[SCSI] fcoe, fnic, libfc: modifies current code paths to use EM anchor list

Modifies current code to use EM anchor list in EM allocation, EM free,
EM reset, exch allocation and exch lookup code paths.

 1. Modifies fc_exch_mgr_alloc to accept EM match function and then
    have allocated EM added to the lport using fc_exch_mgr_add API
    while also updating EM kref for newly added EM.

 2. Updates fc_exch_mgr_free API to accept only lport pointer instead
    EM and then have this API free all EMs of the lport from EM anchor
    list.

 3. Removes single lport pointer link from the EM, which was used in
    associating lport pointer in newly allocated exchange. Instead have
    lport pointer passed along new exchange allocation call path and
    then store passed lport pointer in newly allocated exchange, this
    will allow a single EM instance to be used across more than one
    lport and used in EM reset to reset only lport specific exchanges.

 4. Modifies fc_exch_mgr_reset to reset all EMs from the EM anchor list
    of the lport, adds additional exch lport pointer (ep->lp) check for
    shared EM case to reset exchange specific to a lport requested reset.

 5. Updates exch allocation API fc_exch_alloc to use EM anchor list and
    its anchor match func pointer. The fc_exch_alloc will walk the list
    of EMs until it finds a match, a match will be either null match
    func pointer or call to match function returning true value.

 6. Updates fc_exch_recv to accept incoming frame on local port using
    only lport pointer and frame pointer without specifying EM instance
    of incoming frame. Instead modified fc_exch_recv to locate EM for the
    incoming frame by matching xid of incoming frame against a EM xid range.
    This change was required to use EM list in libfc Rx path and after this
    change the lport fc_exch_mgr pointer emp is not needed anymore, so
    removed emp pointer.

 7. Updates fnic for removed lport emp pointer and above modified libfc APIs
    fc_exch_recv, fc_exch_mgr_alloc and fc_exch_mgr_free.

 8. Removes exch_get and exch_put from libfc_function_template as these
    are no longer needed with EM anchor list and its match function use.
    Also removes its default function fc_exch_get.

A defect this patch introduced regarding the libfc initialization order in
the fnic driver was fixed by Joe Eykholt <jeykholt@cisco.com>.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 117 insertions, 74 deletions

diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index 3ad7f88e7ae3..324589a5cc03 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -65,7 +65,6 @@ struct fc_exch_mgr {
         u16             last_read;      /* last xid allocated for read */
         u32     total_exches;           /* total allocated exchanges */
         struct list_head        ex_list;        /* allocated exchanges list */
-        struct fc_lport *lp;            /* fc device instance */
         mempool_t       *ep_pool;       /* reserve ep's */
 
         /*
@@ -275,8 +274,6 @@ static void fc_exch_release(struct fc_exch *ep)
                 mp = ep->em;
                 if (ep->destructor)
                         ep->destructor(&ep->seq, ep->arg);
-                if (ep->lp->tt.exch_put)
-                        ep->lp->tt.exch_put(ep->lp, mp, ep->xid);
                 WARN_ON(!(ep->esb_stat & ESB_ST_COMPLETE));
                 mempool_free(ep, mp->ep_pool);
         }
@@ -513,17 +510,20 @@ static u16 fc_em_alloc_xid(struct fc_exch_mgr *mp, const struct fc_frame *fp)
         return xid;
 }
 
-/*
- * fc_exch_alloc - allocate an exchange.
- * @mp : ptr to the exchange manager
- * @xid: input xid
+/**
+ * fc_exch_em_alloc() - allocate an exchange from a specified EM.
+ * @lport:      ptr to the local port
+ * @mp:         ptr to the exchange manager
+ * @fp:         ptr to the FC frame
+ * @xid:        input xid
  *
  * if xid is supplied zero then assign next free exchange ID
  * from exchange manager, otherwise use supplied xid.
  * Returns with exch lock held.
  */
-struct fc_exch *fc_exch_alloc(struct fc_exch_mgr *mp,
-                              struct fc_frame *fp, u16 xid)
+static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
+                                        struct fc_exch_mgr *mp,
+                                        struct fc_frame *fp, u16 xid)
 {
         struct fc_exch *ep;
 
