netdev - [PATCH net-next v3] net: tulip: avoid unused variable warning

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Message-Id: <20250318-tulip-w1-v3-1-a813fadd164d@kernel.org>
Date: Tue, 18 Mar 2025 13:53:34 +0000
From: Simon Horman <horms@...nel.org>
To: 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>
Cc: Helge Deller <deller@....de>, netdev@...r.kernel.org, 
 linux-parisc@...r.kernel.org
Subject: [PATCH net-next v3] net: tulip: avoid unused variable warning

There is an effort to achieve W=1 kernel builds without warnings.
As part of that effort Helge Deller highlighted the following warnings
in the tulip driver when compiling with W=1 and CONFIG_TULIP_MWI=n:

  .../tulip_core.c: In function ‘tulip_init_one’:
  .../tulip_core.c:1309:22: warning: variable ‘force_csr0’ set but not used

This patch addresses that problem using IS_ENABLED(). This approach has
the added benefit of reducing conditionally compiled code. And thus
increasing compile coverage. E.g. for allmodconfig builds which enable
CONFIG_TULIP_MWI.

Compile tested only.
No run-time effect intended.

Acked-by: Helge Deller <deller@....de>
Signed-off-by: Simon Horman <horms@...nel.org>
---
Changes in v3:
- Fix mangled commit message
- Link to v2: https://lore.kernel.org/r/20250313-tulip-w1-v2-1-2ac0d3d909f9@kernel.org

Changes in v2:
- Use IS_ENABLED rather than __maybe_unused
- Link to v1: https://lore.kernel.org/netdev/20250309214238.66155-1-deller@kernel.org/

Note about v1:
- Original patch by Helge Deller
---
 drivers/net/ethernet/dec/tulip/tulip_core.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/dec/tulip/tulip_core.c b/drivers/net/ethernet/dec/tulip/tulip_core.c
index 27e01d780cd0..75eac18ff246 100644
--- a/drivers/net/ethernet/dec/tulip/tulip_core.c
+++ b/drivers/net/ethernet/dec/tulip/tulip_core.c
@@ -1177,7 +1177,6 @@ static void set_rx_mode(struct net_device *dev)
 	iowrite32(csr6, ioaddr + CSR6);
 }

-#ifdef CONFIG_TULIP_MWI
 static void tulip_mwi_config(struct pci_dev *pdev, struct net_device *dev)
 {
 	struct tulip_private *tp = netdev_priv(dev);
@@ -1251,7 +1250,6 @@ static void tulip_mwi_config(struct pci_dev *pdev, struct net_device *dev)
 		netdev_dbg(dev, "MWI config cacheline=%d, csr0=%08x\n",
 			   cache, csr0);
 }
-#endif

 /*
  *	Chips that have the MRM/reserved bit quirk and the burst quirk. That
@@ -1463,10 +1461,9 @@ static int tulip_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)

 	INIT_WORK(&tp->media_work, tulip_tbl[tp->chip_id].media_task);

-#ifdef CONFIG_TULIP_MWI
-	if (!force_csr0 && (tp->flags & HAS_PCI_MWI))
+	if (IS_ENABLED(CONFIG_TULIP_MWI) && !force_csr0 &&
+	    (tp->flags & HAS_PCI_MWI))
 		tulip_mwi_config (pdev, dev);
-#endif

 	/* Stop the chip's Tx and Rx processes. */
 	tulip_stop_rxtx(tp);