2 files changed, 576 insertions, 9 deletions

diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c
index ae7ed9a22662..b37e133de805 100644
--- a/drivers/scsi/scsi_netlink.c
+++ b/drivers/scsi/scsi_netlink.c
@@ -21,6 +21,7 @@
 #include <linux/time.h>
 #include <linux/jiffies.h>
 #include <linux/security.h>
+#include <linux/delay.h>
 #include <net/sock.h>
 #include <net/netlink.h>
 
@@ -30,6 +31,39 @@
 struct sock *scsi_nl_sock = NULL;
 EXPORT_SYMBOL_GPL(scsi_nl_sock);
 
+static DEFINE_SPINLOCK(scsi_nl_lock);
+static struct list_head scsi_nl_drivers;
+
+static u32      scsi_nl_state;
+#define STATE_EHANDLER_BSY              0x00000001
+
+struct scsi_nl_transport {
+        int (*msg_handler)(struct sk_buff *);
+        void (*event_handler)(struct notifier_block *, unsigned long, void *);
+        unsigned int refcnt;
+        int flags;
+};
+
+/* flags values (bit flags) */
+#define HANDLER_DELETING                0x1
+
+static struct scsi_nl_transport transports[SCSI_NL_MAX_TRANSPORTS] =
+        { {NULL, }, };
+
+
+struct scsi_nl_drvr {
+        struct list_head next;
+        int (*dmsg_handler)(struct Scsi_Host *shost, void *payload,
+                                 u32 len, u32 pid);
+        void (*devt_handler)(struct notifier_block *nb,
+                                 unsigned long event, void *notify_ptr);
+        struct scsi_host_template *hostt;
+        u64 vendor_id;
+        unsigned int refcnt;
+        int flags;
+};
+
+
 
 /**
  * scsi_nl_rcv_msg - Receive message handler.
@@ -45,8 +79,9 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 {
         struct nlmsghdr *nlh;
         struct scsi_nl_hdr *hdr;
-        uint32_t rlen;
-        int err;
+        unsigned long flags;
+        u32 rlen;
+        int err, tport;
 
         while (skb->len >= NLMSG_SPACE(0)) {
                 err = 0;
@@ -65,7 +100,7 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 
                 if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
                         err = -EBADMSG;
-                        return;
+                        goto next_msg;
                 }
 
                 hdr = NLMSG_DATA(nlh);
@@ -83,12 +118,27 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
                 if (nlh->nlmsg_len < (sizeof(*nlh) + hdr->msglen)) {
                         printk(KERN_WARNING "%s: discarding partial message\n",
                                  __func__);
-                        return;
+                        goto next_msg;
                 }
 
                 /*
-                 * We currently don't support anyone sending us a message
+                 * Deliver message to the appropriate transport
                  */
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+
+                tport = hdr->transport;
+                if ((tport < SCSI_NL_MAX_TRANSPORTS) &&
+                    !(transports[tport].flags & HANDLER_DELETING) &&
+                    (transports[tport].msg_handler)) {
+                        transports[tport].refcnt++;
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        err = transports[tport].msg_handler(skb);
+                        spin_lock_irqsave(&scsi_nl_lock, flags);
+                        transports[tport].refcnt--;
+                } else
+                        err = -ENOENT;
+
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
 
 next_msg:
                 if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
@@ -110,14 +160,42 @@ static int
 scsi_nl_rcv_event(struct notifier_block *this, unsigned long event, void *ptr)
 {
         struct netlink_notify *n = ptr;
+        struct scsi_nl_drvr *driver;
+        unsigned long flags;
+        int tport;
 
         if (n->protocol != NETLINK_SCSITRANSPORT)
                 return NOTIFY_DONE;
 
+        spin_lock_irqsave(&scsi_nl_lock, flags);
+        scsi_nl_state |= STATE_EHANDLER_BSY;
+
         /*
-         * Currently, we are not tracking PID's, etc. There is nothing
-         * to handle.
+         * Pass event on to any transports that may be listening
          */
+        for (tport = 0; tport < SCSI_NL_MAX_TRANSPORTS; tport++) {
+                if (!(transports[tport].flags & HANDLER_DELETING) &&
+                    (transports[tport].event_handler)) {
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        transports[tport].event_handler(this, event, ptr);
+                        spin_lock_irqsave(&scsi_nl_lock, flags);
+                }
+        }
+
+        /*
+         * Pass event on to any drivers that may be listening
+         */
+        list_for_each_entry(driver, &scsi_nl_drivers, next) {
+                if (!(driver->flags & HANDLER_DELETING) &&
+                    (driver->devt_handler)) {
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        driver->devt_handler(this, event, ptr);
+                        spin_lock_irqsave(&scsi_nl_lock, flags);
+                }
+        }
+
+        scsi_nl_state &= ~STATE_EHANDLER_BSY;
+        spin_unlock_irqrestore(&scsi_nl_lock, flags);
 
         return NOTIFY_DONE;
 }
@@ -128,7 +206,281 @@ static struct notifier_block scsi_netlink_notifier = {
 
