Re: [PATCH 1/2] scsi:netlink support in scsi and fc transports for hba specific messages

[David Somayajulu <david.somayajulu@qlogic.com>]

On Thu, 2008-07-31 at 14:56 -0500, Mike Christie wrote:
> David Somayajulu wrote:
> > This patch adds support to the scsi transport layer for passing hba specific netlink messages to a low level driver. Also support is added to the fc transport, to enable an FC hba driver to post netlink message to a specific user process.

> > +		if (hdr->msgtype == SCSI_NL_HOST_PRIVATE) {
> > +			shost = scsi_host_lookup(hdr->host_no);
> > +			if (!shost) {
> > +				printk(KERN_ERR "%s: scsi_host_lookup failed "
> > +					"host no %u\n", __FUNCTION__, hdr->host_no);
> > +			} else if (shost->hostt->netlink_rcv_msg) {
> > +				err = shost->hostt->netlink_rcv_msg(shost,
> > +					(void *)((char *)hdr+sizeof(*hdr)),
> > +					hdr->msglen, NETLINK_CREDS(skb)->pid);
> > +			}
> > +		}
> 
> Finally getting this done :) Thanks!
> 
> If shost is not null you need to do a scsi_host_put hen you are done 
> with the host.

Incorporating scsi_host_put() as pointed by Mike Christie. (Thanks Mike)

Signed-off-by: David C Somayajulu <david.somayajulu@qlogic.com>
---
 drivers/scsi/scsi_netlink.c      |   14 +++++++
 drivers/scsi/scsi_transport_fc.c |   72 ++++++++++++++++++++++++++++++++++++++
 include/scsi/scsi_host.h         |    6 +++
 include/scsi/scsi_netlink.h      |    3 +-
 include/scsi/scsi_transport_fc.h |    2 +
 5 files changed, 96 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c
index ae7ed9a..fea328c 100644
--- a/drivers/scsi/scsi_netlink.c
+++ b/drivers/scsi/scsi_netlink.c
@@ -24,6 +24,7 @@
 #include <net/sock.h>
 #include <net/netlink.h>
 
+#include <scsi/scsi_host.h>
 #include <scsi/scsi_netlink.h>
 #include "scsi_priv.h"
 
@@ -47,6 +48,7 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 	struct scsi_nl_hdr *hdr;
 	uint32_t rlen;
 	int err;
+	struct Scsi_Host *shost;
 
 	while (skb->len >= NLMSG_SPACE(0)) {
 		err = 0;
@@ -89,6 +91,18 @@ scsi_nl_rcv_msg(struct sk_buff *skb)
 		/*
 		 * We currently don't support anyone sending us a message
 		 */
+		if (hdr->msgtype == SCSI_NL_HOST_PRIVATE) {
+			shost = scsi_host_lookup(hdr->host_no);
+			if (!shost) {
+				printk(KERN_ERR "%s: scsi_host_lookup failed "
+					"host no %u\n", __FUNCTION__, hdr->host_no);
+			} else if (shost->hostt->netlink_rcv_msg) {
+				err = shost->hostt->netlink_rcv_msg(shost,
+					(void *)((char *)hdr+sizeof(*hdr)),
+					hdr->msglen, NETLINK_CREDS(skb)->pid);
+				scsi_host_put(shost);
+			}
+		}
 
 next_msg:
 		if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index cb971f0..d1b38d9 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -627,6 +627,78 @@ EXPORT_SYMBOL(fc_host_post_vendor_event);
 
 
 
