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path: root/drivers/misc/cxl/main.c
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Diffstat (limited to 'drivers/misc/cxl/main.c')
-rw-r--r--drivers/misc/cxl/main.c42
1 files changed, 41 insertions, 1 deletions
diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
index d9be23b24aa3..62e0dfb5f15b 100644
--- 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;