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

On Sun, 23 Aug 2026 10:52:12 +0300
Sergey Shtylyov [off-list ref] wrote:

On 8/22/26 11:21 PM, Sergey Shtylyov wrote:

quoted

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>  

   Actually, scratch this patch -- it's not entirely correct... :-/

[...]> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c

quoted

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;
 	}
   

   I forgot to check size for 0 here...

I don't think it can be zero - assuming it isn't zero on entry.

David

quoted

+	ret = get_registers(tp, index, type, size, data);
+
+error1:
 	if (ret == -ENODEV)
 		rtl_set_unplug(tp);
 

@@ -1498,31 +1490,24 @@ static int generic_ocp_write(struct r8152 *tp, u16 index, u16 byteen,
 		if (byen != BYTE_EN_DWORD)
 			size -= 4;
 
-		while (size) {
-			if (size > limit) {
-				ret = set_registers(tp, index,
-						    type | BYTE_EN_DWORD,
-						    limit, data);
-				if (ret < 0)
-					goto error1;
-
-				index += limit;
-				data += limit;
-				size -= limit;
-			} else {
-				ret = set_registers(tp, index,
-						    type | BYTE_EN_DWORD,
-						    size, data);
-				if (ret < 0)
-					goto error1;
-
-				index += size;
-				data += size;
-				size = 0;
-				break;
-			}
+		while (size > limit) {
+			ret = set_registers(tp, index, type | BYTE_EN_DWORD,
+					    limit, data);
+			if (ret < 0)
+				goto error1;
+
+			index += limit;
+			data += limit;
+			size -= limit;
 		}
   

   And here...

quoted

+		ret = set_registers(tp, index, type | BYTE_EN_DWORD, size, data);
+		if (ret < 0)
+			goto error1;
+
+		index += size;
+		data += size;
+
 		/* Set the last DWORD */
 		if (byen != BYTE_EN_DWORD)
 			ret = set_registers(tp, index, type | byen, 4, data);  

MBR, Sergey