+/**
+ * fc_host_post_vendor_event_to_pid - called to post a vendor unique event
+ *			on an fc_host to a specific process
+ * @shost:		host the event occurred on
+ * @event_number:	fc event number obtained from get_fc_event_number()
+ * @data_len:		amount, in bytes, of vendor unique data
+ * @data_buf:		pointer to vendor unique data
+ * @vendor_id:          Vendor id
+ * @pid:		proc id of the receiver
+ *
+ * Notes:
+ *	This routine assumes no locks are held on entry.
+ */
+void
+fc_host_post_vendor_event_to_pid(struct Scsi_Host *shost, u32 event_number,
+		u32 data_len, char * data_buf, u64 vendor_id, uint32_t pid)
+{
+	struct sk_buff *skb;
+	struct nlmsghdr	*nlh;
+	struct fc_nl_event *event;
+	u32 len, skblen;
+	int err;
+
+	if (!scsi_nl_sock) {
+		err = -ENOENT;
+		goto send_vendor_fail;
+	}
+
+	len = FC_NL_MSGALIGN(sizeof(*event) + 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;
+	}
+	event = NLMSG_DATA(nlh);
+
+	INIT_SCSI_NL_HDR(&event->snlh, SCSI_NL_TRANSPORT_FC,
+				FC_NL_ASYNC_EVENT, len);
+	event->seconds = get_seconds();
+	event->vendor_id = vendor_id;
+	event->host_no = shost->host_no;
+	event->event_datalen = data_len;	/* bytes */
+	event->event_num = event_number;
+	event->event_code = FCH_EVT_VENDOR_UNIQUE;
+	memcpy(&event->event_data, data_buf, data_len);
+
+	err = nlmsg_unicast(scsi_nl_sock, skb, pid);
+	if (err && (err != -ESRCH))	/* filter no recipient errors */
+		/* nlmsg_multicast already kfree_skb'd */
+		goto send_vendor_fail;
+
+	return;
+
+send_vendor_fail_skb:
+	kfree_skb(skb);
+send_vendor_fail:
+	printk(KERN_WARNING
+		"%s: Dropped Event : host %d vendor_unique - err %d\n",
+		__FUNCTION__, shost->host_no, err);
+	return;
+}
+EXPORT_SYMBOL(fc_host_post_vendor_event_to_pid);
+
 static __init int fc_transport_init(void)
 {
 	int error;
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 44a55d1..04afe93 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -485,6 +485,12 @@ struct scsi_host_template {
 	 * module_init/module_exit.
 	 */
 	struct list_head legacy_hosts;
+	/*
+	 * passes host specific to netlink messages received on scsi_nl_sock
+	 * to the LLD
+	 */
+	int (* netlink_rcv_msg)(struct Scsi_Host *, void *payload, uint32_t len,
+				uint32_t pid);
 };
 
 /*
diff --git a/include/scsi/scsi_netlink.h b/include/scsi/scsi_netlink.h
index 8c1470c..b32596e 100644
--- a/include/scsi/scsi_netlink.h
+++ b/include/scsi/scsi_netlink.h
@@ -42,6 +42,7 @@ struct scsi_nl_hdr {
 	uint16_t magic;
 	uint16_t msgtype;
 	uint16_t msglen;
+	uint16_t host_no;
 } __attribute__((aligned(sizeof(uint64_t))));
 
 /* scsi_nl_hdr->version value */
@@ -56,7 +57,7 @@ struct scsi_nl_hdr {
 #define SCSI_NL_MAX_TRANSPORTS			2
 
 /* scsi_nl_hdr->msgtype values are defined in each transport */
-
+#define SCSI_NL_HOST_PRIVATE			1
 
 /*
  * Vendor ID:
diff --git a/include/scsi/scsi_transport_fc.h b/include/scsi/scsi_transport_fc.h
index 21018a4..217fdc9 100644
--- a/include/scsi/scsi_transport_fc.h
+++ b/include/scsi/scsi_transport_fc.h
@@ -747,6 +747,8 @@ void fc_host_post_event(struct Scsi_Host *shost, u32 event_number,
 		enum fc_host_event_code event_code, u32 event_data);
 void fc_host_post_vendor_event(struct Scsi_Host *shost, u32 event_number,
 		u32 data_len, char * data_buf, u64 vendor_id);
+void fc_host_post_vendor_event_to_pid(struct Scsi_Host *shost, u32 event_number,
+                u32 data_len, char * data_buf, u64 vendor_id, uint32_t pid);
 	/* Note: when specifying vendor_id to fc_host_post_vendor_event()
 	 *   be sure to read the Vendor Type and ID formatting requirements
 	 *   specified in scsi_netlink.h