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Add a new per-thread private flag: TDP_GEOM.

Browse Source 
This flag gets set whenever the thread posts an event on the GEOM
event queue, and if the flag is set when the thread is prepared
to return to userland from the kernel, g_waitidle() will be called
to make sure that the posted events have completed.

This can replace an insufficient number of g_waitidle() calls in
various other places, and has the advantage of being failsafe:  Any
system call which does a VOP_OPEN()/VOP_CLOSE will now correctly
wait for any geom events it posted as part of spoils or tastes.

Assert that topology and Giant is not held in g_waitidle().
This commit is contained in:
Poul-Henning Kamp 2004-10-23 20:49:17 +00:00
parent a11021f362
commit 9197ce2ee5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=136837
3 changed files with 16 additions and 1 deletions
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9
sys/geom/geom_event.c
View File

@ -47,12 +47,14 @@ __FBSDID("$FreeBSD$");
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <machine/stdarg.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <geom/geom.h>
#include <geom/geom_int.h>
#include <machine/stdarg.h>
TAILQ_HEAD(event_tailq_head, g_event);
static struct event_tailq_head g_events = TAILQ_HEAD_INITIALIZER(g_events);
@ -79,8 +81,12 @@ void
g_waitidle(void)
{
g_topology_assert_not();
mtx_assert(&Giant, MA_NOTOWNED);
while (g_pending_events)
tsleep(&g_pending_events, PPAUSE, "g_waitidle", hz/5);
curthread->td_pflags &= ~TDP_GEOM;
}
void
@ -279,6 +285,7 @@ g_post_event_x(g_event_t *func, void *arg, int flag, int wuflag, struct g_event
wakeup(&g_wait_event);
if (epp != NULL)
*epp = ep;
curthread->td_pflags |= TDP_GEOM;
return (0);
}

7
sys/kern/subr_trap.c
View File

@ -94,6 +94,13 @@ userret(td, frame, oticks)
PROC_UNLOCK(p);
#endif
/*
* If this thread tickled GEOM, we need to wait for the giggling to
* stop before we return to userland
*/
if (td->td_pflags & TDP_GEOM)
g_waitidle();
/*
* Let the scheduler adjust our priority etc.
*/

1
sys/sys/proc.h
View File

@ -375,6 +375,7 @@ struct thread {
#define TDP_SCHED2 0x00002000 /* Reserved for scheduler private use */
#define TDP_SCHED3 0x00004000 /* Reserved for scheduler private use */
#define TDP_SCHED4 0x00008000 /* Reserved for scheduler private use */
#define TDP_GEOM 0x00010000 /* Settle GEOM before finishing syscall */
/*
* Reasons that the current thread can not be run yet.