linux-kernel - Re: [PATCH 3/4] igb: drop checksum constant cast to u16 in comparisons

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Message-ID: <20250625122137.GD1562@horms.kernel.org>
Date: Wed, 25 Jun 2025 13:21:37 +0100
From: Simon Horman <horms@...nel.org>
To: Jacek Kowalski <jacek@...ekk.info>
Cc: Tony Nguyen <anthony.l.nguyen@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] igb: drop checksum constant cast to u16 in
 comparisons

On Tue, Jun 24, 2025 at 09:30:44PM +0200, Jacek Kowalski wrote:

As per my comment on patch 1/4, some text should go here.

> Signed-off-by: Jacek Kowalski <Jacek@...ekk.info>
> Suggested-by: Simon Horman <horms@...nel.org>
> ---
>  drivers/net/ethernet/intel/igb/e1000_82575.c | 2 +-
>  drivers/net/ethernet/intel/igb/e1000_nvm.c   | 2 +-

These changes look good to me, but I think we should also do:

diff --git a/drivers/net/ethernet/intel/igb/e1000_82575.c b/drivers/net/ethernet/intel/igb/e1000_82575.c
index 12ad1dc90169..44a85ad749a4 100644
--- a/drivers/net/ethernet/intel/igb/e1000_82575.c
+++ b/drivers/net/ethernet/intel/igb/e1000_82575.c
@@ -2406,7 +2406,7 @@ static s32 igb_update_nvm_checksum_with_offset(struct e1000_hw *hw, u16 offset)
 		}
 		checksum += nvm_data;
 	}
-	checksum = (u16) NVM_SUM - checksum;
+	checksum = NVM_SUM - checksum;
 	ret_val = hw->nvm.ops.write(hw, (NVM_CHECKSUM_REG + offset), 1,
 				&checksum);
 	if (ret_val)
diff --git a/drivers/net/ethernet/intel/igb/e1000_nvm.c b/drivers/net/ethernet/intel/igb/e1000_nvm.c
index e654310b1161..c8638502c2be 100644
--- a/drivers/net/ethernet/intel/igb/e1000_nvm.c
+++ b/drivers/net/ethernet/intel/igb/e1000_nvm.c
@@ -668,7 +668,7 @@ s32 igb_update_nvm_checksum(struct e1000_hw *hw)
 		}
 		checksum += nvm_data;
 	}
-	checksum = (u16) NVM_SUM - checksum;
+	checksum = NVM_SUM - checksum;
 	ret_val = hw->nvm.ops.write(hw, NVM_CHECKSUM_REG, 1, &checksum);
 	if (ret_val)
 		hw_dbg("NVM Write Error while updating checksum.\n");