svn commit: r267165 - head/sys/dev/netmap
Luigi Rizzo
luigi at FreeBSD.org
Fri Jun 6 14:58:26 UTC 2014
Author: luigi
Date: Fri Jun 6 14:58:25 2014
New Revision: 267165
URL: http://svnweb.freebsd.org/changeset/base/267165
Log:
align comments with the ones in our development trunk
Modified:
head/sys/dev/netmap/netmap.c
head/sys/dev/netmap/netmap_kern.h
Modified: head/sys/dev/netmap/netmap.c
==============================================================================
--- head/sys/dev/netmap/netmap.c Fri Jun 6 14:57:40 2014 (r267164)
+++ head/sys/dev/netmap/netmap.c Fri Jun 6 14:58:25 2014 (r267165)
@@ -270,6 +270,7 @@ netmap_disable_ring(struct netmap_kring
}
+/* stop or enable all the rings of na */
static void
netmap_set_all_rings(struct ifnet *ifp, int stopped)
{
@@ -303,6 +304,13 @@ netmap_set_all_rings(struct ifnet *ifp,
}
+/*
+ * Convenience function used in drivers. Waits for current txsync()s/rxsync()s
+ * to finish and prevents any new one from starting. Call this before turning
+ * netmap mode off, or before removing the harware rings (e.g., on module
+ * onload). As a rule of thumb for linux drivers, this should be placed near
+ * each napi_disable().
+ */
void
netmap_disable_all_rings(struct ifnet *ifp)
{
@@ -310,6 +318,11 @@ netmap_disable_all_rings(struct ifnet *i
}
+/*
+ * Convenience function used in drivers. Re-enables rxsync and txsync on the
+ * adapter's rings In linux drivers, this should be placed near each
+ * napi_enable().
+ */
void
netmap_enable_all_rings(struct ifnet *ifp)
{
@@ -393,6 +406,7 @@ nm_dump_buf(char *p, int len, int lim, c
* Fetch configuration from the device, to cope with dynamic
* reconfigurations after loading the module.
*/
+/* call with NMG_LOCK held */
int
netmap_update_config(struct netmap_adapter *na)
{
@@ -447,18 +461,20 @@ netmap_rxsync_compat(struct netmap_kring
return na->nm_rxsync(na, kring->ring_id, flags);
}
+/* kring->nm_sync callback for the host tx ring */
static int
netmap_txsync_to_host_compat(struct netmap_kring *kring, int flags)
{
- (void)flags;
+ (void)flags; /* unused */
netmap_txsync_to_host(kring->na);
return 0;
}
+/* kring->nm_sync callback for the host rx ring */
static int
netmap_rxsync_from_host_compat(struct netmap_kring *kring, int flags)
{
- (void)flags;
+ (void)flags; /* unused */
netmap_rxsync_from_host(kring->na, NULL, NULL);
return 0;
}
@@ -489,6 +505,7 @@ netmap_rxsync_from_host_compat(struct ne
* Note: for compatibility, host krings are created even when not needed.
* The tailroom space is currently used by vale ports for allocating leases.
*/
+/* call with NMG_LOCK held */
int
netmap_krings_create(struct netmap_adapter *na, u_int tailroom)
{
@@ -567,6 +584,7 @@ netmap_krings_create(struct netmap_adapt
/* undo the actions performed by netmap_krings_create */
+/* call with NMG_LOCK held */
void
netmap_krings_delete(struct netmap_adapter *na)
{
@@ -586,6 +604,7 @@ netmap_krings_delete(struct netmap_adapt
* on the rings connected to the host so we need to purge
* them first.
*/
+/* call with NMG_LOCK held */
static void
netmap_hw_krings_delete(struct netmap_adapter *na)
{
@@ -598,6 +617,12 @@ netmap_hw_krings_delete(struct netmap_ad
}
+/* create a new netmap_if for a newly registered fd.
+ * If this is the first registration of the adapter,
+ * also create the netmap rings and their in-kernel view,
+ * the netmap krings.
