[PATCH] IPMI: per-channel command registration

This patch adds the ability to register for a command per-channel in the
IPMI driver.

If your BMC supports multiple channels, incoming messages can be useful to
have the ability to register to receive commands on a specific channel
instead the current behaviour of all channels.

Signed-off-by: David Barksdale <amatus@ocgnet.org>
Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/IPMI.txt

@@ -326,9 +326,12 @@ for events, they will all receive all events that come in.
 
 For receiving commands, you have to individually register commands you
 want to receive.  Call ipmi_register_for_cmd() and supply the netfn
-and command name for each command you want to receive.  Only one user
-may be registered for each netfn/cmd, but different users may register
-for different commands.
+and command name for each command you want to receive.  You also
+specify a bitmask of the channels you want to receive the command from
+(or use IPMI_CHAN_ALL for all channels if you don't care).  Only one
+user may be registered for each netfn/cmd/channel, but different users
+may register for different commands, or the same command if the
+channel bitmasks do not overlap.
 
 From userland, equivalent IOCTLs are provided to do these functions.
 

drivers/char/ipmi/ipmi_devintf.c

@@ -377,7 +377,8 @@ static int ipmi_ioctl(struct inode  *inode,
 			break;
 		}
 
-		rv = ipmi_register_for_cmd(priv->user, val.netfn, val.cmd);
+		rv = ipmi_register_for_cmd(priv->user, val.netfn, val.cmd,
+					   IPMI_CHAN_ALL);
 		break;
 	}
 
@@ -390,7 +391,36 @@ static int ipmi_ioctl(struct inode  *inode,
 			break;
 		}
 
-		rv = ipmi_unregister_for_cmd(priv->user, val.netfn, val.cmd);
+		rv = ipmi_unregister_for_cmd(priv->user, val.netfn, val.cmd,
+					     IPMI_CHAN_ALL);
+		break;
+	}
+
+	case IPMICTL_REGISTER_FOR_CMD_CHANS:
+	{
+		struct ipmi_cmdspec_chans val;
+
+		if (copy_from_user(&val, arg, sizeof(val))) {
+			rv = -EFAULT;
+			break;
+		}
+
+		rv = ipmi_register_for_cmd(priv->user, val.netfn, val.cmd,
+					   val.chans);
+		break;
+	}
+
+	case IPMICTL_UNREGISTER_FOR_CMD_CHANS:
+	{
+		struct ipmi_cmdspec_chans val;
+
+		if (copy_from_user(&val, arg, sizeof(val))) {
+			rv = -EFAULT;
+			break;
+		}
+
+		rv = ipmi_unregister_for_cmd(priv->user, val.netfn, val.cmd,
+					     val.chans);
 		break;
 	}
 

drivers/char/ipmi/ipmi_msghandler.c

@@ -96,6 +96,7 @@ struct cmd_rcvr
 	ipmi_user_t   user;
 	unsigned char netfn;
 	unsigned char cmd;
+	unsigned int  chans;
 
 	/*
 	 * This is used to form a linked lised during mass deletion.
@@ -953,24 +954,41 @@ int ipmi_set_gets_events(ipmi_user_t user, int val)
 
 static struct cmd_rcvr *find_cmd_rcvr(ipmi_smi_t    intf,
 				      unsigned char netfn,
-				      unsigned char cmd)
+				      unsigned char cmd,
+				      unsigned char chan)
 {
 	struct cmd_rcvr *rcvr;
 
 	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
-		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd))
+		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)
+					&& (rcvr->chans & (1 << chan)))
 			return rcvr;
 	}
 	return NULL;
 }
 
+static int is_cmd_rcvr_exclusive(ipmi_smi_t    intf,
+				 unsigned char netfn,
+				 unsigned char cmd,
+				 unsigned int  chans)
+{
+	struct cmd_rcvr *rcvr;
+
+	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
+		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)
+					&& (rcvr->chans & chans))
+			return 0;
+	}
+	return 1;
+}
+
 int ipmi_register_for_cmd(ipmi_user_t   user,
 			  unsigned char netfn,
-			  unsigned char cmd)
+			  unsigned char cmd,
+			  unsigned int  chans)
 {
 	ipmi_smi_t      intf = user->intf;
 	struct cmd_rcvr *rcvr;
-	struct cmd_rcvr *entry;
 	int             rv = 0;
 
