[libvirt] [REPOST PATCH v2 3/9] qemu: Adjust maxparams logic for qemuDomainGetBlockIoTune

[John Ferlan]

Rather than using negative logic and setting the maxparams to a lesser
value based on which capabilities exist, alter the logic to modify the
maxparams based on a base value plus the found capabilities. Reduces the
chance that some backported feature produces an incorrect value.

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 src/qemu/qemu_driver.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index d039255..87d219f 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -112,9 +112,12 @@ VIR_LOG_INIT("qemu.qemu_driver");
 
 #define QEMU_NB_MEM_PARAM  3
 
-#define QEMU_NB_BLOCK_IO_TUNE_PARAM  6
-#define QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX  13
-#define QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX_LENGTH 19
+#define QEMU_NB_BLOCK_IO_TUNE_BASE_PARAMS 6
+#define QEMU_NB_BLOCK_IO_TUNE_MAX_PARAMS 7
+#define QEMU_NB_BLOCK_IO_TUNE_LENGTH_PARAMS 6
+#define QEMU_NB_BLOCK_IO_TUNE_ALL_PARAMS (QEMU_NB_BLOCK_IO_TUNE_BASE_PARAMS + \
+                                          QEMU_NB_BLOCK_IO_TUNE_MAX_PARAMS + \
+                                          QEMU_NB_BLOCK_IO_TUNE_LENGTH_PARAMS)
 
 #define QEMU_NB_NUMA_PARAM 2
 
@@ -17719,7 +17722,7 @@ qemuDomainGetBlockIoTune(virDomainPtr dom,
     virDomainBlockIoTuneInfo reply;
     char *device = NULL;
     int ret = -1;
-    int maxparams = QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX_LENGTH;
+    int maxparams;
 
     virCheckFlags(VIR_DOMAIN_AFFECT_LIVE |
                   VIR_DOMAIN_AFFECT_CONFIG |
@@ -17753,11 +17756,13 @@ qemuDomainGetBlockIoTune(virDomainPtr dom,
             goto endjob;
         }
 
-        if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_MAX))
-            maxparams = QEMU_NB_BLOCK_IO_TUNE_PARAM;
-        else if (!virQEMUCapsGet(priv->qemuCaps,
-                                 QEMU_CAPS_DRIVE_IOTUNE_MAX_LENGTH))
-            maxparams = QEMU_NB_BLOCK_IO_TUNE_PARAM_MAX;
+        maxparams = QEMU_NB_BLOCK_IO_TUNE_BASE_PARAMS;
+        if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_MAX))
+            maxparams += QEMU_NB_BLOCK_IO_TUNE_MAX_PARAMS;
+        if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE_IOTUNE_MAX_LENGTH))
+            maxparams += QEMU_NB_BLOCK_IO_TUNE_LENGTH_PARAMS;
+    } else {
+        maxparams = QEMU_NB_BLOCK_IO_TUNE_ALL_PARAMS;
     }
 
     if (*nparams == 0) {
-- 
2.7.4