Instead of asserting that a mutex is not still locked after unlocking it,
assert that the mutex is owned and not recursed prior to unlocking it.

This should give a clearer diagnostic when a programm

Instead of asserting that a mutex is not still locked after unlocking it,
assert that the mutex is owned and not recursed prior to unlocking it.

This should give a clearer diagnostic when a programming error is caught.

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Assert that when using an interlock mutex it is not recursed when lockmgr()
is called.

Ok'd by: jhb

convert if/panic -> KASSERT, explain what triggered the assertion

Fix a precedence bug. ! has higher precedence than &.

Proc locking.

Change and clean the mutex lock interface.

mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

simil

Change and clean the mutex lock interface.

mtx_enter(lock, type) becomes:

mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)

similarily, for releasing a lock, we now have:

mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.

The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.

Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:

MTX_QUIET and MTX_NOSWITCH

The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:

mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.

Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.

Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.

Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.

Finally, caught up to the interface changes in all sys code.

Contributors: jake, jhb, jasone (in no particular order)

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Convert all simplelocks to mutexes and remove the simplelock implementations.

Remove MUTEX_DECLARE() and MTX_COLD. Instead, postpone full mutex
initialization until after malloc() is safe to call, then iterate through
all mutexes and complete their initialization.

This chang

Remove MUTEX_DECLARE() and MTX_COLD. Instead, postpone full mutex
initialization until after malloc() is safe to call, then iterate through
all mutexes and complete their initialization.

This change is necessary in order to avoid some circular bootstrapping
dependencies.

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Use msleep instead of mtx_exit; tsleep; mtx_enter, which is not safe.

- machine/mutex.h -> sys/mutex.h
- The initial lock_mtx mutex used in the lockmgr code is initialized very
early, so use MUTEX_DECLARE() and MTX_COLD.

For lockmgr mutex protection, use an array of mutexes that are allocated
and initialized during boot. This avoids bloating sizeof(struct lock).
As a side effect, it is no longer necessary to enforce

For lockmgr mutex protection, use an array of mutexes that are allocated
and initialized during boot. This avoids bloating sizeof(struct lock).
As a side effect, it is no longer necessary to enforce the assumtion that
lockinit()/lockdestroy() calls are paired, so the LK_VALID flag has been
removed.

Idea taken from: BSD/OS.

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Convert lockmgr locks from using simple locks to using mutexes.

Add lockdestroy() and appropriate invocations, which corresponds to
lockinit() and must be called to clean up after a lockmgr lock is

Convert lockmgr locks from using simple locks to using mutexes.

Add lockdestroy() and appropriate invocations, which corresponds to
lockinit() and must be called to clean up after a lockmgr lock is no
longer needed.

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Move MAXCPU from machine/smp.h to machine/param.h to fix breakage
with !SMP kernels. Also, replace NCPUS with MAXCPU since they are
redundant.

Make LINT compile.

Eliminate the undocumented, experimental, non-delivering and highly
dangerous MAX_PERF option.

Lock reporting and assertion changes.
* lockstatus() and VOP_ISLOCKED() gets a new process argument and a new
return value: LK_EXCLOTHER, when the lock is held exclusively by another
process.
* T

Lock reporting and assertion changes.
* lockstatus() and VOP_ISLOCKED() gets a new process argument and a new
return value: LK_EXCLOTHER, when the lock is held exclusively by another
process.
* The ASSERT_VOP_(UN)LOCKED family is extended to use what this gives them
* Extend the vnode_if.src format to allow more exact specification than
locked/unlocked.

This commit should not do any semantic changes unless you are using
DEBUG_VFS_LOCKS.

Discussed with: grog, mch, peter, phk
Reviewed by: peter

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Correct a locking error in apause: It should always hold
the simple lock when it returns.

Also, eliminate spinning on a uniprocessor. It's pointless.

Submitted by: bde,
Assar Westerlund <assar@s

Correct a locking error in apause: It should always hold
the simple lock when it returns.

Also, eliminate spinning on a uniprocessor. It's pointless.

Submitted by: bde,
Assar Westerlund <assar@sics.se>

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Fix process p_locks accounting. Conversions of the owner to LK_KERNPROC
caused p_locks to be improperly accounted.

Submitted by: Tor.Egge@fast.no

$Id$ -> $FreeBSD$

When requesting an exclusive lock with LK_NOWAIT, do not panic
if LK_RECURSIVE is not set, as we will simply return that the
lock is busy and not actually deadlock. This allows processes
to use polli

When requesting an exclusive lock with LK_NOWAIT, do not panic
if LK_RECURSIVE is not set, as we will simply return that the
lock is busy and not actually deadlock. This allows processes
to use polling locks against buffers that they may already
hold exclusively locked.

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Convert buffer locking from using the B_BUSY and B_WANTED flags to using
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK

Convert buffer locking from using the B_BUSY and B_WANTED flags to using
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.

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fix breakage for alphas.
Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>

This solves a deadlock that can occur when read()ing into a file-mmap()
space. When doing this, it is possible to for another process to attempt
to get an exclusive lock on the vnode and deadlock the

This solves a deadlock that can occur when read()ing into a file-mmap()
space. When doing this, it is possible to for another process to attempt
to get an exclusive lock on the vnode and deadlock the mmap/read
combination when the uiomove() call tries to obtain a second
shared lock on the vnode. There is still a potential deadlock
situation with write()/mmap().
Submitted by: Matt Dillon <dillon@freebsd.org>
Reviewed by: Luoqi Chen <luoqi@freebsd.org>
Delimmitted by tag PRE_MATT_MMAP_LOCK and POST_MATT_MMAP_LOCK
in kern/kern_lock.c kern/kern_subr.c

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Add 'options DEBUG_LOCKS', which stores extra information in struct
lock, and add some macros and function parameters to make sure that
the information get to the point where it can be put in the loc

Add 'options DEBUG_LOCKS', which stores extra information in struct
lock, and add some macros and function parameters to make sure that
the information get to the point where it can be put in the lock
structure.

While I'm here, add DEBUG_VFS_LOCKS to LINT.

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KNFize, by bde.