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Introduce a mutex into struct sockbuf, sb_mtx, which will be used to

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protect fields in the socket buffer.  Add accessor macros to use the
mutex (SOCKBUF_*()).  Initialize the mutex in soalloc(), and destroy
it in sodealloc().  Add addition, add SOCK_*() access macros which
will protect most remaining fields in the socket; for the time being,
use the receive socket buffer mutex to implement socket level locking
to reduce memory overhead.

Submitted by:	sam
Sponosored by:	FreeBSD Foundation
Obtained from:	BSD/OS
This commit is contained in:
Robert Watson 2004-06-12 16:08:41 +00:00
parent 2653139fd2
commit f6c0cce6d9
2 changed files with 31 additions and 0 deletions
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4
sys/kern/uipc_socket.c
View File

@ -144,6 +144,8 @@ soalloc(int mflags)
return so;
}
#endif
SOCKBUF_LOCK_INIT(&so->so_snd, "so_snd");
SOCKBUF_LOCK_INIT(&so->so_rcv, "so_rcv");
/* XXX race condition for reentrant kernel */
so->so_gencnt = ++so_gencnt;
/* sx_init(&so->so_sxlock, "socket sxlock"); */
@ -245,6 +247,8 @@ sodealloc(struct socket *so)
mac_destroy_socket(so);
#endif
crfree(so->so_cred);
SOCKBUF_LOCK_DESTROY(&so->so_snd);
SOCKBUF_LOCK_DESTROY(&so->so_rcv);
/* sx_destroy(&so->so_sxlock); */
uma_zfree(socket_zone, so);
--numopensockets;

27
sys/sys/socketvar.h
View File

@ -35,6 +35,8 @@
#include <sys/queue.h> /* for TAILQ macros */
#include <sys/selinfo.h> /* for struct selinfo */
#include <sys/_lock.h>
#include <sys/_mutex.h>
/*
* Kernel structure per socket.
@ -93,6 +95,7 @@ struct socket {
*/
struct sockbuf {
struct selinfo sb_sel; /* process selecting read/write */
struct mtx sb_mtx; /* sockbuf lock */
#define sb_startzero sb_mb
struct mbuf *sb_mb; /* the mbuf chain */
struct mbuf *sb_mbtail; /* the last mbuf in the chain */
@ -150,6 +153,30 @@ extern struct mtx accept_mtx;
#define ACCEPT_LOCK() mtx_lock(&accept_mtx)
#define ACCEPT_UNLOCK() mtx_unlock(&accept_mtx)
/*
* Per-socket buffer mutex used to protect most fields in the socket
* buffer.
*/
#define SOCKBUF_MTX(_sb) (&(_sb)->sb_mtx)
#define SOCKBUF_LOCK_INIT(_sb, _name) \
mtx_init(SOCKBUF_MTX(_sb), _name, NULL, MTX_DEF)
#define SOCKBUF_LOCK_DESTROY(_sb) mtx_destroy(SOCKBUF_MTX(_sb))
#define SOCKBUF_LOCK(_sb) mtx_lock(SOCKBUF_MTX(_sb))
#define SOCKBUF_OWNED(_sb) mtx_owned(SOCKBUF_MTX(_sb))
#define SOCKBUF_UNLOCK(_sb) mtx_unlock(SOCKBUF_MTX(_sb))
#define SOCKBUF_LOCK_ASSERT(_sb) mtx_assert(SOCKBUF_MTX(_sb), MA_OWNED)
/*
* Per-socket mutex: we reuse the receive socket buffer mutex for space
* efficiency. This decision should probably be revisited as we optimize
* locking for the socket code.
*/
#define SOCK_MTX(_so) SOCKBUF_MTX(&(_so)->so_rcv)
#define SOCK_LOCK(_so) SOCKBUF_LOCK(&(_so)->so_rcv)
#define SOCK_OWNED(_so) SOCKBUF_OWNED(&(_so)->so_rcv)
#define SOCK_UNLOCK(_so) SOCKBUF_UNLOCK(&(_so)->so_rcv)
#define SOCK_LOCK_ASSERT(_so) SOCKBUF_LOCK_ASSERT(&(_so)->so_rcv)
/*
* Socket state bits.
*/