[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>

4 files changed, 138 insertions, 28 deletions

diff --git a/Documentation/IPMI.txt b/Documentation/IPMI.txt
index 0256805b548f..7756e09ea759 100644
--- a/Documentation/IPMI.txt
+++ b/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.
 
diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index 68d7c61a864e..81fcf0ce21d1 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/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;
         }
 
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 843d34c8627c..2455e8d478ac 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/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();
+        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 0;
-        } else {
-                mutex_unlock(&intf->cmd_rcvrs_mutex);
-                return -ENOENT;
         }
+        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);
diff --git a/include/linux/ipmi.h b/include/linux/ipmi.h
index d09fbeabf1dc..796ca009fd46 100644
--- a/include/linux/ipmi.h
+++ b/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