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The BUF_*() routines must be internally splbio() protected otherwise they

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can cause a biodone() from a disk interrupt to spin when the interrupt
code tries to grab the simplelock.  Masking BIO here means buftimelock
and/or lk->lk_interlock shouldn't be held when an interrupt tries to grab
them.
This commit is contained in:
Peter Wemm 1999-06-27 11:40:03 +00:00
parent e0e25bba1a
commit 79db8f4587
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=48273
2 changed files with 74 additions and 16 deletions
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45
sys/sys/bio.h
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)buf.h 8.9 (Berkeley) 3/30/95
* $Id: buf.h,v 1.71 1999/06/26 14:25:03 peter Exp $
* $Id: buf.h,v 1.72 1999/06/27 09:13:19 peter Exp $
*/
#ifndef _SYS_BUF_H_
@ -251,15 +251,19 @@ extern char *buf_wmesg; /* Default buffer lock message */
*/
static __inline int BUF_LOCK __P((struct buf *, int));
static __inline int
BUF_LOCK (struct buf *bp, int locktype)
BUF_LOCK(struct buf *bp, int locktype)
{
int s, ret;
s = splbio();
simple_lock(&buftimelock);
locktype |= LK_INTERLOCK;
bp->b_lock.lk_wmesg = buf_wmesg;
bp->b_lock.lk_prio = PRIBIO + 4;
bp->b_lock.lk_timo = 0;
return (lockmgr(&(bp)->b_lock, locktype, &buftimelock, curproc));
ret = lockmgr(&(bp)->b_lock, locktype, &buftimelock, curproc);
splx(s);
return ret;
}
/*
* Get a lock sleeping with specified interruptably and timeout.
@ -268,20 +272,33 @@ static __inline int BUF_TIMELOCK __P((struct buf *, int, char *, int, int));
static __inline int
BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo)
{
int s, ret;
s = splbio();
simple_lock(&buftimelock);
locktype |= LK_INTERLOCK;
bp->b_lock.lk_wmesg = wmesg;
bp->b_lock.lk_prio = (PRIBIO + 4) | catch;
bp->b_lock.lk_timo = timo;
return (lockmgr(&(bp)->b_lock, (locktype), &buftimelock, curproc));
ret = lockmgr(&(bp)->b_lock, (locktype), &buftimelock, curproc);
splx(s);
return ret;
}
/*
* Release a lock. Only the acquiring process may free the lock unless
* it has been handed off to biodone.
*/
#define BUF_UNLOCK(bp) \
lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curproc)
static __inline void BUF_UNLOCK __P((struct buf *));
static __inline void
BUF_UNLOCK(struct buf *bp)
{
int s;
s = splbio();
lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curproc);
splx(s);
}
/*
* Free a buffer lock.
*/
@ -299,19 +316,31 @@ static __inline void
BUF_KERNPROC(struct buf *bp)
{
struct buf *nbp;
int s;
s = splbio();
if (bp->b_flags & B_ASYNC)
bp->b_lock.lk_lockholder = LK_KERNPROC;
for (nbp = TAILQ_FIRST(&bp->b_cluster.cluster_head);
nbp; nbp = TAILQ_NEXT(&nbp->b_cluster, cluster_entry))
if (nbp->b_flags & B_ASYNC)
nbp->b_lock.lk_lockholder = LK_KERNPROC;
splx(s);
}
/*
* Find out the number of references to a lock.
*/
#define BUF_REFCNT(bp) \
lockcount(&(bp)->b_lock)
static __inline int BUF_REFCNT __P((struct buf *));
static __inline int
BUF_REFCNT(struct buf *bp)
{
int s, ret;
s = splbio();
ret = lockcount(&(bp)->b_lock);
splx(s);
return ret;
}
#endif /* KERNEL */

45
sys/sys/buf.h
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)buf.h 8.9 (Berkeley) 3/30/95
* $Id: buf.h,v 1.71 1999/06/26 14:25:03 peter Exp $
* $Id: buf.h,v 1.72 1999/06/27 09:13:19 peter Exp $
*/
#ifndef _SYS_BUF_H_
@ -251,15 +251,19 @@ extern char *buf_wmesg; /* Default buffer lock message */
*/
static __inline int BUF_LOCK __P((struct buf *, int));
static __inline int
BUF_LOCK (struct buf *bp, int locktype)
BUF_LOCK(struct buf *bp, int locktype)
{
int s, ret;
s = splbio();
simple_lock(&buftimelock);
locktype |= LK_INTERLOCK;
bp->b_lock.lk_wmesg = buf_wmesg;
bp->b_lock.lk_prio = PRIBIO + 4;
bp->b_lock.lk_timo = 0;
return (lockmgr(&(bp)->b_lock, locktype, &buftimelock, curproc));
ret = lockmgr(&(bp)->b_lock, locktype, &buftimelock, curproc);
splx(s);
return ret;
}
/*
* Get a lock sleeping with specified interruptably and timeout.
@ -268,20 +272,33 @@ static __inline int BUF_TIMELOCK __P((struct buf *, int, char *, int, int));
static __inline int
BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo)
{
int s, ret;
s = splbio();
simple_lock(&buftimelock);
locktype |= LK_INTERLOCK;
bp->b_lock.lk_wmesg = wmesg;
bp->b_lock.lk_prio = (PRIBIO + 4) | catch;
bp->b_lock.lk_timo = timo;
return (lockmgr(&(bp)->b_lock, (locktype), &buftimelock, curproc));
ret = lockmgr(&(bp)->b_lock, (locktype), &buftimelock, curproc);
splx(s);
return ret;
}
/*
* Release a lock. Only the acquiring process may free the lock unless
* it has been handed off to biodone.
*/
#define BUF_UNLOCK(bp) \
lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curproc)
static __inline void BUF_UNLOCK __P((struct buf *));
static __inline void
BUF_UNLOCK(struct buf *bp)
{
int s;
s = splbio();
lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curproc);
splx(s);
}
/*
* Free a buffer lock.
*/
@ -299,19 +316,31 @@ static __inline void
BUF_KERNPROC(struct buf *bp)
{
struct buf *nbp;
int s;
s = splbio();
if (bp->b_flags & B_ASYNC)
bp->b_lock.lk_lockholder = LK_KERNPROC;
for (nbp = TAILQ_FIRST(&bp->b_cluster.cluster_head);
nbp; nbp = TAILQ_NEXT(&nbp->b_cluster, cluster_entry))
if (nbp->b_flags & B_ASYNC)
nbp->b_lock.lk_lockholder = LK_KERNPROC;
splx(s);
}
/*
* Find out the number of references to a lock.
*/
#define BUF_REFCNT(bp) \
lockcount(&(bp)->b_lock)
static __inline int BUF_REFCNT __P((struct buf *));
static __inline int
BUF_REFCNT(struct buf *bp)
{
int s, ret;
s = splbio();
ret = lockcount(&(bp)->b_lock);
splx(s);
return ret;
}
#endif /* KERNEL */