diff mbox series

ixgb: Remove useless DMA-32 fallback configuration

Message ID a56f72c090866c11a0c091e561dbfc69d826cd0e.1641748751.git.christophe.jaillet@wanadoo.fr (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series ixgb: Remove useless DMA-32 fallback configuration | expand

Checks

Context Check Description
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 38 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Christophe JAILLET Jan. 9, 2022, 5:19 p.m. UTC 
As stated in [1], dma_set_mask() with a 64-bit mask never fails if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

So, if dma_set_mask_and_coherent() succeeds, 'pci_using_dac' is known to be
1.

Simplify code and remove some dead code accordingly.

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

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
---
 drivers/net/ethernet/intel/ixgb/ixgb_main.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

Comments

Christoph Hellwig Jan. 10, 2022, 7:11 a.m. UTC | #1 
Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/ixgb/ixgb_main.c b/drivers/net/ethernet/intel/ixgb/ixgb_main.c
index 99d481904ce6..affdefcca7e3 100644
--- a/drivers/net/ethernet/intel/ixgb/ixgb_main.c
+++ b/drivers/net/ethernet/intel/ixgb/ixgb_main.c
@@ -361,7 +361,6 @@  ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	struct net_device *netdev = NULL;
 	struct ixgb_adapter *adapter;
 	static int cards_found = 0;
-	int pci_using_dac;
 	u8 addr[ETH_ALEN];
 	int i;
 	int err;
@@ -370,16 +369,10 @@  ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (err)
 		return err;
 
-	pci_using_dac = 0;
 	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
-	if (!err) {
-		pci_using_dac = 1;
-	} else {
-		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
-		if (err) {
-			pr_err("No usable DMA configuration, aborting\n");
-			goto err_dma_mask;
-		}
+	if (err) {
+		pr_err("No usable DMA configuration, aborting\n");
+		goto err_dma_mask;
 	}
 
 	err = pci_request_regions(pdev, ixgb_driver_name);
@@ -444,10 +437,8 @@  ixgb_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 			   NETIF_F_HW_VLAN_CTAG_FILTER;
 	netdev->hw_features |= NETIF_F_RXCSUM;
 
-	if (pci_using_dac) {
-		netdev->features |= NETIF_F_HIGHDMA;
-		netdev->vlan_features |= NETIF_F_HIGHDMA;
-	}
+	netdev->features |= NETIF_F_HIGHDMA;
+	netdev->vlan_features |= NETIF_F_HIGHDMA;
 
 	/* MTU range: 68 - 16114 */
 	netdev->min_mtu = ETH_MIN_MTU;