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Bug #908

Updated by tuxillo over 10 years ago

Any suggestions on how to make this clearer are welcome. 

 

 Index: notes/porting_drivers.txt 
 
 =================================================================== 
 
 RCS file: /home/aggelos/imports/vcs/dcvs/doc/notes/porting_drivers.txt,v 
 
 retrieving revision 1.3 
 
 diff -u -p -u -r1.3 porting_drivers.txt 
 
 --- notes/porting_drivers.txt 	 29 Dec 2007 18:35:59 -0000 	 1.3 
 
 +++ notes/porting_drivers.txt 	 6 Jan 2008 17:40:24 -0000 
 
 @@ -84,6 +84,24 @@ $DragonFly: doc/notes/porting_drivers.tx 
    
    call is replaced with 
 	 
 	 lockmgr(&my_lock, LK_EXCLUSIVE|LK_NOWAIT); 

 

 +    On occasion, the FreeBSD code will use mtx_sleep() or msleep() 
 
 +    (currently [01/2008], those macros have identical definitions) 
 
 +    in order to release a mutex and sleep without missing any 
 
 +    wakeups that might occur in between. The DragonFly idiom for 
 
 +    this case is to enter a critical section and use tsleep_interlock() 
 
 +    to let threads in other cpus know that we're about to go to 
 
 +    sleep. In our example, you would substitute 
 
 + 
 
 + 	 crit_enter(); 
 
 + 	 tsleep_interlock(ident); 
 
 + 	 lockmgr(&my_lock, LK_RELEASE); 
 
 + 	 tsleep(ident, flags, "whatever", timeout); 
 
 + 	 crit_exit(); 
 
 + 	 lockmgr(&my_lock, LK_EXCLUSIVE); 
 
 + 
 
 +    for 
 
 + 	 msleep(ident, &my_mtx, flags, "whatever", timeout); 
 
 + 
    
    As for mtx_assert() calls, translate them like this: 

 	 

 	 mtx_assert(&my_mtx, MA_OWNED) -> KKASSERT(lockstatus(&my_lock, curthread) != 0)

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