Merge tag 'usb-4.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

[cascardo/linux.git] / drivers / misc / cxl / main.c

diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
index d9be23b..62e0dfb 100644 (file)
--- a/drivers/misc/cxl/main.c
+++ b/drivers/misc/cxl/main.c
@@ -243,8 +243,10 @@ struct cxl *cxl_alloc_adapter(void)
        if (dev_set_name(&adapter->dev, "card%i", adapter->adapter_num))
                goto err2;
 
-       return adapter;
+       /* start with context lock taken */
+       atomic_set(&adapter->contexts_num, -1);
 
+       return adapter;
 err2:
        cxl_remove_adapter_nr(adapter);
 err1:
@@ -286,6 +288,44 @@ int cxl_afu_select_best_mode(struct cxl_afu *afu)
        return 0;
 }
 
+int cxl_adapter_context_get(struct cxl *adapter)
+{
+       int rc;
+
+       rc = atomic_inc_unless_negative(&adapter->contexts_num);
+       return rc >= 0 ? 0 : -EBUSY;
+}
+
+void cxl_adapter_context_put(struct cxl *adapter)
+{
+       atomic_dec_if_positive(&adapter->contexts_num);
+}
+
+int cxl_adapter_context_lock(struct cxl *adapter)
+{
+       int rc;
+       /* no active contexts -> contexts_num == 0 */
+       rc = atomic_cmpxchg(&adapter->contexts_num, 0, -1);
+       return rc ? -EBUSY : 0;
+}
+
+void cxl_adapter_context_unlock(struct cxl *adapter)
+{
+       int val = atomic_cmpxchg(&adapter->contexts_num, -1, 0);
+
+       /*
+        * contexts lock taken -> contexts_num == -1
+        * If not true then show a warning and force reset the lock.
+        * This will happen when context_unlock was requested without
+        * doing a context_lock.
+        */
+       if (val != -1) {
+               atomic_set(&adapter->contexts_num, 0);
+               WARN(1, "Adapter context unlocked with %d active contexts",
+                    val);
+       }
+}
+
 static int __init init_cxl(void)
 {
        int rc = 0;