 
 /**
- * scsi_netlink_init - Called by SCSI subsystem to intialize the SCSI transport netlink interface
+ * GENERIC SCSI transport receive and event handlers
+ **/
+
+/**
+ * scsi_generic_msg_handler - receive message handler for GENERIC transport
+ *                       messages
+ *
+ * @skb:                socket receive buffer
+ *
+ **/
+static int
+scsi_generic_msg_handler(struct sk_buff *skb)
+{
+        struct nlmsghdr *nlh = nlmsg_hdr(skb);
+        struct scsi_nl_hdr *snlh = NLMSG_DATA(nlh);
+        struct scsi_nl_drvr *driver;
+        struct Scsi_Host *shost;
+        unsigned long flags;
+        int err = 0, match, pid;
+
+        pid = NETLINK_CREDS(skb)->pid;
+
+        switch (snlh->msgtype) {
+        case SCSI_NL_SHOST_VENDOR:
+                {
+                struct scsi_nl_host_vendor_msg *msg = NLMSG_DATA(nlh);
+
+                /* Locate the driver that corresponds to the message */
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+                match = 0;
+                list_for_each_entry(driver, &scsi_nl_drivers, next) {
+                        if (driver->vendor_id == msg->vendor_id) {
+                                match = 1;
+                                break;
+                        }
+                }
+
+                if ((!match) || (!driver->dmsg_handler)) {
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        err = -ESRCH;
+                        goto rcv_exit;
+                }
+
+                if (driver->flags & HANDLER_DELETING) {
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        err = -ESHUTDOWN;
+                        goto rcv_exit;
+                }
+
+                driver->refcnt++;
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+
+                /* if successful, scsi_host_lookup takes a shost reference */
+                shost = scsi_host_lookup(msg->host_no);
+                if (!shost) {
+                        err = -ENODEV;
+                        goto driver_exit;
+                }
+
+                /* is this host owned by the vendor ? */
+                if (shost->hostt != driver->hostt) {
+                        err = -EINVAL;
+                        goto vendormsg_put;
+                }
+
+                /* pass message on to the driver */
+                err = driver->dmsg_handler(shost, (void *)&msg[1],
+                                         msg->vmsg_datalen, pid);
+
+vendormsg_put:
+                /* release reference by scsi_host_lookup */
+                scsi_host_put(shost);
+
+driver_exit:
+                /* release our own reference on the registration object */
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+                driver->refcnt--;
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                break;
+                }
+
+        default:
+                err = -EBADR;
+                break;
+        }
+
+rcv_exit:
+        if (err)
+                printk(KERN_WARNING "%s: Msgtype %d failed - err %d\n",
+                         __func__, snlh->msgtype, err);
+        return err;
+}
+
+
+/**
+ * scsi_nl_add_transport -
+ *    Registers message and event handlers for a transport. Enables
+ *    receipt of netlink messages and events to a transport.
+ *
+ * @tport:              transport registering handlers
+ * @msg_handler:        receive message handler callback
+ * @event_handler:      receive event handler callback
+ **/
+int
+scsi_nl_add_transport(u8 tport,
+        int (*msg_handler)(struct sk_buff *),
+        void (*event_handler)(struct notifier_block *, unsigned long, void *))
+{
+        unsigned long flags;
+        int err = 0;
+
+        if (tport >= SCSI_NL_MAX_TRANSPORTS)
+                return -EINVAL;
+
+        spin_lock_irqsave(&scsi_nl_lock, flags);
+
+        if (scsi_nl_state & STATE_EHANDLER_BSY) {
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                msleep(1);
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+        }
+
+        if (transports[tport].msg_handler || transports[tport].event_handler) {
+                err = -EALREADY;
+                goto register_out;
+        }
+
+        transports[tport].msg_handler = msg_handler;
+        transports[tport].event_handler = event_handler;
+        transports[tport].flags = 0;
+        transports[tport].refcnt = 0;
+
+register_out:
+        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_add_transport);
+
+
+/**
+ * scsi_nl_remove_transport -
