linux-kernel - [PATCH] net: alteon: Simplify DMA setting

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Date:   Sat,  8 Jan 2022 15:26:06 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     jes@...ined-monkey.org, davem@...emloft.net, kuba@...nel.org
Cc:     linux-acenic@...site.dk, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] net: alteon: Simplify DMA setting

As stated in [1], dma_set_mask() with a 64-bit mask will never fail if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

If dma_set_mask_and_coherent() succeeds, 'ap->pci_using_dac' is known to be
1. So 'pci_using_dac' can be removed from the 'struct ace_private'.

Simplify code and remove some dead code accordingly.


[1]: https://lkml.org/lkml/2021/6/7/398

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/net/ethernet/alteon/acenic.c | 9 ++-------
 drivers/net/ethernet/alteon/acenic.h | 1 -
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/alteon/acenic.c b/drivers/net/ethernet/alteon/acenic.c
index 732da15a3827..22fe98555b24 100644
--- a/drivers/net/ethernet/alteon/acenic.c
+++ b/drivers/net/ethernet/alteon/acenic.c
@@ -589,8 +589,7 @@ static int acenic_probe_one(struct pci_dev *pdev,
 	}
 	ap->name = dev->name;
 
-	if (ap->pci_using_dac)
-		dev->features |= NETIF_F_HIGHDMA;
+	dev->features |= NETIF_F_HIGHDMA;
 
 	pci_set_drvdata(pdev, dev);
 
@@ -1130,11 +1129,7 @@ static int ace_init(struct net_device *dev)
 	/*
 	 * Configure DMA attributes.
 	 */
-	if (!dma_set_mask(&pdev->dev, DMA_BIT_MASK(64))) {
-		ap->pci_using_dac = 1;
-	} else if (!dma_set_mask(&pdev->dev, DMA_BIT_MASK(32))) {
-		ap->pci_using_dac = 0;
-	} else {
+	if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(64))) {
 		ecode = -ENODEV;
 		goto init_error;
 	}
diff --git a/drivers/net/ethernet/alteon/acenic.h b/drivers/net/ethernet/alteon/acenic.h
index 265fa601a258..ca5ce0cbbad1 100644
--- a/drivers/net/ethernet/alteon/acenic.h
+++ b/drivers/net/ethernet/alteon/acenic.h
@@ -692,7 +692,6 @@ struct ace_private
 				__attribute__ ((aligned (SMP_CACHE_BYTES)));
 	u32			last_tx, last_std_rx, last_mini_rx;
 #endif
-	int			pci_using_dac;
 	u8			firmware_major;
 	u8			firmware_minor;
 	u8			firmware_fix;
-- 
2.32.0