+ */
+/* call with NMG_LOCK held */
static struct netmap_if*
netmap_if_new(const char *ifname, struct netmap_adapter *na)
{
@@ -608,17 +633,23 @@ netmap_if_new(const char *ifname, struct
return NULL;
}
- if (na->active_fds)
+ if (na->active_fds) /* already registered */
goto final;
+ /* create and init the krings arrays.
+ * Depending on the adapter, this may also create
+ * the netmap rings themselves
+ */
if (na->nm_krings_create(na))
goto cleanup;
+ /* create all missing netmap rings */
if (netmap_mem_rings_create(na))
goto cleanup;
final:
+ /* in all cases, create a new netmap if */
nifp = netmap_mem_if_new(ifname, na);
if (nifp == NULL)
goto cleanup;
@@ -638,8 +669,8 @@ cleanup:
/* grab a reference to the memory allocator, if we don't have one already. The
* reference is taken from the netmap_adapter registered with the priv.
- *
*/
+/* call with NMG_LOCK held */
static int
netmap_get_memory_locked(struct netmap_priv_d* p)
{
@@ -672,6 +703,7 @@ netmap_get_memory_locked(struct netmap_p
}
+/* call with NMG_LOCK *not* held */
int
netmap_get_memory(struct netmap_priv_d* p)
{
@@ -683,6 +715,7 @@ netmap_get_memory(struct netmap_priv_d*
}
+/* call with NMG_LOCK held */
static int
netmap_have_memory_locked(struct netmap_priv_d* p)
{
@@ -690,6 +723,7 @@ netmap_have_memory_locked(struct netmap_
}
+/* call with NMG_LOCK held */
static void
netmap_drop_memory_locked(struct netmap_priv_d* p)
{
@@ -755,6 +789,7 @@ netmap_do_unregif(struct netmap_priv_d *
netmap_mem_if_delete(na, nifp);
}
+/* call with NMG_LOCK held */
static __inline int
nm_tx_si_user(struct netmap_priv_d *priv)
{
@@ -762,6 +797,7 @@ nm_tx_si_user(struct netmap_priv_d *priv
(priv->np_txqlast - priv->np_txqfirst > 1));
}
+/* call with NMG_LOCK held */
static __inline int
nm_rx_si_user(struct netmap_priv_d *priv)
{
@@ -771,8 +807,12 @@ nm_rx_si_user(struct netmap_priv_d *priv
/*
+ * Destructor of the netmap_priv_d, called when the fd has
+ * no active open() and mmap(). Also called in error paths.
+ *
* returns 1 if this is the last instance and we can free priv
*/
+/* call with NMG_LOCK held */
int
netmap_dtor_locked(struct netmap_priv_d *priv)
{
@@ -805,6 +845,7 @@ netmap_dtor_locked(struct netmap_priv_d
}
+/* call with NMG_LOCK *not* held */
void
netmap_dtor(void *data)
{
@@ -1194,6 +1235,12 @@ netmap_get_na(struct nmreq *nmr, struct
if (*na != NULL) /* valid match in netmap_get_bdg_na() */
goto pipes;
+ /*
+ * This must be a hardware na, lookup the name in the system.
+ * Note that by hardware we actually mean "it shows up in ifconfig".
+ * This may still be a tap, a veth/epair, or even a
+ * persistent VALE port.
+ */
ifp = ifunit_ref(nmr->nr_name);
if (ifp == NULL) {
return ENXIO;
@@ -1212,6 +1259,11 @@ netmap_get_na(struct nmreq *nmr, struct
netmap_adapter_get(ret);
pipes:
+ /*
+ * If we are opening a pipe whose parent was not in netmap mode,
+ * we have to allocate the pipe array now.
+ * XXX get rid of this clumsiness (2014-03-15)
+ */
error = netmap_pipe_alloc(*na, nmr);
out:
@@ -1219,7 +1271,7 @@ out:
netmap_adapter_put(ret);
if (ifp)
- if_rele(ifp);
+ if_rele(ifp); /* allow live unloading of drivers modules */
return error;
}
@@ -1555,10 +1607,9 @@ netmap_do_regif(struct netmap_priv_d *pr
goto out;
}
nifp = netmap_if_new(NM_IFPNAME(ifp), na);
+
+ /* Allocate a netmap_if and, if necessary, all the netmap_ring's */
if (nifp == NULL) { /* allocation failed */
- /* we should drop the allocator, but only
- * if we were the ones who grabbed it
- */
error = ENOMEM;
goto out;
}
@@ -1568,10 +1619,8 @@ netmap_do_regif(struct netmap_priv_d *pr
} else {
/* Otherwise set the card in netmap mode
* and make it use the shared buffers.