+ *    Disable transport receiption of messages and events
+ *
+ * @tport:              transport deregistering handlers
+ *
+ **/
+void
+scsi_nl_remove_transport(u8 tport)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&scsi_nl_lock, flags);
+        if (scsi_nl_state & STATE_EHANDLER_BSY) {
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                msleep(1);
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+        }
+
+        if (tport < SCSI_NL_MAX_TRANSPORTS) {
+                transports[tport].flags |= HANDLER_DELETING;
+
+                while (transports[tport].refcnt != 0) {
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        schedule_timeout_uninterruptible(HZ/4);
+                        spin_lock_irqsave(&scsi_nl_lock, flags);
+                }
+                transports[tport].msg_handler = NULL;
+                transports[tport].event_handler = NULL;
+                transports[tport].flags = 0;
+        }
+
+        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+        return;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_remove_transport);
+
+
+/**
+ * scsi_nl_add_driver -
+ *    A driver is registering its interfaces for SCSI netlink messages
+ *
+ * @vendor_id:          A unique identification value for the driver.
+ * @hostt:              address of the driver's host template. Used
+ *                      to verify an shost is bound to the driver
+ * @nlmsg_handler:      receive message handler callback
+ * @nlevt_handler:      receive event handler callback
+ *
+ * Returns:
+ *   0 on Success
+ *   error result otherwise
+ **/
+int
+scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
+        int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
+                                 u32 len, u32 pid),
+        void (*nlevt_handler)(struct notifier_block *nb,
+                                 unsigned long event, void *notify_ptr))
+{
+        struct scsi_nl_drvr *driver;
+        unsigned long flags;
+
+        driver = kzalloc(sizeof(*driver), GFP_KERNEL);
+        if (unlikely(!driver)) {
+                printk(KERN_ERR "%s: allocation failure\n", __func__);
+                return -ENOMEM;
+        }
+
+        driver->dmsg_handler = nlmsg_handler;
+        driver->devt_handler = nlevt_handler;
+        driver->hostt = hostt;
+        driver->vendor_id = vendor_id;
+
+        spin_lock_irqsave(&scsi_nl_lock, flags);
+        if (scsi_nl_state & STATE_EHANDLER_BSY) {
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                msleep(1);
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+        }
+        list_add_tail(&driver->next, &scsi_nl_drivers);
+        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_add_driver);
+
+
+/**
+ * scsi_nl_remove_driver -
+ *    An driver is unregistering with the SCSI netlink messages
+ *
+ * @vendor_id:          The unique identification value for the driver.
+ **/
+void
+scsi_nl_remove_driver(u64 vendor_id)
+{
+        struct scsi_nl_drvr *driver;
+        unsigned long flags;
+
+        spin_lock_irqsave(&scsi_nl_lock, flags);
+        if (scsi_nl_state & STATE_EHANDLER_BSY) {
+                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                msleep(1);
+                spin_lock_irqsave(&scsi_nl_lock, flags);
+        }
+
+        list_for_each_entry(driver, &scsi_nl_drivers, next) {
+                if (driver->vendor_id == vendor_id) {
+                        driver->flags |= HANDLER_DELETING;
+                        while (driver->refcnt != 0) {
+                                spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                                schedule_timeout_uninterruptible(HZ/4);
+                                spin_lock_irqsave(&scsi_nl_lock, flags);
+                        }
+                        list_del(&driver->next);
+                        kfree(driver);
+                        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+                        return;
+                }
+        }
+
+        spin_unlock_irqrestore(&scsi_nl_lock, flags);
+
+        printk(KERN_ERR "%s: removal of driver failed - vendor_id 0x%llx\n",
+               __func__, (unsigned long long)vendor_id);
+        return;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_remove_driver);
+
+
+/**
+ * scsi_netlink_init - Called by SCSI subsystem to intialize
+ *      the SCSI transport netlink interface
  *
  **/
 void
@@ -136,6 +488,8 @@ scsi_netlink_init(void)
 {
         int error;
 
