Re: [PATCH 1/1] pseries/hotplug-memory.c: Change rc variable to bool

On 02.08.19 09:18, David Hildenbrand wrote:

On 02.08.19 01:10, Leonardo Bras wrote:

quoted

Changes the return variable to bool (as the return value) and
avoids doing a ternary operation before returning.

Also, since rc will always be true, there is no need to do
rc &= bool, as (true && X) will result in X.

Signed-off-by: Leonardo Bras <redacted>
---
 arch/powerpc/platforms/pseries/hotplug-memory.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 8e700390f3d6..392deb4855e5 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c

@@ -338,7 +338,7 @@ static int pseries_remove_mem_node(struct device_node *np)
 static bool lmb_is_removable(struct drmem_lmb *lmb)
 {
 	int i, scns_per_block;
-	int rc = 1;
+	bool rc = true;
 	unsigned long pfn, block_sz;
 	u64 phys_addr;
 

@@ -363,11 +363,11 @@ static bool lmb_is_removable(struct drmem_lmb *lmb)
 		if (!pfn_present(pfn))
 			continue;
 
-		rc &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
+		rc = is_mem_section_removable(pfn, PAGES_PER_SECTION);

No, that's wrong.

If is_mem_section_removable() is false in the first iteration but true
in the last iteration, you would return true instead of false, which
introduced a bug. We have to AND all sub-results, not simply use the
last one.

BTW, including such subtle changes in a "Change rc variable to bool"
patch should be avoided.

-- 

Thanks,

David / dhildenb