net/smc: allocate index for a new link

Add smc_llc_alloc_alt_link() to find a free link index for a new link,
depending on the new link group type. And update constants for the
maximum number of links to 3 (2 symmetric and 1 dangling asymmetric link).
These maximum numbers are the same as used by other implementations of the
SMC-R protocol.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index da3cddb..eb27f2e 100644 (file)
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -128,7 +128,7 @@ struct smc_link {
 /* For now we just allow one parallel link per link group. The SMC protocol
  * allows more (up to 8).
  */
-#define SMC_LINKS_PER_LGR_MAX  1
+#define SMC_LINKS_PER_LGR_MAX  3
 #define SMC_SINGLE_LINK                0
 
 #define SMC_FIRST_CONTACT      1               /* first contact to a peer */

diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index e478a4c..3a25b6e 100644 (file)
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -541,6 +541,30 @@ static int smc_llc_send_message(struct smc_link *link, void *llcbuf)
 
 /********************************* receive ***********************************/
 
+static int smc_llc_alloc_alt_link(struct smc_link_group *lgr,
+                                 enum smc_lgr_type lgr_new_t)
+{
+       int i;
+
+       if (lgr->type == SMC_LGR_SYMMETRIC ||
+           (lgr->type != SMC_LGR_SINGLE &&
+            (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
+             lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)))
+               return -EMLINK;
+
+       if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
+           lgr_new_t == SMC_LGR_ASYMMETRIC_PEER) {
+               for (i = SMC_LINKS_PER_LGR_MAX - 1; i >= 0; i--)
+                       if (lgr->lnk[i].state == SMC_LNK_UNUSED)
+                               return i;
+       } else {
+               for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++)
+                       if (lgr->lnk[i].state == SMC_LNK_UNUSED)
+                               return i;
+       }
+       return -EMLINK;
+}
+
 static void smc_llc_rx_delete_link(struct smc_link *link,
                                   struct smc_llc_msg_del_link *llc)
 {