David,
I've had a similar patch floating around now for months, but it was
more for messages destined to the transport. It should easily extend
to driver messages too.
My approach had the drivers registering with the scsi netlink module
rather than using the host template (transports don't have a template,
so its either reg/dereg or a static table). Comparing the two, yours
seems cleaner, as the registration/deregistration creates some
headaches.
I'm a little bothered that there's nothing that qualifies the driver
to the shost before invoking the LLDD handler (e.g. driver has a
signature, message header contains signature, and the two must match).
But, perhaps that's livable. One thing yours doesn't do is communicate
netlink events to the consumers, so if they were tracking anything
by pid, they could clean up. You could add this, but it would mean
another template entry point.
I've attached my patch for comparison, although it would need work to
do what you are doing. Anyone else with a preference on the approach ?
-- james s
> -----Original Message-----
> From: linux-scsi-owner@xxxxxxxxxxxxxxx
> [mailto:linux-scsi-owner@xxxxxxxxxxxxxxx] On Behalf Of David
> Somayajulu
> Sent: Wednesday, July 30, 2008 5:54 PM
> To: linux-scsi@xxxxxxxxxxxxxxx
> Cc: David Somayajulu; David Wagner
> Subject: [PATCH 1/2] scsi:netlink support in scsi and fc
> transports for hbaspecific messages
>
> 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.
>
> Signed-off-by: David C Somayajulu <david.somayajulu@xxxxxxxxxx>
> ---
> drivers/scsi/scsi_netlink.c | 13 +++++++
> 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, 95 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/scsi/scsi_netlink.c b/drivers/scsi/scsi_netlink.c
> index ae7ed9a..3bc85c9 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 +91,17 @@ 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);
> + }
> + }
>
> 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
>
> --
> To unsubscribe from this list: send the line "unsubscribe
> linux-scsi" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--- scsi_netlink.c.orig 2008-05-21 10:34:51.602084000 -0400
+++ scsi_netlink.c 2008-05-27 11:33:46.649668000 -0400
@@ -29,7 +29,10 @@
struct sock *scsi_nl_sock = NULL;
EXPORT_SYMBOL_GPL(scsi_nl_sock);
-
+static const struct nl_transport_funcs nl_func[SCSI_NL_MAX_TRANSPORTS]
= {
+ [SCSI_NL_TRANSPORT] = { NULL, NULL },
+ [SCSI_NL_TRANSPORT_FC] = { NULL, NULL },
+};
/**
* scsi_nl_rcv_msg - Receive message handler.
@@ -65,7 +68,7 @@
if (nlh->nlmsg_type != SCSI_TRANSPORT_MSG) {
err = -EBADMSG;
- return;
+ goto next_msg;
}
hdr = NLMSG_DATA(nlh);
@@ -86,10 +89,16 @@
return;
}
- /*
- * We currently don't support anyone sending us a
message
- */
-
+ if (hdr->transport < SCSI_NL_MAX_TRANSPORTS) {
+ if (nl_func[hdr->transport].nl_rcv_msg)
+ nl_func[hdr->transport].nl_rcv_msg(nlh);
+ else
+ printk(KERN_ERR
+ "%s: NULL netlink rcv function
(%d)\n",
+ __func__, hdr->transport);
+ } else
+ printk(KERN_ERR "%s: Invalid transport ID:
%d\n",
+ __func__, hdr->transport);
next_msg:
if ((err) || (nlh->nlmsg_flags & NLM_F_ACK))
netlink_ack(skb, nlh, err);
@@ -110,14 +119,15 @@
scsi_nl_rcv_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct netlink_notify *n = ptr;
+ int i;
if (n->protocol != NETLINK_SCSITRANSPORT)
return NOTIFY_DONE;
- /*
- * Currently, we are not tracking PID's, etc. There is nothing
- * to handle.
