* [PATCH] ixgb: Remove useless DMA-32 fallback configuration
@ 2022-01-09 17:19 ` Christophe JAILLET
0 siblings, 0 replies; 4+ messages in thread
From: Christophe JAILLET @ 2022-01-09 17:19 UTC (permalink / raw)
To: Jesse Brandeburg, Tony Nguyen, David S. Miller, Jakub Kicinski
Cc: linux-kernel, kernel-janitors, Christophe JAILLET,
Christoph Hellwig, Alexander Lobakin, intel-wired-lan, netdev
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(-)
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;
--
2.32.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Intel-wired-lan] [PATCH] ixgb: Remove useless DMA-32 fallback configuration
@ 2022-01-09 17:19 ` Christophe JAILLET
0 siblings, 0 replies; 4+ messages in thread
From: Christophe JAILLET @ 2022-01-09 17:19 UTC (permalink / raw)
To: intel-wired-lan
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(-)
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;
--
2.32.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ixgb: Remove useless DMA-32 fallback configuration
2022-01-09 17:19 ` [Intel-wired-lan] " Christophe JAILLET
@ 2022-01-10 7:11 ` Christoph Hellwig
-1 siblings, 0 replies; 4+ messages in thread
From: Christoph Hellwig @ 2022-01-10 7:11 UTC (permalink / raw)
To: Christophe JAILLET
Cc: Jesse Brandeburg, Tony Nguyen, David S. Miller, Jakub Kicinski,
linux-kernel, kernel-janitors, Christoph Hellwig,
Alexander Lobakin, intel-wired-lan, netdev
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Intel-wired-lan] [PATCH] ixgb: Remove useless DMA-32 fallback configuration
@ 2022-01-10 7:11 ` Christoph Hellwig
0 siblings, 0 replies; 4+ messages in thread
From: Christoph Hellwig @ 2022-01-10 7:11 UTC (permalink / raw)
To: intel-wired-lan
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-01-10 7:11 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-01-09 17:19 [PATCH] ixgb: Remove useless DMA-32 fallback configuration Christophe JAILLET
2022-01-09 17:19 ` [Intel-wired-lan] " Christophe JAILLET
2022-01-10 7:11 ` Christoph Hellwig
2022-01-10 7:11 ` [Intel-wired-lan] " Christoph Hellwig
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