2019-10-30 21:13:44

by Christoph Hellwig

[permalink] [raw]
Subject: ioc3_eth DMA API fixes

Hi Dave and Thomas,

please take a look at this series which fixes DMA API usage in the ioc3
ethernet driver. At least the first one is a nasty abuse of internal
APIs introduced in 5.4-rc which I'd prefer to be fixed before 5.4 final.


2019-10-30 21:13:48

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

dma_direct_ is a low-level API that must never be used by drivers
directly. Switch to use the proper DMA API instead.

Fixes: ed870f6a7aa2 ("net: sgi: ioc3-eth: use dma-direct for dma allocations")
Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/net/ethernet/sgi/ioc3-eth.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/sgi/ioc3-eth.c b/drivers/net/ethernet/sgi/ioc3-eth.c
index deb636d653f3..477af82bf8a9 100644
--- a/drivers/net/ethernet/sgi/ioc3-eth.c
+++ b/drivers/net/ethernet/sgi/ioc3-eth.c
@@ -48,7 +48,7 @@
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/skbuff.h>
-#include <linux/dma-direct.h>
+#include <linux/dma-mapping.h>

#include <net/ip.h>

@@ -1242,8 +1242,8 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
ioc3_stop(ip);

/* Allocate rx ring. 4kb = 512 entries, must be 4kb aligned */
- ip->rxr = dma_direct_alloc_pages(ip->dma_dev, RX_RING_SIZE,
- &ip->rxr_dma, GFP_ATOMIC, 0);
+ ip->rxr = dma_alloc_coherent(ip->dma_dev, RX_RING_SIZE, &ip->rxr_dma,
+ GFP_ATOMIC);
if (!ip->rxr) {
pr_err("ioc3-eth: rx ring allocation failed\n");
err = -ENOMEM;
@@ -1251,9 +1251,8 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
}

/* Allocate tx rings. 16kb = 128 bufs, must be 16kb aligned */
- ip->txr = dma_direct_alloc_pages(ip->dma_dev, TX_RING_SIZE,
- &ip->txr_dma,
- GFP_KERNEL | __GFP_ZERO, 0);
+ ip->txr = dma_alloc_coherent(ip->dma_dev, TX_RING_SIZE, &ip->txr_dma,
+ GFP_KERNEL | __GFP_ZERO);
if (!ip->txr) {
pr_err("ioc3-eth: tx ring allocation failed\n");
err = -ENOMEM;
@@ -1313,11 +1312,11 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
out_stop:
del_timer_sync(&ip->ioc3_timer);
if (ip->rxr)
- dma_direct_free_pages(ip->dma_dev, RX_RING_SIZE, ip->rxr,
- ip->rxr_dma, 0);
+ dma_free_coherent(ip->dma_dev, RX_RING_SIZE, ip->rxr,
+ ip->rxr_dma);
if (ip->txr)
- dma_direct_free_pages(ip->dma_dev, TX_RING_SIZE, ip->txr,
- ip->txr_dma, 0);
+ dma_free_coherent(ip->dma_dev, TX_RING_SIZE, ip->txr,
+ ip->txr_dma);
out_res:
pci_release_regions(pdev);
out_free:
@@ -1335,10 +1334,8 @@ static void ioc3_remove_one(struct pci_dev *pdev)
struct net_device *dev = pci_get_drvdata(pdev);
struct ioc3_private *ip = netdev_priv(dev);

- dma_direct_free_pages(ip->dma_dev, RX_RING_SIZE, ip->rxr,
- ip->rxr_dma, 0);
- dma_direct_free_pages(ip->dma_dev, TX_RING_SIZE, ip->txr,
- ip->txr_dma, 0);
+ dma_free_coherent(ip->dma_dev, RX_RING_SIZE, ip->rxr, ip->rxr_dma);
+ dma_free_coherent(ip->dma_dev, TX_RING_SIZE, ip->txr, ip->txr_dma);

unregister_netdev(dev);
del_timer_sync(&ip->ioc3_timer);
--
2.20.1

2019-10-30 21:14:00

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 2/4] net: sgi: ioc3-eth: fix usage of GFP_* flags

dma_alloc_coherent always zeroes memory, there is no need for
__GFP_ZERO. Also doing a GFP_ATOMIC allocation just before a GFP_KERNEL
one is clearly bogus.

