blk/kernel : skip AIO thread for zero-sized devices

Sometimes devices can be 0-sized, where I/O is impossible.

This change skips _aio_start() in open() if the device size is 0. This avoids unnecessary AIO setup.

This issue was introduced in PR : ceph#60791

Signed-off-by: Jaya Prakash <[email protected]>

Author: Jayaprakash-ibm

src/blk/kernel/KernelDevice.cc

@@ -295,9 +295,13 @@ int KernelDevice::open(const string& p)
     goto out_fail;
   }
 
-  r = _aio_start();
-  if (r < 0) {
-    goto out_fail;
+  if (size > 0) {
+    r = _aio_start();
+    if (r < 0) {
+      goto out_fail;
+    }
+  } else {
+    aio = false;
   }
 
   _discard_update_threads();