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Split the FILEDESC_LOCK in two variants.

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FILEDESC_LOCK_FAST will just grab the interlocking mutex and hold
it.  This should be used for simple modifications of a field.

FILEDESC_LOCK holds a (homegrown) sleepable lock which should be used
where sleeping is required.

The homegrown lock will probably be replaced with a generic type of lock
once we have found out how that should look.

Help and reviews by:	rwatson
This commit is contained in:
Poul-Henning Kamp 2004-11-17 07:39:58 +00:00
parent 003e18aef4
commit d533c6e9a5
1 changed files with 57 additions and 8 deletions
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65
sys/sys/filedesc.h
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@ -35,6 +35,7 @@
#include <sys/queue.h>
#include <sys/event.h>
#include <sys/priority.h>
#include <sys/_lock.h>
#include <sys/_mutex.h>
@ -60,12 +61,13 @@ struct filedesc {
u_short fd_refcnt; /* reference count */
struct mtx fd_mtx; /* protects members of this struct */
int fd_locked; /* long lock flag */
int fd_wanted; /* "" */
struct kqlist fd_kqlist; /* list of kqueues on this filedesc */
int fd_holdleaderscount; /* block fdfree() for shared close() */
int fd_holdleaderswakeup; /* fdfree() needs wakeup */
};
/*
* Structure to keep track of (process leader, struct fildedesc) tuples.
* Each process has a pointer to such a structure when detailed tracking
@ -93,14 +95,61 @@ struct filedesc_to_leader {
#ifdef _KERNEL
/* Lock a file descriptor table. */
#define FILEDESC_LOCK(fd) mtx_lock(&(fd)->fd_mtx)
#define FILEDESC_UNLOCK(fd) mtx_unlock(&(fd)->fd_mtx)
#define FILEDESC_LOCKED(fd) mtx_owned(&(fd)->fd_mtx)
#define FILEDESC_LOCK_ASSERT(fd, type) mtx_assert(&(fd)->fd_mtx, (type))
#define FILEDESC_LOCK_DESC "filedesc structure"
#define FILEDESC_LOCK(fd) \
do { \
mtx_lock(&(fd)->fd_mtx); \
(fd)->fd_wanted++; \
while ((fd)->fd_locked) \
msleep(&(fd)->fd_locked, &(fd)->fd_mtx, PLOCK, "fdesc", 0); \
(fd)->fd_locked = 2; \
(fd)->fd_wanted--; \
mtx_unlock(&(fd)->fd_mtx); \
} while (0);
#define FILEDESC_LOCK_FAST(fd) FILEDESC_LOCK(fd);
#define FILEDESC_UNLOCK_FAST(fd) FILEDESC_UNLOCK(fd);
#define FILEDESC_UNLOCK(fd) \
do { \
mtx_lock(&(fd)->fd_mtx); \
KASSERT((fd)->fd_locked == 2, \
("fdesc locking mistake %d should be %d", (fd)->fd_locked, 2)); \
(fd)->fd_locked = 0; \
if ((fd)->fd_wanted) \
wakeup(&(fd)->fd_locked); \
mtx_unlock(&(fd)->fd_mtx); \
} while (0);
#define FILEDESC_LOCK_FAST(fd) \
do { \
mtx_lock(&(fd)->fd_mtx); \
(fd)->fd_wanted++; \
while ((fd)->fd_locked) \
msleep(&(fd)->fd_locked, &(fd)->fd_mtx, PLOCK, "fdesc", 0); \
(fd)->fd_locked = 1; \
(fd)->fd_wanted--; \
} while (0);
#define FILEDESC_UNLOCK_FAST(fd) \
do { \
KASSERT((fd)->fd_locked == 1, \
("fdesc locking mistake %d should be %d", (fd)->fd_locked, 1)); \
(fd)->fd_locked = 0; \
if ((fd)->fd_wanted) \
wakeup(&(fd)->fd_locked); \
mtx_unlock(&(fd)->fd_mtx); \
} while (0);
#ifdef INVARIANT_SUPPORT
#define FILEDESC_LOCK_ASSERT(fd, arg) \
do { \
if ((arg) == MA_OWNED) \
KASSERT((fd)->fd_locked != 0, ("fdesc locking mistake")); \
else \
KASSERT((fd)->fd_locked == 0, ("fdesc locking mistake")); \
} while (0);
#else
#define FILEDESC_LOCK_ASSERT(fd, arg)
#endif
#define FILEDESC_LOCK_DESC "filedesc structure"
struct thread;