+        INIT_LIST_HEAD(&scsi_nl_drivers);
+
         error = netlink_register_notifier(&scsi_netlink_notifier);
         if (error) {
                 printk(KERN_ERR "%s: register of event handler failed - %d\n",
@@ -150,8 +504,15 @@ scsi_netlink_init(void)
                 printk(KERN_ERR "%s: register of recieve handler failed\n",
                                 __func__);
                 netlink_unregister_notifier(&scsi_netlink_notifier);
+                return;
         }
 
+        /* Register the entry points for the generic SCSI transport */
+        error = scsi_nl_add_transport(SCSI_NL_TRANSPORT,
+                                scsi_generic_msg_handler, NULL);
+        if (error)
+                printk(KERN_ERR "%s: register of GENERIC transport handler"
+                                "  failed - %d\n", __func__, error);
         return;
 }
 
@@ -163,6 +524,8 @@ scsi_netlink_init(void)
 void
 scsi_netlink_exit(void)
 {
+        scsi_nl_remove_transport(SCSI_NL_TRANSPORT);
+
         if (scsi_nl_sock) {
                 netlink_kernel_release(scsi_nl_sock);
                 netlink_unregister_notifier(&scsi_netlink_notifier);
@@ -172,3 +535,147 @@ scsi_netlink_exit(void)
 }
 
 
+/*
+ * Exported Interfaces
+ */
+
+/**
+ * scsi_nl_send_transport_msg -
+ *    Generic function to send a single message from a SCSI transport to
+ *    a single process
+ *
+ * @pid:                receiving pid
+ * @hdr:                message payload
+ *
+ **/
+void
+scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr)
+{
+        struct sk_buff *skb;
+        struct nlmsghdr *nlh;
+        const char *fn;
+        char *datab;
+        u32 len, skblen;
+        int err;
+
+        if (!scsi_nl_sock) {
+                err = -ENOENT;
+                fn = "netlink socket";
+                goto msg_fail;
+        }
+
+        len = NLMSG_SPACE(hdr->msglen);
+        skblen = NLMSG_SPACE(len);
+
+        skb = alloc_skb(skblen, GFP_KERNEL);
+        if (!skb) {
+                err = -ENOBUFS;
+                fn = "alloc_skb";
+                goto msg_fail;
+        }
+
+        nlh = nlmsg_put(skb, pid, 0, SCSI_TRANSPORT_MSG, len - sizeof(*nlh), 0);
+        if (!nlh) {
+                err = -ENOBUFS;
+                fn = "nlmsg_put";
+                goto msg_fail_skb;
+        }
+        datab = NLMSG_DATA(nlh);
+        memcpy(datab, hdr, hdr->msglen);
+
+        err = nlmsg_unicast(scsi_nl_sock, skb, pid);
+        if (err < 0) {
+                fn = "nlmsg_unicast";
+                /* nlmsg_unicast already kfree_skb'd */
+                goto msg_fail;
+        }
+
+        return;
+
+msg_fail_skb:
+        kfree_skb(skb);
+msg_fail:
+        printk(KERN_WARNING
+                "%s: Dropped Message : pid %d Transport %d, msgtype x%x, "
+                "msglen %d: %s : err %d\n",
+                __func__, pid, hdr->transport, hdr->msgtype, hdr->msglen,
+                fn, err);
+        return;
+}
+EXPORT_SYMBOL_GPL(scsi_nl_send_transport_msg);
+
+
+/**
+ * scsi_nl_send_vendor_msg - called to send a shost vendor unique message
+ *                      to a specific process id.
+ *
+ * @pid:                process id of the receiver
+ * @host_no:            host # sending the message
+ * @vendor_id:          unique identifier for the driver's vendor
+ * @data_len:           amount, in bytes, of vendor unique payload data
+ * @data_buf:           pointer to vendor unique data buffer
+ *
+ * Returns:
+ *   0 on succesful return
+ *   otherwise, failing error code
+ *
+ * Notes:
+ *      This routine assumes no locks are held on entry.
+ */
+int
+scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
+                         char *data_buf, u32 data_len)
+{
+        struct sk_buff *skb;
+        struct nlmsghdr *nlh;
+        struct scsi_nl_host_vendor_msg *msg;
+        u32 len, skblen;
+        int err;
+
+        if (!scsi_nl_sock) {
+                err = -ENOENT;
+                goto send_vendor_fail;
+        }
+
+        len = SCSI_NL_MSGALIGN(sizeof(*msg) + data_len);
+        skblen = NLMSG_SPACE(len);
+
+        skb = alloc_skb(skblen, GFP_KERNEL);
+        if (!skb) {
+                err = -ENOBUFS;
+                goto send_vendor_fail;
+        }
+
+        nlh = nlmsg_put(skb, 0, 0, SCSI_TRANSPORT_MSG,
+                                skblen - sizeof(*nlh), 0);
+        if (!nlh) {
+                err = -ENOBUFS;
+                goto send_vendor_fail_skb;
+        }
+        msg = NLMSG_DATA(nlh);
+
+        INIT_SCSI_NL_HDR(&msg->snlh, SCSI_NL_TRANSPORT,
+                                SCSI_NL_SHOST_VENDOR, len);
+        msg->vendor_id = vendor_id;
+        msg->host_no = host_no;
+        msg->vmsg_datalen = data_len;   /* bytes */
+        memcpy(&msg[1], data_buf, data_len);
+
+        err = nlmsg_unicast(scsi_nl_sock, skb, pid);
+        if (err)
+                /* nlmsg_multicast already kfree_skb'd */
+                goto send_vendor_fail;
+
+        return 0;
+
+send_vendor_fail_skb:
+        kfree_skb(skb);
+send_vendor_fail:
+        printk(KERN_WARNING
+                "%s: Dropped SCSI Msg : host %d vendor_unique - err %d\n",
+                __func__, host_no, err);
+        return err;
+}
+EXPORT_SYMBOL(scsi_nl_send_vendor_msg);
+
+
diff --git a/include/scsi/scsi_netlink.h b/include/scsi/scsi_netlink.h
index 8c1470cc8209..536752c40d41 100644
--- a/include/scsi/scsi_netlink.h
+++ b/include/scsi/scsi_netlink.h
@@ -22,6 +22,9 @@
 #ifndef SCSI_NETLINK_H
 #define SCSI_NETLINK_H
 
