On 2023/9/28 11:08, Jan Karcher wrote:

On 24/09/2023 17:16, Wen Gu wrote:

quoted

This patch extracts v2-capable logic from the process of registering the
ISM device as an SMC-D device, so that the registration process of other
underlying devices can reuse it.

Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
---
  net/smc/smc_ism.c | 29 ++++++++++++++++++-----------
  net/smc/smc_ism.h |  1 +
  2 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
index 455ae0a..8f1ba74 100644
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c

@@ -69,6 +69,22 @@ bool smc_ism_is_v2_capable(void)

      return smc_ism_v2_capable;
  }
+/* must be called under smcd_dev_list.mutex lock */
+void smc_ism_check_v2_capable(struct smcd_dev *smcd)
+{
+    u8 *system_eid = NULL;
+
+    if (smc_ism_v2_capable)
+        return;
+
+    system_eid = smcd->ops->get_system_eid();
+    if (smcd->ops->supports_v2()) {
+        smc_ism_v2_capable = true;
+        memcpy(smc_ism_v2_system_eid, system_eid,
+               SMC_MAX_EID_LEN);
+    }
+}
+
  /* Set a connection using this DMBE. */
  void smc_ism_set_conn(struct smc_connection *conn)
  {

@@ -423,16 +439,7 @@ static void smcd_register_dev(struct ism_dev *ism)

          smc_pnetid_by_table_smcd(smcd);
      mutex_lock(&smcd_dev_list.mutex);
-    if (list_empty(&smcd_dev_list.list)) {
-        u8 *system_eid = NULL;
-
-        system_eid = smcd->ops->get_system_eid();
-        if (smcd->ops->supports_v2()) {
-            smc_ism_v2_capable = true;
-            memcpy(smc_ism_v2_system_eid, system_eid,
-                   SMC_MAX_EID_LEN);
-        }
-    }
+    smc_ism_check_v2_capable(smcd);

The list_empty check is omitted here which means the smc_ism_check_v2_capable does not touch the list.
So i think the call could be placed prior the mutex_lock.

Good catch. I omitted the list_empty check in this version but forget to remove 'the
lock comments' and place the helper prior to the mutex_lock. It will be fixed.

Thank you.

quoted

      /* sort list: devices without pnetid before devices with pnetid */
      if (smcd->pnetid[0])
          list_add_tail(&smcd->list, &smcd_dev_list.list);

@@ -535,10 +542,10 @@ int smc_ism_init(void)

  {
      int rc = 0;
-#if IS_ENABLED(CONFIG_ISM)
      smc_ism_v2_capable = false;
      memset(smc_ism_v2_system_eid, 0, SMC_MAX_EID_LEN);
+#if IS_ENABLED(CONFIG_ISM)
      rc = ism_register_client(&smc_ism_client);
  #endif
      return rc;

diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h
index 832b2f4..14d2e77 100644
--- a/net/smc/smc_ism.h
+++ b/net/smc/smc_ism.h

@@ -42,6 +42,7 @@ int smc_ism_register_dmb(struct smc_link_group *lgr, int buf_size,

  void smc_ism_get_system_eid(u8 **eid);
  u16 smc_ism_get_chid(struct smcd_dev *dev);
  bool smc_ism_is_v2_capable(void);
+void smc_ism_check_v2_capable(struct smcd_dev *dev);
  int smc_ism_init(void);
  void smc_ism_exit(void);
  int smcd_nl_get_device(struct sk_buff *skb, struct netlink_callback *cb);