Fixes: ed870f6a7aa2 ("net: sgi: ioc3-eth: use dma-direct for dma allocations")
Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/net/ethernet/sgi/ioc3-eth.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sgi/ioc3-eth.c b/drivers/net/ethernet/sgi/ioc3-eth.c
index 477af82bf8a9..8a684d882e63 100644
--- a/drivers/net/ethernet/sgi/ioc3-eth.c
+++ b/drivers/net/ethernet/sgi/ioc3-eth.c
@@ -1243,7 +1243,7 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

/* Allocate rx ring. 4kb = 512 entries, must be 4kb aligned */
ip->rxr = dma_alloc_coherent(ip->dma_dev, RX_RING_SIZE, &ip->rxr_dma,
- GFP_ATOMIC);
+ GFP_KERNEL);
if (!ip->rxr) {
pr_err("ioc3-eth: rx ring allocation failed\n");
err = -ENOMEM;
@@ -1252,7 +1252,7 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)

/* Allocate tx rings. 16kb = 128 bufs, must be 16kb aligned */
ip->txr = dma_alloc_coherent(ip->dma_dev, TX_RING_SIZE, &ip->txr_dma,
- GFP_KERNEL | __GFP_ZERO);
+ GFP_KERNEL);
if (!ip->txr) {
pr_err("ioc3-eth: tx ring allocation failed\n");
err = -ENOMEM;
--
2.20.1

2019-10-30 21:15:45

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 4/4] net: sgi: ioc3-eth: fix setting NETIF_F_HIGHDMA

Set NETIF_F_HIGHDMA together with the NETIF_F_IP_CSUM flag insted of
letting the second assignment overwrite it. Probably doesn't matter
in practice as none of the systems a IOC3 is usually found in has
highmem to start with.

Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/net/ethernet/sgi/ioc3-eth.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/sgi/ioc3-eth.c b/drivers/net/ethernet/sgi/ioc3-eth.c
index dc2e22652b55..1af68826810a 100644
--- a/drivers/net/ethernet/sgi/ioc3-eth.c
+++ b/drivers/net/ethernet/sgi/ioc3-eth.c
@@ -1192,8 +1192,6 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto out_disable;
}

- dev->features |= NETIF_F_HIGHDMA;
-
err = pci_request_regions(pdev, "ioc3");
if (err)
goto out_free;
@@ -1274,7 +1272,7 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
dev->netdev_ops = &ioc3_netdev_ops;
dev->ethtool_ops = &ioc3_ethtool_ops;
dev->hw_features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM;
- dev->features = NETIF_F_IP_CSUM;
+ dev->features = NETIF_F_IP_CSUM | NETIF_F_HIGHDMA;

sw_physid1 = ioc3_mdio_read(dev, ip->mii.phy_id, MII_PHYSID1);
sw_physid2 = ioc3_mdio_read(dev, ip->mii.phy_id, MII_PHYSID2);
--
2.20.1

2019-10-30 21:17:05

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 3/4] net: sgi: ioc3-eth: simplify setting the DMA mask

There is no need to fall back to a lower mask these days, the DMA mask
just communictes the hardware supported features.

Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/net/ethernet/sgi/ioc3-eth.c | 27 +++++++--------------------
1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/sgi/ioc3-eth.c b/drivers/net/ethernet/sgi/ioc3-eth.c
index 8a684d882e63..dc2e22652b55 100644
--- a/drivers/net/ethernet/sgi/ioc3-eth.c
+++ b/drivers/net/ethernet/sgi/ioc3-eth.c
@@ -1173,26 +1173,14 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
struct ioc3 *ioc3;
unsigned long ioc3_base, ioc3_size;
u32 vendor, model, rev;
- int err, pci_using_dac;
+ int err;

/* Configure DMA attributes. */
- err = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
- if (!err) {
- pci_using_dac = 1;
- err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
- if (err < 0) {
- pr_err("%s: Unable to obtain 64 bit DMA for consistent allocations\n",
- pci_name(pdev));
- goto out;
- }
- } else {
- err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
- if (err) {
- pr_err("%s: No usable DMA configuration, aborting.\n",
- pci_name(pdev));
- goto out;
- }
- pci_using_dac = 0;
+ err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+ if (err) {
+ pr_err("%s: No usable DMA configuration, aborting.\n",
+ pci_name(pdev));
+ goto out;
}

if (pci_enable_device(pdev))
@@ -1204,8 +1192,7 @@ static int ioc3_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
goto out_disable;
}