+#include <linux/netlink.h>
+
+
 /*
  * This file intended to be included by both kernel and user space
  */
@@ -55,7 +58,41 @@ struct scsi_nl_hdr {
 #define SCSI_NL_TRANSPORT_FC                    1
 #define SCSI_NL_MAX_TRANSPORTS                  2
 
-/* scsi_nl_hdr->msgtype values are defined in each transport */
+/* Transport-based scsi_nl_hdr->msgtype values are defined in each transport */
+
+/*
+ * GENERIC SCSI scsi_nl_hdr->msgtype Values
+ */
+        /* kernel -> user */
+#define SCSI_NL_SHOST_VENDOR                    0x0001
+        /* user -> kernel */
+/* SCSI_NL_SHOST_VENDOR msgtype is kernel->user and user->kernel */
+
+
+/*
+ * Message Structures :
+ */
+
+/* macro to round up message lengths to 8byte boundary */
+#define SCSI_NL_MSGALIGN(len)           (((len) + 7) & ~7)
+
+
+/*
+ * SCSI HOST Vendor Unique messages :
+ *   SCSI_NL_SHOST_VENDOR
+ *
+ * Note: The Vendor Unique message payload will begin directly after
+ *       this structure, with the length of the payload per vmsg_datalen.
+ *
+ * Note: When specifying vendor_id, be sure to read the Vendor Type and ID
+ *   formatting requirements specified below
+ */
+struct scsi_nl_host_vendor_msg {
+        struct scsi_nl_hdr snlh;                /* must be 1st element ! */
+        uint64_t vendor_id;
+        uint16_t host_no;
+        uint16_t vmsg_datalen;
+} __attribute__((aligned(sizeof(uint64_t))));
 
 
 /*
@@ -83,5 +120,28 @@ struct scsi_nl_hdr {
         }
 
 
+#ifdef __KERNEL__
+
+#include <scsi/scsi_host.h>
+
+/* Exported Kernel Interfaces */
+int scsi_nl_add_transport(u8 tport,
+         int (*msg_handler)(struct sk_buff *),
+        void (*event_handler)(struct notifier_block *, unsigned long, void *));
+void scsi_nl_remove_transport(u8 tport);
+
+int scsi_nl_add_driver(u64 vendor_id, struct scsi_host_template *hostt,
+        int (*nlmsg_handler)(struct Scsi_Host *shost, void *payload,
+                                 u32 len, u32 pid),
+        void (*nlevt_handler)(struct notifier_block *nb,
+                                 unsigned long event, void *notify_ptr));
+void scsi_nl_remove_driver(u64 vendor_id);
+
+void scsi_nl_send_transport_msg(u32 pid, struct scsi_nl_hdr *hdr);
+int scsi_nl_send_vendor_msg(u32 pid, unsigned short host_no, u64 vendor_id,
+                         char *data_buf, u32 data_len);
+
+#endif /* __KERNEL__ */
+
 #endif /* SCSI_NETLINK_H */