[PATCH v2 4/6] PCI/sysfs: Avoid runtime PM at config-space EOF

[Ziming Du]

pci_read_config() and pci_write_config() only reject offsets beyond the
end of configuration space. An offset exactly at the end is reduced to a
zero-length transfer after the bounds adjustment, but still takes and
drops a runtime PM reference despite doing no work.

Return immediately for offsets at the end of configuration space.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Suggested-by: Krzysztof Wilczyński <kw@xxxxxxxxx>
Signed-off-by: Ziming Du <duziming2@xxxxxxxxxx>
---
 drivers/pci/pci-sysfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 5ec0b245a69bd..a4f6559c619c7 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -718,7 +718,7 @@ static ssize_t pci_read_config(struct file *filp, struct kobject *kobj,
 	else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS)
 		size = 128;
 
-	if (off > size)
+	if (off >= size)
 		return 0;
 	if (off + count > size) {
 		size -= off;
@@ -799,7 +799,7 @@ static ssize_t pci_write_config(struct file *filp, struct kobject *kobj,
 		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
 	}
 
-	if (off > dev->cfg_size)
+	if (off >= dev->cfg_size)
 		return 0;
 	if (off + count > dev->cfg_size) {
 		size = dev->cfg_size - off;
-- 
2.43.0