 
@@ -979,12 +997,12 @@ int ipmi_register_for_cmd(ipmi_user_t   user,
 		return -ENOMEM;
 	rcvr->cmd = cmd;
 	rcvr->netfn = netfn;
+	rcvr->chans = chans;
 	rcvr->user = user;
 
 	mutex_lock(&intf->cmd_rcvrs_mutex);
 	/* Make sure the command/netfn is not already registered. */
-	entry = find_cmd_rcvr(intf, netfn, cmd);
-	if (entry) {
+	if (!is_cmd_rcvr_exclusive(intf, netfn, cmd, chans)) {
 		rv = -EBUSY;
 		goto out_unlock;
 	}
@@ -1001,24 +1019,39 @@ int ipmi_register_for_cmd(ipmi_user_t   user,
 
 int ipmi_unregister_for_cmd(ipmi_user_t   user,
 			    unsigned char netfn,
-			    unsigned char cmd)
+			    unsigned char cmd,
+			    unsigned int  chans)
 {
 	ipmi_smi_t      intf = user->intf;
 	struct cmd_rcvr *rcvr;
+	struct cmd_rcvr *rcvrs = NULL;
+	int i, rv = -ENOENT;
 
 	mutex_lock(&intf->cmd_rcvrs_mutex);
-	/* Make sure the command/netfn is not already registered. */
-	rcvr = find_cmd_rcvr(intf, netfn, cmd);
-	if ((rcvr) && (rcvr->user == user)) {
-		list_del_rcu(&rcvr->link);
-		mutex_unlock(&intf->cmd_rcvrs_mutex);
-		synchronize_rcu();
-		kfree(rcvr);
-		return 0;
-	} else {
-		mutex_unlock(&intf->cmd_rcvrs_mutex);
-		return -ENOENT;
+	for (i = 0; i < IPMI_NUM_CHANNELS; i++) {
+		if (((1 << i) & chans) == 0)
+			continue;
+		rcvr = find_cmd_rcvr(intf, netfn, cmd, i);
+		if (rcvr == NULL)
+			continue;
+		if (rcvr->user == user) {
+			rv = 0;
+			rcvr->chans &= ~chans;
+			if (rcvr->chans == 0) {
+				list_del_rcu(&rcvr->link);
+				rcvr->next = rcvrs;
+				rcvrs = rcvr;
+			}
+		}
 	}
+	mutex_unlock(&intf->cmd_rcvrs_mutex);
+	synchronize_rcu();
+	while (rcvrs) {
+		rcvr = rcvrs;
+		rcvrs = rcvr->next;
+		kfree(rcvr);
+	}
+	return rv;
 }
 
 void ipmi_user_set_run_to_completion(ipmi_user_t user, int val)
@@ -2548,6 +2581,7 @@ static int handle_ipmb_get_msg_cmd(ipmi_smi_t          intf,
 	int                      rv = 0;
 	unsigned char            netfn;
 	unsigned char            cmd;
+	unsigned char            chan;
 	ipmi_user_t              user = NULL;
 	struct ipmi_ipmb_addr    *ipmb_addr;
 	struct ipmi_recv_msg     *recv_msg;
@@ -2568,9 +2602,10 @@ static int handle_ipmb_get_msg_cmd(ipmi_smi_t          intf,
 
 	netfn = msg->rsp[4] >> 2;
 	cmd = msg->rsp[8];
+	chan = msg->rsp[3] & 0xf;
 
