pci_resource_end() can be 0 only when pci_resource_start() is 0.
Otherwise, it is definitely an error. In this case, pci_resource_len()
should be regarded as 0. Therefore, determining whether
pci_resource_start() and pci_resource_end() are both 0 can be reduced to
determining only whether pci_resource_end() is 0.
Although only one condition judgment is reduced, the macro function
pci_resource_len() is widely referenced in the kernel. I used defconfig to
compile the latest kernel on X86, and its binary code size was reduced by
about 3KB.
Before:
[ 2] .rela.text RELA 0000000000000000 093bfcb0
0000000001a67168 0000000000000018 I 68 1 8
After:
[ 2] .rela.text RELA 0000000000000000 093bfcb0
0000000001a66598 0000000000000018 I 68 1 8
Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
include/linux/pci.h | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 540b377ca8f6..23ef1a15eb5d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1881,9 +1881,7 @@ int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma);
#define pci_resource_end(dev, bar) ((dev)->resource[(bar)].end)
#define pci_resource_flags(dev, bar) ((dev)->resource[(bar)].flags)
#define pci_resource_len(dev,bar) \
- ((pci_resource_start((dev), (bar)) == 0 && \
- pci_resource_end((dev), (bar)) == \
- pci_resource_start((dev), (bar))) ? 0 : \
+ ((pci_resource_end((dev), (bar)) == 0) ? 0 : \
\
(pci_resource_end((dev), (bar)) - \
pci_resource_start((dev), (bar)) + 1))
--
2.25.1