- *
- * do not core lock because the race is harmless here,
- * there cannot be any traffic to netmap_transmit()
*/
+ /* cache the allocator info in the na */
na->na_lut = na->nm_mem->pools[NETMAP_BUF_POOL].lut;
ND("%p->na_lut == %p", na, na->na_lut);
na->na_lut_objtotal = na->nm_mem->pools[NETMAP_BUF_POOL].objtotal;
@@ -1585,6 +1634,9 @@ out:
*err = error;
if (error) {
priv->np_na = NULL;
+ /* we should drop the allocator, but only
+ * if we were the ones who grabbed it
+ */
if (need_mem)
netmap_drop_memory_locked(priv);
}
@@ -2008,6 +2060,12 @@ flush_tx:
continue;
/* only one thread does txsync */
if (nm_kr_tryget(kring)) {
+ /* either busy or stopped
+ * XXX if the ring is stopped, sleeping would
+ * be better. In current code, however, we only
+ * stop the rings for brief intervals (2014-03-14)
+ */
+
if (netmap_verbose)
RD(2, "%p lost race on txring %d, ok",
priv, i);
@@ -2049,7 +2107,7 @@ flush_tx:
*/
if (want_rx) {
int send_down = 0; /* transparent mode */
- /* two rounds here to for race avoidance */
+ /* two rounds here for race avoidance */
do_retry_rx:
for (i = priv->np_rxqfirst; i < priv->np_rxqlast; i++) {
int found = 0;
@@ -2139,6 +2197,7 @@ do_retry_rx:
static int netmap_hw_krings_create(struct netmap_adapter *);
+/* default notify callback */
static int
netmap_notify(struct netmap_adapter *na, u_int n_ring,
enum txrx tx, int flags)
@@ -2148,11 +2207,16 @@ netmap_notify(struct netmap_adapter *na,
if (tx == NR_TX) {
kring = na->tx_rings + n_ring;
OS_selwakeup(&kring->si, PI_NET);
+ /* optimization: avoid a wake up on the global
+ * queue if nobody has registered for more
+ * than one ring
+ */
if (na->tx_si_users > 0)
OS_selwakeup(&na->tx_si, PI_NET);
} else {
kring = na->rx_rings + n_ring;
OS_selwakeup(&kring->si, PI_NET);
+ /* optimization: same as above */
if (na->rx_si_users > 0)
OS_selwakeup(&na->rx_si, PI_NET);
}
@@ -2160,7 +2224,11 @@ netmap_notify(struct netmap_adapter *na,
}
-// XXX check handling of failures
+/* called by all routines that create netmap_adapters.
+ * Attach na to the ifp (if any) and provide defaults
+ * for optional callbacks. Defaults assume that we
+ * are creating an hardware netmap_adapter.