@@ -566,7 +566,7 @@ struct fc_exch *fc_exch_alloc(struct fc_exch_mgr *mp,
          */
         ep->oxid = ep->xid = xid;
         ep->em = mp;
-        ep->lp = mp->lp;
+        ep->lp = lport;
         ep->f_ctl = FC_FC_FIRST_SEQ;    /* next seq is first seq */
         ep->rxid = FC_XID_UNKNOWN;
         ep->class = mp->class;
@@ -579,6 +579,31 @@ err:
         mempool_free(ep, mp->ep_pool);
         return NULL;
 }
+
+/**
+ * fc_exch_alloc() - allocate an exchange.
+ * @lport:      ptr to the local port
+ * @fp:         ptr to the FC frame
+ *
+ * This function walks the list of the exchange manager(EM)
+ * anchors to select a EM for new exchange allocation. The
+ * EM is selected having either a NULL match function pointer
+ * or call to match function returning true.
+ */
+struct fc_exch *fc_exch_alloc(struct fc_lport *lport, struct fc_frame *fp)
+{
+        struct fc_exch_mgr_anchor *ema;
+        struct fc_exch *ep;
+
+        list_for_each_entry(ema, &lport->ema_list, ema_list) {
+                if (!ema->match || ema->match(fp)) {
+                        ep = fc_exch_em_alloc(lport, ema->mp, fp, 0);
+                        if (ep)
+                                return ep;
+                }
+        }
+        return NULL;
+}
 EXPORT_SYMBOL(fc_exch_alloc);
 
 /*
@@ -617,12 +642,14 @@ EXPORT_SYMBOL(fc_exch_done);
  * Allocate a new exchange as responder.
  * Sets the responder ID in the frame header.
  */
-static struct fc_exch *fc_exch_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
+static struct fc_exch *fc_exch_resp(struct fc_lport *lport,
+                                    struct fc_exch_mgr *mp,
+                                    struct fc_frame *fp)
 {
         struct fc_exch *ep;
         struct fc_frame_header *fh;
 
-        ep = mp->lp->tt.exch_get(mp->lp, fp);
+        ep = fc_exch_alloc(lport, fp);
         if (ep) {
                 ep->class = fc_frame_class(fp);
 
@@ -648,7 +675,7 @@ static struct fc_exch *fc_exch_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
                         ep->esb_stat &= ~ESB_ST_SEQ_INIT;
 
                 fc_exch_hold(ep);       /* hold for caller */
-                spin_unlock_bh(&ep->ex_lock);   /* lock from exch_get */
+                spin_unlock_bh(&ep->ex_lock);   /* lock from fc_exch_alloc */
         }
         return ep;
 }
@@ -658,7 +685,8 @@ static struct fc_exch *fc_exch_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
  * If fc_pf_rjt_reason is FC_RJT_NONE then this function will have a hold
  * on the ep that should be released by the caller.
  */
-static enum fc_pf_rjt_reason fc_seq_lookup_recip(struct fc_exch_mgr *mp,
+static enum fc_pf_rjt_reason fc_seq_lookup_recip(struct fc_lport *lport,
+                                                 struct fc_exch_mgr *mp,
                                                  struct fc_frame *fp)
 {
         struct fc_frame_header *fh = fc_frame_header_get(fp);
@@ -712,7 +740,7 @@ static enum fc_pf_rjt_reason fc_seq_lookup_recip(struct fc_exch_mgr *mp,
                                 reject = FC_RJT_RX_ID;
                                 goto rel;
                         }
-                        ep = fc_exch_resp(mp, fp);
+                        ep = fc_exch_resp(lport, mp, fp);
                         if (!ep) {
                                 reject = FC_RJT_EXCH_EST;       /* XXX */
                                 goto out;
@@ -1103,7 +1131,7 @@ static void fc_exch_recv_req(struct fc_lport *lp, struct fc_exch_mgr *mp,
         enum fc_pf_rjt_reason reject;
 
         fr_seq(fp) = NULL;
-        reject = fc_seq_lookup_recip(mp, fp);
+        reject = fc_seq_lookup_recip(lp, mp, fp);
         if (reject == FC_RJT_NONE) {
                 sp = fr_seq(fp);        /* sequence will be held */
                 ep = fc_seq_exch(sp);
@@ -1467,29 +1495,34 @@ void fc_exch_mgr_reset(struct fc_lport *lp, u32 sid, u32 did)
 {
         struct fc_exch *ep;
         struct fc_exch *next;
-        struct fc_exch_mgr *mp = lp->emp;
+        struct fc_exch_mgr *mp;
+        struct fc_exch_mgr_anchor *ema;
 