 	rcu_read_lock();
-	rcvr = find_cmd_rcvr(intf, netfn, cmd);
+	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
 	if (rcvr) {
 		user = rcvr->user;
 		kref_get(&user->refcount);
@@ -2728,6 +2763,7 @@ static int handle_lan_get_msg_cmd(ipmi_smi_t          intf,
 	int                      rv = 0;
 	unsigned char            netfn;
 	unsigned char            cmd;
+	unsigned char            chan;
 	ipmi_user_t              user = NULL;
 	struct ipmi_lan_addr     *lan_addr;
 	struct ipmi_recv_msg     *recv_msg;
@@ -2748,9 +2784,10 @@ static int handle_lan_get_msg_cmd(ipmi_smi_t          intf,
 
 	netfn = msg->rsp[6] >> 2;
 	cmd = msg->rsp[10];
+	chan = msg->rsp[3] & 0xf;
 
 	rcu_read_lock();
-	rcvr = find_cmd_rcvr(intf, netfn, cmd);
+	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
 	if (rcvr) {
 		user = rcvr->user;
 		kref_get(&user->refcount);

include/linux/ipmi.h

@@ -148,6 +148,13 @@ struct ipmi_lan_addr
 #define IPMI_BMC_CHANNEL  0xf
 #define IPMI_NUM_CHANNELS 0x10
 
+/*
+ * Used to signify an "all channel" bitmask.  This is more than the
+ * actual number of channels because this is used in userland and
+ * will cover us if the number of channels is extended.
+ */
+#define IPMI_CHAN_ALL     (~0)
+
 
 /*
  * A raw IPMI message without any addressing.  This covers both
@@ -350,18 +357,21 @@ int ipmi_request_supply_msgs(ipmi_user_t          user,
 
 /*
  * When commands come in to the SMS, the user can register to receive
- * them.  Only one user can be listening on a specific netfn/cmd pair
+ * them.  Only one user can be listening on a specific netfn/cmd/chan tuple
  * at a time, you will get an EBUSY error if the command is already
  * registered.  If a command is received that does not have a user
  * registered, the driver will automatically return the proper
- * error.
+ * error.  Channels are specified as a bitfield, use IPMI_CHAN_ALL to
+ * mean all channels.
  */
 int ipmi_register_for_cmd(ipmi_user_t   user,
 			  unsigned char netfn,
-			  unsigned char cmd);
+			  unsigned char cmd,
+			  unsigned int  chans);
 int ipmi_unregister_for_cmd(ipmi_user_t   user,
 			    unsigned char netfn,
-			    unsigned char cmd);
+			    unsigned char cmd,
+			    unsigned int  chans);
 
 /*
  * Allow run-to-completion mode to be set for the interface of
@@ -571,6 +581,36 @@ struct ipmi_cmdspec
 #define IPMICTL_UNREGISTER_FOR_CMD	_IOR(IPMI_IOC_MAGIC, 15,	\
 					     struct ipmi_cmdspec)
 
+/*
+ * Register to get commands from other entities on specific channels.
+ * This way, you can only listen on specific channels, or have messages
+ * from some channels go to one place and other channels to someplace
+ * else.  The chans field is a bitmask, (1 << channel) for each channel.
+ * It may be IPMI_CHAN_ALL for all channels.
+ */
+struct ipmi_cmdspec_chans
+{
+	unsigned int netfn;
+	unsigned int cmd;
+	unsigned int chans;
+};
+
+/*
+ * Register to receive a specific command on specific channels.  error values:
+ *   - EFAULT - an address supplied was invalid.
+ *   - EBUSY - One of the netfn/cmd/chans supplied was already in use.
+ *   - ENOMEM - could not allocate memory for the entry.
+ */
+#define IPMICTL_REGISTER_FOR_CMD_CHANS	_IOR(IPMI_IOC_MAGIC, 28,	\
+					     struct ipmi_cmdspec_chans)
+/*
+ * Unregister some netfn/cmd/chans.  error values:
+ *  - EFAULT - an address supplied was invalid.
+ *  - ENOENT - None of the netfn/cmd/chans were found registered for this user.
+ */
+#define IPMICTL_UNREGISTER_FOR_CMD_CHANS _IOR(IPMI_IOC_MAGIC, 29,	\
+					     struct ipmi_cmdspec_chans)
+
 /* 
  * Set whether this interface receives events.  Note that the first
  * user registered for events will get all pending events for the