linux-kernel - [PATCH net-next 4/6] net: ipa: don't reuse variable names

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Date:   Fri,  9 Sep 2022 20:11:29 -0500
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com
Cc:     mka@...omium.org, evgreen@...omium.org, andersson@...nel.org,
        quic_cpratapa@...cinc.com, quic_avuyyuru@...cinc.com,
        quic_jponduru@...cinc.com, quic_subashab@...cinc.com,
        elder@...nel.org, netdev@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next 4/6] net: ipa: don't reuse variable names

In ipa_endpoint_init_hdr(), as well as ipa_endpoint_init_hdr_ext(),
a top-level automatic variable named "offset" is used to represent
the offset of a register.

However, deeper within each of those functions is *another*
definition of a local variable with the same name, representing
something else.  Scoping rules ensure the result is what was
intended, but this variable name reuse is bad practice and makes
the code confusing.

Fix this by naming the inner variable "off".  Use "off" instead of
"checksum_offset" in ipa_endpoint_init_cfg() for consistency.

Signed-off-by: Alex Elder <elder@...aro.org>
---
 drivers/net/ipa/ipa_endpoint.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 66d2bfdf9e423..eb68ce47698d0 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -494,12 +494,12 @@ static void ipa_endpoint_init_cfg(struct ipa_endpoint *endpoint)
 		enum ipa_version version = endpoint->ipa->version;
 
 		if (endpoint->toward_ipa) {
-			u32 checksum_offset;
+			u32 off;
 
 			/* Checksum header offset is in 4-byte units */
-			checksum_offset = sizeof(struct rmnet_map_header);
-			checksum_offset /= sizeof(u32);
-			val |= u32_encode_bits(checksum_offset,
+			off = sizeof(struct rmnet_map_header);
+			off /= sizeof(u32);
+			val |= u32_encode_bits(off,
 					       CS_METADATA_HDR_OFFSET_FMASK);
 
 			enabled = version < IPA_VERSION_4_5
@@ -590,20 +590,20 @@ static void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint)
 
 		/* Define how to fill fields in a received QMAP header */
 		if (!endpoint->toward_ipa) {
-			u32 offset;	/* Field offset within header */
+			u32 off;	/* Field offset within header */
 
 			/* Where IPA will write the metadata value */
-			offset = offsetof(struct rmnet_map_header, mux_id);
-			val |= ipa_metadata_offset_encoded(version, offset);
+			off = offsetof(struct rmnet_map_header, mux_id);
+			val |= ipa_metadata_offset_encoded(version, off);
 
 			/* Where IPA will write the length */
-			offset = offsetof(struct rmnet_map_header, pkt_len);
+			off = offsetof(struct rmnet_map_header, pkt_len);
 			/* Upper bits are stored in HDR_EXT with IPA v4.5 */
 			if (version >= IPA_VERSION_4_5)
-				offset &= field_mask(HDR_OFST_PKT_SIZE_FMASK);
+				off &= field_mask(HDR_OFST_PKT_SIZE_FMASK);
 
 			val |= HDR_OFST_PKT_SIZE_VALID_FMASK;
-			val |= u32_encode_bits(offset, HDR_OFST_PKT_SIZE_FMASK);
+			val |= u32_encode_bits(off, HDR_OFST_PKT_SIZE_FMASK);
 		}
 		/* For QMAP TX, metadata offset is 0 (modem assumes this) */
 		val |= HDR_OFST_METADATA_VALID_FMASK;
@@ -653,11 +653,11 @@ static void ipa_endpoint_init_hdr_ext(struct ipa_endpoint *endpoint)
 	if (ipa->version >= IPA_VERSION_4_5) {
 		/* HDR_TOTAL_LEN_OR_PAD_OFFSET is 0, so MSB is 0 */
 		if (endpoint->config.qmap && !endpoint->toward_ipa) {
-			u32 offset;
+			u32 off;
 
-			offset = offsetof(struct rmnet_map_header, pkt_len);
-			offset >>= hweight32(HDR_OFST_PKT_SIZE_FMASK);
-			val |= u32_encode_bits(offset,
+			off = offsetof(struct rmnet_map_header, pkt_len);
+			off >>= hweight32(HDR_OFST_PKT_SIZE_FMASK);
+			val |= u32_encode_bits(off,
 					       HDR_OFST_PKT_SIZE_MSB_FMASK);
 			/* HDR_ADDITIONAL_CONST_LEN is 0 so MSB is 0 */
 		}
-- 
2.34.1