scsi: fcoe: Embed fc_rport_priv in fcoe_rport structure

Gcc-9 complains for a memset across pointer boundaries, which happens as
the code tries to allocate a flexible array on the stack.  Turns out we
cannot do this without relying on gcc-isms, so with this patch we'll embed
the fc_rport_priv structure into fcoe_rport, can use the normal
'container_of' outcast, and will only have to do a memset over one
structure.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

3 files changed, 25 insertions, 32 deletions

diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c
index 1a85fe9e4b7b..fc32b5d76821 100644
--- a/drivers/scsi/fcoe/fcoe_ctlr.c
+++ b/drivers/scsi/fcoe/fcoe_ctlr.c
@@ -2005,7 +2005,7 @@ EXPORT_SYMBOL_GPL(fcoe_wwn_from_mac);
  */
 static inline struct fcoe_rport *fcoe_ctlr_rport(struct fc_rport_priv *rdata)
 {
-        return (struct fcoe_rport *)(rdata + 1);
+        return container_of(rdata, struct fcoe_rport, rdata);
 }
 
 /**
@@ -2269,7 +2269,7 @@ static void fcoe_ctlr_vn_start(struct fcoe_ctlr *fip)
  */
 static int fcoe_ctlr_vn_parse(struct fcoe_ctlr *fip,
                               struct sk_buff *skb,
-                              struct fc_rport_priv *rdata)
+                              struct fcoe_rport *frport)
 {
         struct fip_header *fiph;
         struct fip_desc *desc = NULL;
@@ -2277,16 +2277,12 @@ static int fcoe_ctlr_vn_parse(struct fcoe_ctlr *fip,
         struct fip_wwn_desc *wwn = NULL;
         struct fip_vn_desc *vn = NULL;
         struct fip_size_desc *size = NULL;
-        struct fcoe_rport *frport;
         size_t rlen;
         size_t dlen;
         u32 desc_mask = 0;
         u32 dtype;
         u8 sub;
 
-        memset(rdata, 0, sizeof(*rdata) + sizeof(*frport));
-        frport = fcoe_ctlr_rport(rdata);
-
         fiph = (struct fip_header *)skb->data;
         frport->flags = ntohs(fiph->fip_flags);
 
@@ -2349,15 +2345,17 @@ static int fcoe_ctlr_vn_parse(struct fcoe_ctlr *fip,
                         if (dlen != sizeof(struct fip_wwn_desc))
                                 goto len_err;
                         wwn = (struct fip_wwn_desc *)desc;
-                        rdata->ids.node_name = get_unaligned_be64(&wwn->fd_wwn);
+                        frport->rdata.ids.node_name =
+                                get_unaligned_be64(&wwn->fd_wwn);
                         break;
                 case FIP_DT_VN_ID:
                         if (dlen != sizeof(struct fip_vn_desc))
                                 goto len_err;
                         vn = (struct fip_vn_desc *)desc;
                         memcpy(frport->vn_mac, vn->fd_mac, ETH_ALEN);
-                        rdata->ids.port_id = ntoh24(vn->fd_fc_id);
-                        rdata->ids.port_name = get_unaligned_be64(&vn->fd_wwpn);
+                        frport->rdata.ids.port_id = ntoh24(vn->fd_fc_id);
+                        frport->rdata.ids.port_name =
+                                get_unaligned_be64(&vn->fd_wwpn);
                         break;
                 case FIP_DT_FC4F:
                         if (dlen != sizeof(struct fip_fc4_feat))
@@ -2738,10 +2736,7 @@ static int fcoe_ctlr_vn_recv(struct fcoe_ctlr *fip, struct sk_buff *skb)
 {
         struct fip_header *fiph;
         enum fip_vn2vn_subcode sub;
-        struct {
-                struct fc_rport_priv rdata;
-                struct fcoe_rport frport;
-        } buf;
+        struct fcoe_rport frport = { };
         int rc, vlan_id = 0;
 
         fiph = (struct fip_header *)skb->data;
@@ -2757,7 +2752,7 @@ static int fcoe_ctlr_vn_recv(struct fcoe_ctlr *fip, struct sk_buff *skb)
                 goto drop;
         }
 
