[PATCH net 2/3] net/smc: handle unregistered buffers

[Ursula Braun]

From: Karsten Graul <kgr...@linux.ibm.com>

When smc_wr_reg_send() fails then tag (regerr) the affected buffer and
free it in smc_buf_unuse().

Signed-off-by: Karsten Graul <kgr...@linux.ibm.com>
Signed-off-by: Ursula Braun <ubr...@linux.ibm.com>
---
 net/smc/af_smc.c   |  4 +++-
 net/smc/smc_core.c | 22 +++++++++++++++++++---
 net/smc/smc_core.h |  3 ++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index fdb2976117bd..d03b8d29ffc0 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -296,8 +296,10 @@ static void smc_copy_sock_settings_to_smc(struct smc_sock 
*smc)
 static int smc_reg_rmb(struct smc_link *link, struct smc_buf_desc *rmb_desc)
 {
        /* register memory region for new rmb */
-       if (smc_wr_reg_send(link, rmb_desc->mr_rx[SMC_SINGLE_LINK]))
+       if (smc_wr_reg_send(link, rmb_desc->mr_rx[SMC_SINGLE_LINK])) {
+               rmb_desc->regerr = 1;
                return -EFAULT;
+       }
        return 0;
 }
 
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index f44f6803f7ff..d4bd01bb44e1 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -32,6 +32,9 @@
 
 static u32 smc_lgr_num;                        /* unique link group number */
 
+static void smc_buf_free(struct smc_buf_desc *buf_desc, struct smc_link *lnk,
+                        bool is_rmb);
+
 static void smc_lgr_schedule_free_work(struct smc_link_group *lgr)
 {
        /* client link group creation always follows the server link group
@@ -234,9 +237,22 @@ static void smc_buf_unuse(struct smc_connection *conn)
                conn->sndbuf_size = 0;
        }
        if (conn->rmb_desc) {
-               conn->rmb_desc->reused = true;
-               conn->rmb_desc->used = 0;
-               conn->rmbe_size = 0;
+               if (!conn->rmb_desc->regerr) {
+                       conn->rmb_desc->reused = 1;
+                       conn->rmb_desc->used = 0;
+                       conn->rmbe_size = 0;
+               } else {
+                       /* buf registration failed, reuse not possible */
+                       struct smc_link_group *lgr = conn->lgr;
+                       struct smc_link *lnk;
+
+                       write_lock_bh(&lgr->rmbs_lock);
+                       list_del(&conn->rmb_desc->list);
+                       write_unlock_bh(&lgr->rmbs_lock);
+
+                       lnk = &lgr->lnk[SMC_SINGLE_LINK];
+                       smc_buf_free(conn->rmb_desc, lnk, true);
+               }
        }
 }
 
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 07e2a393e6d9..5dfcb15d529f 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -123,7 +123,8 @@ struct smc_buf_desc {
                                                 */
        u32                     order;          /* allocation order */
        u32                     used;           /* currently used / unused */
-       bool                    reused;         /* new created / reused */
+       u8                      reused  : 1;    /* new created / reused */
+       u8                      regerr  : 1;    /* err during registration */
 };
 
 struct smc_rtoken {                            /* address/key of remote RMB */
-- 
2.13.5