mdoc(7) cleanup.
This commit is contained in:
Ruslan Ermilov
parent
7dd6c38875
commit
51b37a2355
@ -28,7 +28,7 @@
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.\" from BSDI $Id: mutex.4,v 1.1.2.3 1998/04/27 22:53:13 ewv Exp $
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.\" $FreeBSD$
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.\"
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.Dd April 20, 1998
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.Dd February 12, 2001
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.Dt MUTEX 9
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.Os
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.Sh NAME
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@ -127,7 +127,7 @@ Once a spin mutex has been acquired it is not permissible to acquire a
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blocking mutex.
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.Pp
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The storage needed to implement a mutex is provided by a
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.Dv struct mtx .
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.Vt struct mtx .
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In general this should be treated as an opaque object and
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referenced only with the mutex primitives.
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.Pp
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@ -137,25 +137,27 @@ function must be used to initialize a mutex
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before it can be passed to
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.Fn mtx_lock .
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The
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.Ar name
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.Fa name
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argument is used by the witness code
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to classify a mutex when doing checks of lock ordering.
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The pointer passed in as the
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.Ar name
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.Fa name
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is saved rather than the data it points to.
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The data pointed to must remain stable
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until the mutex is destroyed.
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The
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.Ar opts
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argument is used to set the type of mutex. It may contain either
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.Fa opts
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argument is used to set the type of mutex.
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It may contain either
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.Dv MTX_DEF
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or
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.Dv MTX_SPIN
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but not both. Optionally, it may also contain the
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but not both.
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Optionally, it may also contain the
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.Dv MTX_RECURSE
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bit, which signifies that the mutex will be allowed to recurse.
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It is not permissible to pass the same
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.Ar mutex
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.Fa mutex
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to
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.Fn mtx_init
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multiple times without intervening calls to
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@ -199,15 +201,17 @@ functions acquire a
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or
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.Dv MTX_SPIN
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lock, respectively, and also accept a
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.Ar flags
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.Fa flags
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argument.
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In both cases, the only flag presently available for lock acquires is
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.Dv MTX_QUIET .
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If the
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.Dv MTX_QUIET
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bit is turned on in the
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.Ar flags
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argument, then if KTR_LOCK tracing is being done,
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.Fa flags
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argument, then if
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.Dv KTR_LOCK
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tracing is being done,
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it will be silenced during the lock acquire.
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.Pp
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The
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@ -215,7 +219,7 @@ The
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function is used to acquire exclusive access
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to those objects protected by the mutex
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pointed to by
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.Ar mutex .
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.Fa mutex .
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If the mutex can not be immediately acquired
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.Fn mtx_try_enter
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will return 0,
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@ -227,8 +231,9 @@ The
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function has the same behavior as
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.Fn mtx_trylock
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but should be used when the caller desires to pass in a
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.Ar flags
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value. Presently, the only valid value in the
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.Fa flags
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value.
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Presently, the only valid value in the
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.Fn mtx_trylock
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case is
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.Dv MTX_QUIET ,
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@ -260,7 +265,7 @@ and
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.Fn mtx_unlock_spin_flags
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functions behave in exactly the same way as do the standard mutex
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unlock routines above, while also allowing a
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.Ar flags
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.Fa flags
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argument which may only be
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.Dv MTX_QUIET
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in the
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@ -271,7 +276,8 @@ and
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.Dv MTX_NOSWITCH
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in the
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.Fn mtx_unlock_flags
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case. The behavior of
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case.
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The behavior of
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.Dv MTX_QUIET
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is identical to its behavior in the mutex lock routines.
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The
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@ -286,7 +292,7 @@ the release of the mutex.
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The
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.Fn mtx_destroy
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function is used to destroy
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.Ar mutex
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.Fa mutex
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so the data associated with it may be freed
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or otherwise overwritten.
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Any mutex which is destroyed
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@ -302,23 +308,23 @@ The
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.Fn mtx_owned
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function returns non-zero
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if the current process holds
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.Ar mutex .
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.Fa mutex .
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If the current process does not hold
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.Ar mutex
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.Fa mutex
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zero is returned.
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.Pp
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The
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.Fn mtx_recursed
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function returns non-zero if the
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.Ar mutex
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.Fa mutex
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is recursed.
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This check should only be made if the running thread already owns
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.Ar mutex .
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.Fa mutex .
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.Pp
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The
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.Fn mtx_assert
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function allows assertions to be made about
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.Ar mutex .
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function allows assertions to be made about
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.Fa mutex .
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If the assertions are not true and the kernel is compiled with
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.Dv INVARIANTS
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then the kernel will panic.
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@ -374,7 +380,7 @@ their primary purpose is to protect portions of the code
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that implement default (i.e. sleep) locks.
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.Ss Initialization Options
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The options passed in the
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.Ar opts
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.Fa opts
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argument of
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.Fn mtx_init
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specify the mutex type.
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@ -413,13 +419,15 @@ and
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.Fn mtx_unlock_spin_flags
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functions provide some basic options to the caller,
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and are often used only under special circumstances to modify lock or
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unlock behavior. Standard locking and unlocking should be performed with the
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unlock behavior.
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Standard locking and unlocking should be performed with the
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.Fn mtx_lock ,
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.Fn mtx_lock_spin ,
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.Fn mtx_unlock ,
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and
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.Fn mtx_unlock_spin
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functions. If one of these flags is required then, and only then,
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functions.
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If one of these flags is required then, and only then,
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should the corresponding flags-accepting routines be used.
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.Pp
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Options that modify mutex behavior:
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