Thread (13 messages) flat view 13 messages, 4 authors, 12d ago

Re: [PATCH] r8152: simplify loops in generic_ocp_{read,write}()

From: Michal Pecio <hidden>
Date: 2026-08-22 21:03:34
Also in: linux-usb

On Sat, 22 Aug 2026 23:21:54 +0300, Sergey Shtylyov wrote:
quoted hunk ↗ jump to hunk
In generic_ocp_{read,write}(), the *while* loops look very strange:
the last iteration is executed differently to the prior ones, doing
some useless assignments before *break*. Move the code for the last
iteration out of the loop bodies, dropping the pointless statements
as well...

Found by Linux Verification Center (linuxtesting.org) with the Svace
static analysis tool.

Signed-off-by: Sergey Shtylyov <redacted>

---
 drivers/net/usb/r8152.c | 67 ++++++++++++++++-------------------------
 1 file changed, 26 insertions(+), 41 deletions(-)
diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index f61686433031..de9738bdce85 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -1431,27 +1431,19 @@ static int generic_ocp_read(struct r8152 *tp, u16 index, u16 size,
 	if ((u32)index + (u32)size > 0xffff)
 		return -EPERM;
 
-	while (size) {
-		if (size > limit) {
-			ret = get_registers(tp, index, type, limit, data);
-			if (ret < 0)
-				break;
-
-			index += limit;
-			data += limit;
-			size -= limit;
-		} else {
-			ret = get_registers(tp, index, type, size, data);
-			if (ret < 0)
-				break;
+	while (size > limit) {
+		ret = get_registers(tp, index, type, limit, data);
+		if (ret < 0)
+			goto error1;
 
-			index += size;
-			data += size;
-			size = 0;
-			break;
-		}
+		index += limit;
+		data += limit;
+		size -= limit;
 	}
 
+	ret = get_registers(tp, index, type, size, data);
+
+error1:
 	if (ret == -ENODEV)
 		rtl_set_unplug(tp);
Looks like it could be shorter still.

s/limit/chunk/

while (size) {
	if (size < chunk)
		chunk = size;
	ret = get_registers(tp, index, type, chunk, data);
	if (ret < 0)
		break;
	index += chunk;
	data += chunk;
	size -= chunk;
}

Then it could be do-while, because we know size > 0, though
I suppose compilers may figure it out themselves anyway.

Regards,
Michal
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help