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Index: sys/dev/netmap/netmap.c
===================================================================
--- sys/dev/netmap/netmap.c
+++ sys/dev/netmap/netmap.c
@@ -830,6 +830,7 @@
struct netmap_kring *kring;
u_int n[NR_TXRX];
enum txrx t;
+ int err = 0;
if (na->tx_rings != NULL) {
if (netmap_debug & NM_DEBUG_ON)
@@ -869,7 +870,6 @@
for (i = 0; i < n[t]; i++) {
kring = NMR(na, t)[i];
bzero(kring, sizeof(*kring));
- kring->na = na;
kring->notify_na = na;
kring->ring_id = i;
kring->tx = t;
@@ -895,13 +895,21 @@
nm_txrx2str(t), i);
ND("ktx %s h %d c %d t %d",
kring->name, kring->rhead, kring->rcur, kring->rtail);
+ err = nm_os_selinfo_init(&kring->si, kring->name);
+ if (err) {
+ netmap_krings_delete(na);
+ return err;
+ }
mtx_init(&kring->q_lock, (t == NR_TX ? "nm_txq_lock" : "nm_rxq_lock"), NULL, MTX_DEF);
- nm_os_selinfo_init(&kring->si);
+ kring->na = na; /* setting this field marks the mutex as initialized */
}
- nm_os_selinfo_init(&na->si[t]);
+ err = nm_os_selinfo_init(&na->si[t], na->name);
+ if (err) {
+ netmap_krings_delete(na);
+ return err;
+ }
}
-
return 0;
}
@@ -925,7 +933,8 @@
/* we rely on the krings layout described above */
for ( ; kring != na->tailroom; kring++) {
- mtx_destroy(&(*kring)->q_lock);
+ if ((*kring)->na != NULL)
+ mtx_destroy(&(*kring)->q_lock);
nm_os_selinfo_uninit(&(*kring)->si);
}
nm_os_free(na->tx_rings);
Index: sys/dev/netmap/netmap_freebsd.c
===================================================================
--- sys/dev/netmap/netmap_freebsd.c
+++ sys/dev/netmap/netmap_freebsd.c
@@ -58,6 +58,7 @@
#include <sys/unistd.h> /* RFNOWAIT */
#include <sys/sched.h> /* sched_bind() */
#include <sys/smp.h> /* mp_maxid */
+#include <sys/taskqueue.h> /* taskqueue_enqueue(), taskqueue_create(), ... */
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_types.h> /* IFT_ETHER */
@@ -75,16 +76,48 @@
/* ======================== FREEBSD-SPECIFIC ROUTINES ================== */
-void nm_os_selinfo_init(NM_SELINFO_T *si) {
- struct mtx *m = &si->m;
- mtx_init(m, "nm_kn_lock", NULL, MTX_DEF);
- knlist_init_mtx(&si->si.si_note, m);
+static void
+nm_kqueue_notify(void *opaque, int pending)
+{
+ struct nm_selinfo *si = opaque;
+
+ /* We use a non-zero hint to distinguish this notification call
+ * from the call done in kqueue_scan(), which uses hint=0.
+ */
+ KNOTE_UNLOCKED(&si->si.si_note, /*hint=*/0x100);
}
+int nm_os_selinfo_init(NM_SELINFO_T *si, const char *name) {
+ int err;
+
+ TASK_INIT(&si->ntfytask, 0, nm_kqueue_notify, si);
+ si->ntfytq = taskqueue_create(name, M_NOWAIT,
+ taskqueue_thread_enqueue, &si->ntfytq);
+ if (si->ntfytq == NULL)
+ return -ENOMEM;
+ err = taskqueue_start_threads(&si->ntfytq, 1, PI_NET, "tq %s", name);
+ if (err) {
+ taskqueue_free(si->ntfytq);
+ si->ntfytq = NULL;
+ return err;
+ }
+
+ snprintf(si->mtxname, sizeof(si->mtxname), "nmkl%s", name);
+ mtx_init(&si->m, si->mtxname, NULL, MTX_DEF);
+ knlist_init_mtx(&si->si.si_note, &si->m);
+
+ return (0);
+}
+
void
nm_os_selinfo_uninit(NM_SELINFO_T *si)
{
- /* XXX kqueue(9) needed; these will mirror knlist_init. */
+ if (si->ntfytq == NULL) {
+ return; /* si was not initialized */
+ }
+ taskqueue_drain(si->ntfytq, &si->ntfytask);
+ taskqueue_free(si->ntfytq);
+ si->ntfytq = NULL;
knlist_delete(&si->si.si_note, curthread, /*islocked=*/0);
knlist_destroy(&si->si.si_note);
/* now we don't need the mutex anymore */
@@ -1292,13 +1325,18 @@
/*
* In addition to calling selwakeuppri(), nm_os_selwakeup() also
- * needs to call KNOTE to wake up kqueue listeners.
- * We use a non-zero 'hint' argument to inform the netmap_knrw()
- * function that it is being called from 'nm_os_selwakeup'; this
- * is necessary because when netmap_knrw() is called by the kevent
- * subsystem (i.e. kevent_scan()) we also need to call netmap_poll().
- * The knote uses a private mutex associated to the 'si' (see struct
- * selinfo, struct nm_selinfo, and nm_os_selinfo_init).
+ * needs to call knote() to wake up kqueue listeners.
+ * This operation is deferred to a taskqueue in order to avoid possible
+ * lock order reversals; these may happen because knote() grabs a
+ * private lock associated to the 'si' (see struct selinfo,
+ * struct nm_selinfo, and nm_os_selinfo_init), and nm_os_selwakeup()
+ * can be called while holding the lock associated to a different
+ * 'si'.
+ * When calling knote() we use a non-zero 'hint' argument to inform
+ * the netmap_knrw() function that it is being called from
+ * 'nm_os_selwakeup'; this is necessary because when netmap_knrw() is
+ * called by the kevent subsystem (i.e. kevent_scan()) we also need to
+ * call netmap_poll().
*
* The netmap_kqfilter() function registers one or another f_event
* depending on read or write mode. A pointer to the struct
@@ -1315,11 +1353,7 @@
if (netmap_verbose)
nm_prinf("on knote %p", &si->si.si_note);
selwakeuppri(&si->si, PI_NET);
- /* We use a non-zero hint to distinguish this notification call
- * from the call done in kqueue_scan(), which uses hint=0.
- */
- KNOTE(&si->si.si_note, /*hint=*/0x100,
- mtx_owned(&si->m) ? KNF_LISTLOCKED : 0);
+ taskqueue_enqueue(si->ntfytq, &si->ntfytask);
}
void
Index: sys/dev/netmap/netmap_kern.h
===================================================================
--- sys/dev/netmap/netmap_kern.h
+++ sys/dev/netmap/netmap_kern.h
@@ -133,7 +133,10 @@
struct nm_selinfo {
struct selinfo si;
+ struct taskqueue *ntfytq;
+ struct task ntfytask;
struct mtx m;
+ char mtxname[32];
};
@@ -295,7 +298,7 @@
struct nm_bdg_args;
/* os-specific NM_SELINFO_T initialzation/destruction functions */
-void nm_os_selinfo_init(NM_SELINFO_T *);
+int nm_os_selinfo_init(NM_SELINFO_T *, const char *name);
void nm_os_selinfo_uninit(NM_SELINFO_T *);
const char *nm_dump_buf(char *p, int len, int lim, char *dst);

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