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authorJoe Eykholt <jeykholt@cisco.com>2011-01-28 16:04:02 -0800
committerJames Bottomley <James.Bottomley@suse.de>2011-02-12 11:00:40 -0600
commit96ad846445ae33dcae1805b68752e3d5c840e3ed (patch)
treee73ea227c24d90654d58f0cfbec00f689bdac081 /drivers/scsi/libfc/fc_libfc.c
parent55204909bb687c997d5601e9f24a25cf9e915d78 (diff)
downloadlinux-96ad846445ae33dcae1805b68752e3d5c840e3ed.tar.bz2
[SCSI] libfc: add hook for FC-4 provider registration
Allow FC-4 provider modules to hook into libfc, mostly for targets. This should allow any FC-4 module to handle PRLI requests and maintain process-association states. Each provider registers its ops with libfc and then will be called for any incoming PRLI for that FC-4 type on any instance. The provider can decide whether to handle that particular instance using any method it likes, such as ACLs or other configuration information. A count is kept of the number of successful PRLIs from the remote port. Providers are called back with an implicit PRLO when the remote port is about to be deleted or has been reset. fc_lport_recv_req() now sends incoming FC-4 requests to FC-4 providers, and there is a built-in provider always registered for handling incoming ELS requests. The call to provider recv() routines uses rcu_read_lock() so that providers aren't removed during the call. That lock is very cheap and shouldn't affect any performance on ELS requests. Providers can rely on the RCU lock to protect a session lookup as well. Signed-off-by: Joe Eykholt <jeykholt@cisco.com> Signed-off-by: Robert Love <robert.w.love@intel.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/libfc/fc_libfc.c')
-rw-r--r--drivers/scsi/libfc/fc_libfc.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/drivers/scsi/libfc/fc_libfc.c b/drivers/scsi/libfc/fc_libfc.c
index 6a48c28e4420..ae3abef6523e 100644
--- a/drivers/scsi/libfc/fc_libfc.c
+++ b/drivers/scsi/libfc/fc_libfc.c
@@ -35,6 +35,23 @@ unsigned int fc_debug_logging;
module_param_named(debug_logging, fc_debug_logging, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(debug_logging, "a bit mask of logging levels");
+DEFINE_MUTEX(fc_prov_mutex);
+
+/*
+ * Providers which primarily send requests and PRLIs.
+ */
+struct fc4_prov *fc_active_prov[FC_FC4_PROV_SIZE] = {
+ [0] = &fc_rport_t0_prov,
+ [FC_TYPE_FCP] = &fc_rport_fcp_init,
+};
+
+/*
+ * Providers which receive requests.
+ */
+struct fc4_prov *fc_passive_prov[FC_FC4_PROV_SIZE] = {
+ [FC_TYPE_ELS] = &fc_lport_els_prov,
+};
+
/**
* libfc_init() - Initialize libfc.ko
*/
@@ -210,3 +227,46 @@ void fc_fill_reply_hdr(struct fc_frame *fp, const struct fc_frame *in_fp,
fc_fill_hdr(fp, in_fp, r_ctl, FC_FCTL_RESP, 0, parm_offset);
}
EXPORT_SYMBOL(fc_fill_reply_hdr);
+
+/**
+ * fc_fc4_register_provider() - register FC-4 upper-level provider.
+ * @type: FC-4 type, such as FC_TYPE_FCP
+ * @prov: structure describing provider including ops vector.
+ *
+ * Returns 0 on success, negative error otherwise.
+ */
+int fc_fc4_register_provider(enum fc_fh_type type, struct fc4_prov *prov)
+{
+ struct fc4_prov **prov_entry;
+ int ret = 0;
+
+ if (type >= FC_FC4_PROV_SIZE)
+ return -EINVAL;
+ mutex_lock(&fc_prov_mutex);
+ prov_entry = (prov->recv ? fc_passive_prov : fc_active_prov) + type;
+ if (*prov_entry)
+ ret = -EBUSY;
+ else
+ *prov_entry = prov;
+ mutex_unlock(&fc_prov_mutex);
+ return ret;
+}
+EXPORT_SYMBOL(fc_fc4_register_provider);
+
+/**
+ * fc_fc4_deregister_provider() - deregister FC-4 upper-level provider.
+ * @type: FC-4 type, such as FC_TYPE_FCP
+ * @prov: structure describing provider including ops vector.
+ */
+void fc_fc4_deregister_provider(enum fc_fh_type type, struct fc4_prov *prov)
+{
+ BUG_ON(type >= FC_FC4_PROV_SIZE);
+ mutex_lock(&fc_prov_mutex);
+ if (prov->recv)
+ rcu_assign_pointer(fc_passive_prov[type], NULL);
+ else
+ rcu_assign_pointer(fc_active_prov[type], NULL);
+ mutex_unlock(&fc_prov_mutex);
+ synchronize_rcu();
+}
+EXPORT_SYMBOL(fc_fc4_deregister_provider);