[PULL 22/47] vfio/common: return early if space isn't empty

Cédric Le Goater posted 47 patches 11 months, 1 week ago
Maintainers: Paolo Bonzini <pbonzini@redhat.com>, Yi Liu <yi.l.liu@intel.com>, Eric Auger <eric.auger@redhat.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, Peter Maydell <peter.maydell@linaro.org>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Nicholas Piggin <npiggin@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, "Cédric Le Goater" <clg@kaod.org>, David Gibson <david@gibson.dropbear.id.au>, Harsh Prateek Bora <harshpb@linux.ibm.com>, David Hildenbrand <david@redhat.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Eric Farman <farman@linux.ibm.com>, Thomas Huth <thuth@redhat.com>, Alex Williamson <alex.williamson@redhat.com>, Tony Krowiak <akrowiak@linux.ibm.com>, Jason Herne <jjherne@linux.ibm.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, "Daniel P. Berrangé" <berrange@redhat.com>
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[PULL 22/47] vfio/common: return early if space isn't empty
Posted by Cédric Le Goater 11 months, 1 week ago
From: Zhenzhong Duan <zhenzhong.duan@intel.com>

This is a trivial optimization. If there is active container in space,
vfio_reset_handler will never be unregistered. So revert the check of
space->containers and return early.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/common.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 572ae7c934070b9fdc66915f6831fb0fa1323941..934f4f5446e9fc7decd991148f3f7992bf653a4a 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1462,10 +1462,13 @@ VFIOAddressSpace *vfio_get_address_space(AddressSpace *as)
 
 void vfio_put_address_space(VFIOAddressSpace *space)
 {
-    if (QLIST_EMPTY(&space->containers)) {
-        QLIST_REMOVE(space, list);
-        g_free(space);
+    if (!QLIST_EMPTY(&space->containers)) {
+        return;
     }
+
+    QLIST_REMOVE(space, list);
+    g_free(space);
+
     if (QLIST_EMPTY(&vfio_address_spaces)) {
         qemu_unregister_reset(vfio_reset_handler, NULL);
     }
-- 
2.43.0