-        spin_lock_bh(&mp->em_lock);
+        list_for_each_entry(ema, &lp->ema_list, ema_list) {
+                mp = ema->mp;
+                spin_lock_bh(&mp->em_lock);
 restart:
-        list_for_each_entry_safe(ep, next, &mp->ex_list, ex_list) {
-                if ((sid == 0 || sid == ep->sid) &&
-                    (did == 0 || did == ep->did)) {
-                        fc_exch_hold(ep);
-                        spin_unlock_bh(&mp->em_lock);
-
-                        fc_exch_reset(ep);
-
-                        fc_exch_release(ep);
-                        spin_lock_bh(&mp->em_lock);
-
-                        /*
-                         * must restart loop incase while lock was down
-                         * multiple eps were released.
-                         */
-                        goto restart;
+                list_for_each_entry_safe(ep, next, &mp->ex_list, ex_list) {
+                        if ((lp == ep->lp) &&
+                            (sid == 0 || sid == ep->sid) &&
+                            (did == 0 || did == ep->did)) {
+                                fc_exch_hold(ep);
+                                spin_unlock_bh(&mp->em_lock);
+
+                                fc_exch_reset(ep);
+
+                                fc_exch_release(ep);
+                                spin_lock_bh(&mp->em_lock);
+
+                                /*
+                                 * must restart loop incase while lock
+                                 * was down multiple eps were released.
+                                 */
+                                goto restart;
+                        }
                 }
+                spin_unlock_bh(&mp->em_lock);
         }
-        spin_unlock_bh(&mp->em_lock);
 }
 EXPORT_SYMBOL(fc_exch_mgr_reset);
 
@@ -1778,7 +1811,8 @@ EXPORT_SYMBOL(fc_exch_mgr_del);
 
 struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lp,
                                       enum fc_class class,
-                                      u16 min_xid, u16 max_xid)
+                                      u16 min_xid, u16 max_xid,
+                                      bool (*match)(struct fc_frame *))
 {
         struct fc_exch_mgr *mp;
         size_t len;
@@ -1803,7 +1837,6 @@ struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lp,
         mp->class = class;
         mp->total_exches = 0;
         mp->exches = (struct fc_exch **)(mp + 1);
-        mp->lp = lp;
         /* adjust em exch xid range for offload */
         mp->min_xid = min_xid;
         mp->max_xid = max_xid;
@@ -1826,6 +1859,18 @@ struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lp,
         if (!mp->ep_pool)
                 goto free_mp;
 
+        kref_init(&mp->kref);
+        if (!fc_exch_mgr_add(lp, mp, match)) {
+                mempool_destroy(mp->ep_pool);
+                goto free_mp;
+        }
+
+        /*
+         * Above kref_init() sets mp->kref to 1 and then
+         * call to fc_exch_mgr_add incremented mp->kref again,
+         * so adjust that extra increment.
+         */
+        kref_put(&mp->kref, fc_exch_mgr_destroy);
         return mp;
 
 free_mp:
@@ -1834,27 +1879,15 @@ free_mp:
 }
 EXPORT_SYMBOL(fc_exch_mgr_alloc);
 
-void fc_exch_mgr_free(struct fc_exch_mgr *mp)
+void fc_exch_mgr_free(struct fc_lport *lport)
 {
-        WARN_ON(!mp);
-        /*
-         * The total exch count must be zero
-         * before freeing exchange manager.
-         */
-        WARN_ON(mp->total_exches != 0);
-        mempool_destroy(mp->ep_pool);
-        kfree(mp);
+        struct fc_exch_mgr_anchor *ema, *next;
+
+        list_for_each_entry_safe(ema, next, &lport->ema_list, ema_list)
+                fc_exch_mgr_del(ema);
 }
 EXPORT_SYMBOL(fc_exch_mgr_free);
 