-        rc = fcoe_ctlr_vn_parse(fip, skb, &buf.rdata);
+        rc = fcoe_ctlr_vn_parse(fip, skb, &frport);
         if (rc) {
                 LIBFCOE_FIP_DBG(fip, "vn_recv vn_parse error %d\n", rc);
                 goto drop;
@@ -2766,19 +2761,19 @@ static int fcoe_ctlr_vn_recv(struct fcoe_ctlr *fip, struct sk_buff *skb)
         mutex_lock(&fip->ctlr_mutex);
         switch (sub) {
         case FIP_SC_VN_PROBE_REQ:
-                fcoe_ctlr_vn_probe_req(fip, &buf.rdata);
+                fcoe_ctlr_vn_probe_req(fip, &frport.rdata);
                 break;
         case FIP_SC_VN_PROBE_REP:
-                fcoe_ctlr_vn_probe_reply(fip, &buf.rdata);
+                fcoe_ctlr_vn_probe_reply(fip, &frport.rdata);
                 break;
         case FIP_SC_VN_CLAIM_NOTIFY:
-                fcoe_ctlr_vn_claim_notify(fip, &buf.rdata);
+                fcoe_ctlr_vn_claim_notify(fip, &frport.rdata);
                 break;
         case FIP_SC_VN_CLAIM_REP:
-                fcoe_ctlr_vn_claim_resp(fip, &buf.rdata);
+                fcoe_ctlr_vn_claim_resp(fip, &frport.rdata);
                 break;
         case FIP_SC_VN_BEACON:
-                fcoe_ctlr_vn_beacon(fip, &buf.rdata);
+                fcoe_ctlr_vn_beacon(fip, &frport.rdata);
                 break;
         default:
                 LIBFCOE_FIP_DBG(fip, "vn_recv unknown subcode %d\n", sub);
@@ -2802,22 +2797,18 @@ drop:
  */
 static int fcoe_ctlr_vlan_parse(struct fcoe_ctlr *fip,
                               struct sk_buff *skb,
-                              struct fc_rport_priv *rdata)
+                              struct fcoe_rport *frport)
 {
         struct fip_header *fiph;
         struct fip_desc *desc = NULL;
         struct fip_mac_desc *macd = NULL;
         struct fip_wwn_desc *wwn = NULL;
-        struct fcoe_rport *frport;
         size_t rlen;
         size_t dlen;
         u32 desc_mask = 0;
         u32 dtype;
         u8 sub;
 
-        memset(rdata, 0, sizeof(*rdata) + sizeof(*frport));
-        frport = fcoe_ctlr_rport(rdata);
-
         fiph = (struct fip_header *)skb->data;
         frport->flags = ntohs(fiph->fip_flags);
 
@@ -2871,7 +2862,8 @@ static int fcoe_ctlr_vlan_parse(struct fcoe_ctlr *fip,
                         if (dlen != sizeof(struct fip_wwn_desc))
                                 goto len_err;
                         wwn = (struct fip_wwn_desc *)desc;
-                        rdata->ids.node_name = get_unaligned_be64(&wwn->fd_wwn);
+                        frport->rdata.ids.node_name =
+                                get_unaligned_be64(&wwn->fd_wwn);
                         break;
                 default:
                         LIBFCOE_FIP_DBG(fip, "unexpected descriptor type %x "
@@ -2982,22 +2974,19 @@ static int fcoe_ctlr_vlan_recv(struct fcoe_ctlr *fip, struct sk_buff *skb)
 {
         struct fip_header *fiph;
         enum fip_vlan_subcode sub;
-        struct {
-                struct fc_rport_priv rdata;
-                struct fcoe_rport frport;
-        } buf;
+        struct fcoe_rport frport = { };
         int rc;
 
         fiph = (struct fip_header *)skb->data;
         sub = fiph->fip_subcode;
-        rc = fcoe_ctlr_vlan_parse(fip, skb, &buf.rdata);
+        rc = fcoe_ctlr_vlan_parse(fip, skb, &frport);
         if (rc) {
                 LIBFCOE_FIP_DBG(fip, "vlan_recv vlan_parse error %d\n", rc);
                 goto drop;
         }
         mutex_lock(&fip->ctlr_mutex);
         if (sub == FIP_SC_VL_REQ)
-                fcoe_ctlr_vlan_disc_reply(fip, &buf.rdata);
+                fcoe_ctlr_vlan_disc_reply(fip, &frport.rdata);
         mutex_unlock(&fip->ctlr_mutex);
 
 drop:
diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index e0f3852fdad1..da6e97d8dc3b 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -128,6 +128,7 @@ EXPORT_SYMBOL(fc_rport_lookup);
 struct fc_rport_priv *fc_rport_create(struct fc_lport *lport, u32 port_id)
 {
         struct fc_rport_priv *rdata;
+        size_t rport_priv_size = sizeof(*rdata);
 
         lockdep_assert_held(&lport->disc.disc_mutex);
 
@@ -135,7 +136,9 @@ struct fc_rport_priv *fc_rport_create(struct fc_lport *lport, u32 port_id)
         if (rdata)
                 return rdata;
 
-        rdata = kzalloc(sizeof(*rdata) + lport->rport_priv_size, GFP_KERNEL);
+        if (lport->rport_priv_size > 0)
+                rport_priv_size = lport->rport_priv_size;
+        rdata = kzalloc(rport_priv_size, GFP_KERNEL);
         if (!rdata)
                 return NULL;
 
diff --git a/include/scsi/libfcoe.h b/include/scsi/libfcoe.h
index dc14b52577f7..2568cb0627ec 100644
--- a/include/scsi/libfcoe.h
+++ b/include/scsi/libfcoe.h
@@ -229,6 +229,7 @@ struct fcoe_fcf {
  * @vn_mac:     VN_Node assigned MAC address for data
  */
 struct fcoe_rport {
+        struct fc_rport_priv rdata;
         unsigned long time;
         u16 fcoe_len;
         u16 flags;