qemu_domain: Drop namespace check from top level functions

[libvirt] [PATCH] qemu_domain: Drop namespace check from top level functions

Posted by Michal Privoznik 5 years, 7 months ago

In some cases we are checking if the mount namespace is enabled
at two places: one is at the beginning of exported function (e.g.
qemuDomainNamespaceSetupDisk()) and the other is at the beginning
of qemuDomainNamespaceMknodPaths() which is called from the
former function anyway. Then we have some other functions which
rely on the later check solely.

In order to compensate for possibly needles function call,
qemuDomainNamespaceMknodPaths() returns early if @npaths is zero.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_domain.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 5329899b13..15325aa4c1 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -12428,7 +12428,8 @@ qemuDomainNamespaceMknodPaths(virDomainObjPtr vm,
     int ret = -1;
     size_t i;
 
-    if (!qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT))
+    if (!qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) ||
+        !npaths)
         return 0;
 
     cfg = virQEMUDriverGetConfig(driver);
@@ -12521,9 +12522,6 @@ qemuDomainNamespaceSetupDisk(virDomainObjPtr vm,
     char *dmPath = NULL;
     int ret = -1;
 
-    if (!qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT))
-        return 0;
-
     for (next = src; virStorageSourceIsBacking(next); next = next->backingStore) {
         if (virStorageSourceIsEmpty(next) ||
             !virStorageSourceIsLocalStorage(next)) {
@@ -12574,9 +12572,6 @@ qemuDomainNamespaceSetupHostdev(virDomainObjPtr vm,
     char **paths = NULL;
     size_t i, npaths = 0;
 
-    if (!qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT))
-        return 0;
-
     if (qemuDomainGetHostdevPath(NULL, hostdev, false, &npaths, &paths, NULL) < 0)
         goto cleanup;
 
@@ -12600,9 +12595,6 @@ qemuDomainNamespaceTeardownHostdev(virDomainObjPtr vm,
     char **paths = NULL;
     size_t i, npaths = 0;
 
-    if (!qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT))
-        return 0;
-
     if (qemuDomainGetHostdevPath(vm->def, hostdev, true,
                                  &npaths, &paths, NULL) < 0)
         goto cleanup;
-- 
2.16.4

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Re: [libvirt] [PATCH] qemu_domain: Drop namespace check from top level functions

Posted by John Ferlan 5 years, 7 months ago


On 09/07/2018 08:05 AM, Michal Privoznik wrote:
> In some cases we are checking if the mount namespace is enabled
> at two places: one is at the beginning of exported function (e.g.
> qemuDomainNamespaceSetupDisk()) and the other is at the beginning
> of qemuDomainNamespaceMknodPaths() which is called from the
> former function anyway. Then we have some other functions which
> rely on the later check solely.
> 
> In order to compensate for possibly needles function call,

needless

> qemuDomainNamespaceMknodPaths() returns early if @npaths is zero.
> 
> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> ---
>  src/qemu/qemu_domain.c | 12 ++----------
>  1 file changed, 2 insertions(+), 10 deletions(-)
> 

Even though my personal preference for npaths == 0, what's here is
consistent with the same check in qemuDomainNamespaceUnlinkPaths.

Reviewed-by: John Ferlan <jferlan@redhat.com>

John

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