+ */
int
netmap_attach_common(struct netmap_adapter *na)
{
@@ -2182,6 +2250,10 @@ netmap_attach_common(struct netmap_adapt
NETMAP_SET_CAPABLE(ifp);
if (na->nm_krings_create == NULL) {
+ /* we assume that we have been called by a driver,
+ * since other port types all provide their own
+ * nm_krings_create
+ */
na->nm_krings_create = netmap_hw_krings_create;
na->nm_krings_delete = netmap_hw_krings_delete;
}
@@ -2195,10 +2267,11 @@ netmap_attach_common(struct netmap_adapt
}
+/* standard cleanup, called by all destructors */
void
netmap_detach_common(struct netmap_adapter *na)
{
- if (na->ifp)
+ if (na->ifp != NULL)
WNA(na->ifp) = NULL; /* XXX do we need this? */
if (na->tx_rings) { /* XXX should not happen */
@@ -2255,7 +2328,11 @@ netmap_attach(struct netmap_adapter *arg
hwna->nm_ndo.ndo_start_xmit = linux_netmap_start_xmit;
#endif /* linux */
- D("success for %s", NM_IFPNAME(ifp));
+ D("success for %s tx %d/%d rx %d/%d queues/slots",
+ NM_IFPNAME(ifp),
+ hwna->up.num_tx_rings, hwna->up.num_tx_desc,
+ hwna->up.num_rx_rings, hwna->up.num_rx_desc
+ );
return 0;
fail:
@@ -2295,6 +2372,7 @@ NM_DBG(netmap_adapter_put)(struct netmap
return 1;
}
+/* nm_krings_create callback for all hardware native adapters */
int
netmap_hw_krings_create(struct netmap_adapter *na)
{
@@ -2310,8 +2388,7 @@ netmap_hw_krings_create(struct netmap_ad
/*
- * Free the allocated memory linked to the given ``netmap_adapter``
- * object.
+ * Called on module unload by the netmap-enabled drivers
*/
void
netmap_detach(struct ifnet *ifp)
@@ -2406,6 +2483,10 @@ done:
m_freem(m);
/* unconditionally wake up listeners */
na->nm_notify(na, na->num_rx_rings, NR_RX, 0);
+ /* this is normally netmap_notify(), but for nics
+ * connected to a bridge it is netmap_bwrap_intr_notify(),
+ * that possibly forwards the frames through the switch
+ */
return (error);
}
Modified: head/sys/dev/netmap/netmap_kern.h
==============================================================================
--- head/sys/dev/netmap/netmap_kern.h Fri Jun 6 14:57:40 2014 (r267164)
+++ head/sys/dev/netmap/netmap_kern.h Fri Jun 6 14:58:25 2014 (r267165)
@@ -183,9 +183,6 @@ extern NMG_LOCK_T netmap_global_lock;
* the next empty buffer as known by the hardware (next_to_check or so).
* TX rings: hwcur + hwofs coincides with next_to_send
*
- * Clients cannot issue concurrent syscall on a ring. The system
- * detects this and reports an error using two flags,
- * NKR_WBUSY and NKR_RBUSY
* For received packets, slot->flags is set to nkr_slot_flags
* so we can provide a proper initial value (e.g. set NS_FORWARD
* when operating in 'transparent' mode).
@@ -208,7 +205,7 @@ extern NMG_LOCK_T netmap_global_lock;
* The kring is manipulated by txsync/rxsync and generic netmap function.
*
* Concurrent rxsync or txsync on the same ring are prevented through
- * by nm_kr_lock() which in turn uses nr_busy. This is all we need
+ * by nm_kr_(try)lock() which in turn uses nr_busy. This is all we need
* for NIC rings, and for TX rings attached to the host stack.
*
* RX rings attached to the host stack use an mbq (rx_queue) on both
@@ -440,15 +437,18 @@ struct netmap_adapter {
/*
* nm_dtor() is the cleanup routine called when destroying
* the adapter.
+ * Called with NMG_LOCK held.
*
* nm_register() is called on NIOCREGIF and close() to enter
* or exit netmap mode on the NIC
+ * Called with NMG_LOCK held.
*
* nm_txsync() pushes packets to the underlying hw/switch
*
* nm_rxsync() collects packets from the underlying hw/switch
*
* nm_config() returns configuration information from the OS
+ * Called with NMG_LOCK held.
*
* nm_krings_create() create and init the krings array
* (the array layout must conform to the description
@@ -456,13 +456,12 @@ struct netmap_adapter {
*
* nm_krings_delete() cleanup and delete the kring array
*
- * nm_notify() is used to act after data have become available.
+ * nm_notify() is used to act after data have become available
+ * (or the stopped state of the ring has changed)
* For hw devices this is typically a selwakeup(),
* but for NIC/host ports attached to a switch (or vice-versa)
* we also need to invoke the 'txsync' code downstream.
*/
-
- /* private cleanup */
void (*nm_dtor)(struct netmap_adapter *);
int (*nm_register)(struct netmap_adapter *, int onoff);
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