Author: kib
Date: Fri Dec 3 16:15:44 2010
New Revision: 216150
URL: http://svn.freebsd.org/changeset/base/216150
Log:
Reviewed by: jeff, rwatson
MFC after: 1 week
Modified:
head/sys/kern/uipc_usrreq.c
Modified: head/sys/kern/uipc_usrreq.c
==============================================================================
--- head/sys/kern/uipc_usrreq.c Fri Dec 3 16:07:50 2010 (r216149)
+++ head/sys/kern/uipc_usrreq.c Fri Dec 3 16:15:44 2010 (r216150)
@@ -76,6 +76,7 @@ __FBSDID("$FreeBSD$");
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/protosw.h>
+#include <sys/queue.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/socket.h>
@@ -115,6 +116,13 @@ static struct unp_head unp_shead; /* (l)
static struct unp_head unp_dhead; /* (l) List of datagram sockets. */
static struct unp_head unp_sphead; /* (l) List of seqpacket sockets. */
+struct unp_defer {
+ SLIST_ENTRY(unp_defer) ud_link;
+ struct file *ud_fp;
+};
+static SLIST_HEAD(, unp_defer) unp_defers;
+static int unp_defers_count;
+
static const struct sockaddr sun_noname = { sizeof(sun_noname), AF_LOCAL };
/*
@@ -126,6 +134,13 @@ static const struct sockaddr sun_noname
static struct task unp_gc_task;
/*
+ * The close of unix domain sockets attached as SCM_RIGHTS is
+ * postponed to the taskqueue, to avoid arbitrary recursion depth.
+ * The attached sockets might have another sockets attached.
+ */
+static struct task unp_defer_task;
+
+/*
* Both send and receive buffers are allocated PIPSIZ bytes of buffering for
* stream sockets, although the total for sender and receiver is actually
* only PIPSIZ.
@@ -164,6 +179,9 @@ SYSCTL_ULONG(_net_local_seqpacket, OID_A
&unpsp_recvspace, 0, "Default seqpacket receive space.");
SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0,
"File descriptors in flight.");
+SYSCTL_INT(_net_local, OID_AUTO, deferred, CTLFLAG_RD,
+ &unp_defers_count, 0,
+ "File descriptors deferred to taskqueue for close.");
/*
* Locking and synchronization:
@@ -213,6 +231,7 @@ SYSCTL_INT(_net_local, OID_AUTO, infligh
*/
static struct rwlock unp_link_rwlock;
static struct mtx unp_list_lock;
+static struct mtx unp_defers_lock;
#define UNP_LINK_LOCK_INIT() rw_init(&unp_link_rwlock,
\
"unp_link_rwlock")
@@ -234,6 +253,11 @@ static struct mtx unp_list_lock;
#define UNP_LIST_LOCK() mtx_lock(&unp_list_lock)
#define UNP_LIST_UNLOCK() mtx_unlock(&unp_list_lock)
+#define UNP_DEFERRED_LOCK_INIT() mtx_init(&unp_defers_lock, \
+ "unp_defer", NULL, MTX_DEF)
+#define UNP_DEFERRED_LOCK() mtx_lock(&unp_defers_lock)
+#define UNP_DEFERRED_UNLOCK() mtx_unlock(&unp_defers_lock)
+
#define UNP_PCB_LOCK_INIT(unp) mtx_init(&(unp)->unp_mtx, \
"unp_mtx", "unp_mtx", \
MTX_DUPOK|MTX_DEF|MTX_RECURSE)
@@ -259,8 +283,9 @@ static void unp_init(void);
static int unp_internalize(struct mbuf **, struct thread *);
static void unp_internalize_fp(struct file *);
static int unp_externalize(struct mbuf *, struct mbuf **);
-static void unp_externalize_fp(struct file *);
+static int unp_externalize_fp(struct file *);
static struct mbuf *unp_addsockcred(struct thread *, struct mbuf *);
+static void unp_process_defers(void * __unused, int);
/*
* Definitions of protocols supported in the LOCAL domain.
@@ -1764,9 +1789,12 @@ unp_init(void)
LIST_INIT(&unp_dhead);
LIST_INIT(&unp_shead);
LIST_INIT(&unp_sphead);
+ SLIST_INIT(&unp_defers);
TASK_INIT(&unp_gc_task, 0, unp_gc, NULL);
+ TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL);
UNP_LINK_LOCK_INIT();
UNP_LIST_LOCK_INIT();
+ UNP_DEFERRED_LOCK_INIT();
}
static int
@@ -1970,9 +1998,45 @@ fptounp(struct file *fp)
static void
unp_discard(struct file *fp)
{
+ struct unp_defer *dr;
+
+ if (unp_externalize_fp(fp)) {
+ dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK);
+ dr->ud_fp = fp;
+ UNP_DEFERRED_LOCK();
+ SLIST_INSERT_HEAD(&unp_defers, dr, ud_link);
+ UNP_DEFERRED_UNLOCK();
+ atomic_add_int(&unp_defers_count, 1);
+ taskqueue_enqueue(taskqueue_thread, &unp_defer_task);
+ } else
+ (void) closef(fp, (struct thread *)NULL);
+}
+
+static void
+unp_process_defers(void *arg __unused, int pending)
+{
+ struct unp_defer *dr;
+ SLIST_HEAD(, unp_defer) drl;
+ int count;
- unp_externalize_fp(fp);
- (void) closef(fp, (struct thread *)NULL);
+ SLIST_INIT(&drl);
+ for (;;) {
+ UNP_DEFERRED_LOCK();
+ if (SLIST_FIRST(&unp_defers) == NULL) {
+ UNP_DEFERRED_UNLOCK();
+ break;
+ }
+ SLIST_SWAP(&unp_defers, &drl, unp_defer);
+ UNP_DEFERRED_UNLOCK();
+ count = 0;
+ while ((dr = SLIST_FIRST(&drl)) != NULL) {
+ SLIST_REMOVE_HEAD(&drl, ud_link);
+ closef(dr->ud_fp, NULL);
+ free(dr, M_TEMP);
+ count++;
+ }
+ atomic_add_int(&unp_defers_count, -count);
+ }
}
static void
@@ -1990,16 +2054,21 @@ unp_internalize_fp(struct file *fp)
UNP_LINK_WUNLOCK();
}
-static void
+static int
unp_externalize_fp(struct file *fp)
{
struct unpcb *unp;
+ int ret;
UNP_LINK_WLOCK();
- if ((unp = fptounp(fp)) != NULL)
+ if ((unp = fptounp(fp)) != NULL) {
unp->unp_msgcount--;
+ ret = 1;
+ } else
+ ret = 0;
unp_rights--;
UNP_LINK_WUNLOCK();
+ return (ret);
}
/*
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