Avoid zero size allocation in cache_k8_northbridges()

kmalloc for flush_words resulted in zero size allocation when no
k8_northbridges existed.  Short circuit the code path for this case.

Also remove uneeded zeroing of num_k8_northbridges just after checking if
it is zero.

Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86_64/kernel/k8.c b/arch/x86_64/kernel/k8.c
index bc11b32..7377ccb 100644 (file)
--- a/arch/x86_64/kernel/k8.c
+++ b/arch/x86_64/kernel/k8.c
@@ -39,10 +39,10 @@ int cache_k8_northbridges(void)
 {
        int i;
        struct pci_dev *dev;
+
        if (num_k8_northbridges)
                return 0;
 
-       num_k8_northbridges = 0;
        dev = NULL;
        while ((dev = next_k8_northbridge(dev)) != NULL)
                num_k8_northbridges++;
@@ -52,6 +52,11 @@ int cache_k8_northbridges(void)
        if (!k8_northbridges)
                return -ENOMEM;
 
+       if (!num_k8_northbridges) {
+               k8_northbridges[0] = NULL;
+               return 0;
+       }
+
        flush_words = kmalloc(num_k8_northbridges * sizeof(u32), GFP_KERNEL);
        if (!flush_words) {
                kfree(k8_northbridges);