULER_STOPPED())
return (0);
- MPASS(curthread != NULL);
KASSERT(!TD_IS_IDLETHREAD(curthread),
("sx_xlock() by idle thread %p on sx %s @ %s:%d",
curthread, sx->lock_object.lo_name, file, line));
@@ -330,7 +328,6 @@ sx_try_xlock_(struct sx *sx, const char *file, int line)
if (SCHEDULER_STOPPED())
return (1);
- MPASS(curthread != NULL);
KASSERT(!TD_IS_IDLETHREAD(curthread),
("sx_try_xlock() by idle thread %p on sx %s @ %s:%d",
curthread, sx->lock_object.lo_name, file, line));
@@ -361,7 +358,6 @@ _sx_sunlock(struct sx *sx, const char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
("sx_sunlock() of destroyed sx @ %s:%d", file, line));
_sx_assert(sx, SA_SLOCKED, file, line);
@@ -378,7 +374,6 @@ _sx_xunlock(struct sx *sx, const char *file, int line)
if (SCHEDULER_STOPPED())
return;
- MPASS(curthread != NULL);
KASSERT(sx->sx_lock != SX_LOCK_DESTROYED,
("sx_xunlock() of destroyed sx @ %s:%d", file, line));
_sx_assert(sx, SA_XLOCKED, file, line);
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index c4ad7b8..7c21644 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -622,7 +622,6 @@ thread_single(int mode)
p = td->td_proc;
mtx_assert(&Giant, MA_NOTOWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
- KASSERT((td != NULL), ("curthread is NULL"));
if ((p->p_flag & P_HADTHREADS) == 0)
return (0);
diff --git a/sys/kern/vfs_subr.c b/sys/kern/vfs_subr.c
index 06d16c0..5c781c2 100644
--- a/sys/kern/vfs_subr.c
+++ b/sys/kern/vfs_subr.c
@@ -3416,7 +3416,6 @@ vfs_unmountall(void)
struct thread *td;
int error;
- KASSERT(curthread != NULL, ("vfs_unmountall: NULL curthread"));
CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
td = curthread;
--
1.7.7.4
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