-struct fc_exch *fc_exch_get(struct fc_lport *lp, struct fc_frame *fp)
-{
-        if (!lp || !lp->emp)
-                return NULL;
-
-        return fc_exch_alloc(lp->emp, fp, 0);
-}
-EXPORT_SYMBOL(fc_exch_get);
 
 struct fc_seq *fc_exch_seq_send(struct fc_lport *lp,
                                 struct fc_frame *fp,
@@ -1869,7 +1902,7 @@ struct fc_seq *fc_exch_seq_send(struct fc_lport *lp,
         struct fc_frame_header *fh;
         int rc = 1;
 
-        ep = lp->tt.exch_get(lp, fp);
+        ep = fc_exch_alloc(lp, fp);
         if (!ep) {
                 fc_frame_free(fp);
                 return NULL;
@@ -1914,24 +1947,44 @@ EXPORT_SYMBOL(fc_exch_seq_send);
 /*
  * Receive a frame
  */
-void fc_exch_recv(struct fc_lport *lp, struct fc_exch_mgr *mp,
-                  struct fc_frame *fp)
+void fc_exch_recv(struct fc_lport *lp, struct fc_frame *fp)
 {
         struct fc_frame_header *fh = fc_frame_header_get(fp);
-        u32 f_ctl;
+        struct fc_exch_mgr_anchor *ema;
+        u32 f_ctl, found = 0;
+        u16 oxid;
 
         /* lport lock ? */
-        if (!lp || !mp || lp->state == LPORT_ST_DISABLED) {
+        if (!lp || lp->state == LPORT_ST_DISABLED) {
                 FC_LPORT_DBG(lp, "Receiving frames for an lport that "
                              "has not been initialized correctly\n");
                 fc_frame_free(fp);
                 return;
         }
 
+        f_ctl = ntoh24(fh->fh_f_ctl);
+        oxid = ntohs(fh->fh_ox_id);
+        if (f_ctl & FC_FC_EX_CTX) {
+                list_for_each_entry(ema, &lp->ema_list, ema_list) {
+                        if ((oxid >= ema->mp->min_xid) &&
+                            (oxid <= ema->mp->max_xid)) {
+                                found = 1;
+                                break;
+                        }
+                }
+
+                if (!found) {
+                        FC_LPORT_DBG(lp, "Received response for out "
+                                     "of range oxid:%hx\n", oxid);
+                        fc_frame_free(fp);
+                        return;
+                }
+        } else
+                ema = list_entry(lp->ema_list.prev, typeof(*ema), ema_list);
+
         /*
          * If frame is marked invalid, just drop it.
          */
-        f_ctl = ntoh24(fh->fh_f_ctl);
         switch (fr_eof(fp)) {
         case FC_EOF_T:
                 if (f_ctl & FC_FC_END_SEQ)
@@ -1939,34 +1992,24 @@ void fc_exch_recv(struct fc_lport *lp, struct fc_exch_mgr *mp,
                 /* fall through */
         case FC_EOF_N:
                 if (fh->fh_type == FC_TYPE_BLS)
-                        fc_exch_recv_bls(mp, fp);
+                        fc_exch_recv_bls(ema->mp, fp);
                 else if ((f_ctl & (FC_FC_EX_CTX | FC_FC_SEQ_CTX)) ==
                          FC_FC_EX_CTX)
-                        fc_exch_recv_seq_resp(mp, fp);
+                        fc_exch_recv_seq_resp(ema->mp, fp);
                 else if (f_ctl & FC_FC_SEQ_CTX)
-                        fc_exch_recv_resp(mp, fp);
+                        fc_exch_recv_resp(ema->mp, fp);
                 else
-                        fc_exch_recv_req(lp, mp, fp);
+                        fc_exch_recv_req(lp, ema->mp, fp);
                 break;
         default:
                 FC_LPORT_DBG(lp, "dropping invalid frame (eof %x)", fr_eof(fp));
                 fc_frame_free(fp);
-                break;
         }
 }
 EXPORT_SYMBOL(fc_exch_recv);
 
 int fc_exch_init(struct fc_lport *lp)
 {
-        if (!lp->tt.exch_get) {
-                /*
-                 *  exch_put() should be NULL if
-                 *  exch_get() is NULL
-                 */
-                WARN_ON(lp->tt.exch_put);
-                lp->tt.exch_get = fc_exch_get;
-        }
-
         if (!lp->tt.seq_start_next)
                 lp->tt.seq_start_next = fc_seq_start_next;