- */
+ for (i = 0; i < SCSI_NL_MAX_TRANSPORTS; i++) {
+ if (nl_func[i].nl_rcv_event)
+ nl_func[i].nl_rcv_event(event, ptr);
+ }
return NOTIFY_DONE;
}
@@ -171,4 +181,66 @@
return;
}
+/**
+ * scsi_netlink_add_transport - adds a transport to the SCSI netlink
multiplexer
+ * @transport_id: The transport ID defined in scsi_netlink.h that
+ * corresponds to the transport. This value is used by applications
sending
+ * netlink messages to direct them to the correct transport.
+ * @nl_rcv_msg: The transport's netlink receive message
function.
+ * @nl_rcv_event: The transport's netlink receive event function.
+ *
+ * Description:
+ * This function registers netlink receive functions for a transport
type. Once
+ * called the SCSI netlink code will forward all received netlink
messages with
+ * a transport value of @transport_id to @nl_rcv_func. All SCSI netlink
events
+ * will be forwarded to the @nl_rcv_event function.
+ *
+ * Return:
+ * A return value of zero indicates successful registration of netlink
receive
+ * functions. A non-zero value indicates an error with input
parameters.
+ */
+int
+scsi_netlink_add_transport(int transport_id,
+ int (*nl_rcv_msg)(void *),
+ int (*nl_rcv_event)(unsigned long, void *))
+{
+ if (transport_id >= SCSI_NL_MAX_TRANSPORTS) {
+ printk(KERN_ERR "%s: Invalid transport ID:%d",
+ __func__, transport_id);
+ return EINVAL;
+ }
+ if (nl_func[transport_id].nl_rcv_msg != NULL ||
+ nl_func[transport_id].nl_rcv_event != NULL) {
+ printk(KERN_ERR "%s: Transport (%d) already registered",
+ __func__, transport_id);
+ return EINVAL;
+ }
+ nl_func[transport_id].nl_rcv_msg = nl_rcv_msg;
+ nl_func[transport_id].nl_rcv_event = nl_rcv_event;
+ return 0;
+}
+EXPORT_SYMBOL(scsi_netlink_add_transport);
+/**
+ * scsi_netlink_remove_transport - removes an entry from the netlink
multiplexer
+ * @transport_id: The transport ID defined in scsi_netlink.h that
+ * corresponds to the transport. This value is used by applications
sending
+ * netlink messages to direct them to the correct transport.
+ *
+ * Description:
+ * Once called the transport indicated by @transport_id will no longer
receive
+ * incoming netlink messages from the SCSI transport netlink.
+ */
+int
+scsi_netlink_remove_transport(int transport_id)
+{
+ if (transport_id >= SCSI_NL_MAX_TRANSPORTS) {
+ printk(KERN_ERR "%s: Invalid transport ID:%d",
+ __func__, transport_id);
+ return EINVAL;
+ }
+ nl_func[transport_id].nl_rcv_msg = NULL;
+ nl_func[transport_id].nl_rcv_event = NULL;
+ return 0;
+}
+EXPORT_SYMBOL(scsi_netlink_remove_transport);
--- scsi_netlink.h.orig 2008-05-21 10:37:34.635586000 -0400
+++ scsi_netlink.h 2008-05-27 11:32:23.318744000 -0400
@@ -55,6 +55,11 @@
#define SCSI_NL_TRANSPORT_FC 1
#define SCSI_NL_MAX_TRANSPORTS 2
+struct nl_transport_funcs {
+ int (*nl_rcv_msg)(void *);
+ int (*nl_rcv_event)(unsigned long, void *);
+};
+
/* scsi_nl_hdr->msgtype values are defined in each transport */
@@ -82,6 +87,10 @@
(hdr)->msglen = mlen; \
}
+int scsi_netlink_add_transport(int transport_id,
+ int (*)(void *),
+ int (*)(unsigned long, void *));
+int scsi_netlink_remove_transport(int);
#endif /* SCSI_NETLINK_H */
