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Back out revision 1.34 until we can come up with a more accurate patch.

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This commit is contained in:
Chris Costello 2003-02-17 22:31:27 +00:00
parent 2f2fead1a7
commit be20391041
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share/man/man9/mutex.9
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@ -477,66 +477,7 @@ access memory in userspace, such as
.Xr fuword 9 ,
etc.
No locks are needed when calling these functions.
.Ss Giant Lock Manipulation Macros
The following macros are useful when dealing with the Giant
lock:
.Bl -tag -width GIANT_REQUIRED
.It Dv GIANT_REQUIRED
Macro used for a routine that wants to assert the Giant lock.
.It Dv PICKUP_GIANT
Allows a routine to hold the Giant lock and save it's
.Xr witness 4
lock order.
.It Dv DROP_GIANT
Allows a routine to drop the Giant lock and restore it's
.Xr witness 4
lock order.
.El
.Pp
It should be noted that
.Dv PICKUP_GIANT
and
.Dv DROP_GIANT
have to be paired together and cannot operate on seperate levels,
i.e. the following is incorrect and not possible:
.Bd -literal
void incorrect()
{
initialization;
PICKUP_GIANT;
if (condition) {
/* stuff ... */
DROP_GIANT;
}
}
.Ed
.Pp
A correct way of calling
.Dv PICKUP_GIANT
and
.Dv DROP_GIANT :
.Bd -literal
void correct()
{
initialization;
PICKUP_GIANT;
if (condition) {
/* stuff ... */
/* more stuff ... */
}
DROP_GIANT;
}
.Ed
.Sh SEE ALSO
.Xr ddb 4 ,
.Xr witness 4 ,
.Xr condvar 9 ,
.Xr msleep 9 ,
.Xr mtx_pool 9 ,
@ -548,9 +489,3 @@ functions appeared in
.Bsx 4.1
and
.Fx 5.0 .
.Sh AUTHORS
This manual page is partially derived from its
.Bsx
counterpart with parts written by Jason Evans and improvements from
Chuck Paterson, Doug Rabson, Matthew Dillon, Greg Lehey, Jake Burkholder
and Sheldon Hearn.