diff mbox series

[v3,2/2] hw/arm/smmu-common: Simplify smmu_find_smmu_pcibus() logic

Message ID 20200227164728.11635-3-philmd@redhat.com (mailing list archive)
State New, archived
Headers show
Series hw/arm/smmu-common: Avoid smmu_find_smmu_pcibus return dangling pointer | expand

Commit Message

Philippe Mathieu-Daudé Feb. 27, 2020, 4:47 p.m. UTC 
The smmu_find_smmu_pcibus() function was introduced (in commit
cac994ef43b) in a code format that could return an incorrect
pointer, which was then fixed by the previous commit.
We could have avoided this by writing the if() statement
differently. Do it now, in case this function is re-used.
The code is easier to review (harder to miss bugs).

Acked-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
This patch is easier to review with 'git-diff -w' (--ignore-all-space)

v3: Fixed typo reported by Eric
---
 hw/arm/smmu-common.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 67d7b2d0fd..e13a5f4a7c 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -290,20 +290,21 @@  inline int smmu_ptw(SMMUTransCfg *cfg, dma_addr_t iova, IOMMUAccessFlags perm,
 SMMUPciBus *smmu_find_smmu_pcibus(SMMUState *s, uint8_t bus_num)
 {
     SMMUPciBus *smmu_pci_bus = s->smmu_pcibus_by_bus_num[bus_num];
+    GHashTableIter iter;
 
-    if (!smmu_pci_bus) {
-        GHashTableIter iter;
-
-        g_hash_table_iter_init(&iter, s->smmu_pcibus_by_busptr);
-        while (g_hash_table_iter_next(&iter, NULL, (void **)&smmu_pci_bus)) {
-            if (pci_bus_num(smmu_pci_bus->bus) == bus_num) {
-                s->smmu_pcibus_by_bus_num[bus_num] = smmu_pci_bus;
-                return smmu_pci_bus;
-            }
-        }
-        smmu_pci_bus = NULL;
+    if (smmu_pci_bus) {
+        return smmu_pci_bus;
     }
-    return smmu_pci_bus;
+
+    g_hash_table_iter_init(&iter, s->smmu_pcibus_by_busptr);
+    while (g_hash_table_iter_next(&iter, NULL, (void **)&smmu_pci_bus)) {
+        if (pci_bus_num(smmu_pci_bus->bus) == bus_num) {
+            s->smmu_pcibus_by_bus_num[bus_num] = smmu_pci_bus;
+            return smmu_pci_bus;
+        }
+    }
+
+    return NULL;
 }
 
 static AddressSpace *smmu_find_add_as(PCIBus *bus, void *opaque, int devfn)