- if (pci_using_dac)
- dev->features |= NETIF_F_HIGHDMA;
+ dev->features |= NETIF_F_HIGHDMA;

err = pci_request_regions(pdev, "ioc3");
if (err)
--
2.20.1

2019-10-30 22:07:19

by Thomas Bogendoerfer

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

On Wed, 30 Oct 2019 14:12:30 -0700
Christoph Hellwig <[email protected]> wrote:

> dma_direct_ is a low-level API that must never be used by drivers
> directly. Switch to use the proper DMA API instead.

is the 4kb/16kb alignment still guaranteed ? If not how is the way
to get such an alignment ?

Thomas.

--
SUSE Software Solutions Germany GmbH
HRB 36809 (AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

2019-10-30 22:39:32

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

On Wed, Oct 30, 2019 at 11:05:49PM +0100, Thomas Bogendoerfer wrote:
> On Wed, 30 Oct 2019 14:12:30 -0700
> Christoph Hellwig <[email protected]> wrote:
>
> > dma_direct_ is a low-level API that must never be used by drivers
> > directly. Switch to use the proper DMA API instead.
>
> is the 4kb/16kb alignment still guaranteed ? If not how is the way
> to get such an alignment ?

The DMA API gives you page aligned memory. dma_direct doesn't give you
any gurantees as it is an internal API explicitly documented as not
for driver usage that can change at any time.

2019-10-31 08:57:09

by Thomas Bogendoerfer

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

On Wed, 30 Oct 2019 23:38:18 +0100
Christoph Hellwig <[email protected]> wrote:

> On Wed, Oct 30, 2019 at 11:05:49PM +0100, Thomas Bogendoerfer wrote:
> > On Wed, 30 Oct 2019 14:12:30 -0700
> > Christoph Hellwig <[email protected]> wrote:
> >
> > > dma_direct_ is a low-level API that must never be used by drivers
> > > directly. Switch to use the proper DMA API instead.
> >
> > is the 4kb/16kb alignment still guaranteed ? If not how is the way
> > to get such an alignment ?
>
> The DMA API gives you page aligned memory. dma_direct doesn't give you
> any gurantees as it is an internal API explicitly documented as not
> for driver usage that can change at any time.

I didn't want to argue about that. What I'm interested in is a way how
to allocate dma memory, which is 16kB aligned, via the DMA API ?

Thomas.

--
SUSE Software Solutions Germany GmbH
HRB 36809 (AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

2019-10-31 13:16:13

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

On Thu, Oct 31, 2019 at 09:54:30AM +0100, Thomas Bogendoerfer wrote:
> I didn't want to argue about that. What I'm interested in is a way how
> to allocate dma memory, which is 16kB aligned, via the DMA API ?

You can't.

2019-10-31 15:20:14

by Thomas Bogendoerfer

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

On Thu, 31 Oct 2019 14:15:01 +0100
Christoph Hellwig <[email protected]> wrote:

> On Thu, Oct 31, 2019 at 09:54:30AM +0100, Thomas Bogendoerfer wrote:
> > I didn't want to argue about that. What I'm interested in is a way how
> > to allocate dma memory, which is 16kB aligned, via the DMA API ?
>
> You can't.

So then __get_free_pages() and dma_map_page() is the only way ?

BTW I've successful tested your patches on an 8 CPU Origin 2k.

Thomas.

--
SUSE Software Solutions Germany GmbH
HRB 36809 (AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

2019-10-31 17:06:04

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

On Thu, Oct 31, 2019 at 04:18:17PM +0100, Thomas Bogendoerfer wrote:
> On Thu, 31 Oct 2019 14:15:01 +0100
> Christoph Hellwig <[email protected]> wrote:
>
> > On Thu, Oct 31, 2019 at 09:54:30AM +0100, Thomas Bogendoerfer wrote:
> > > I didn't want to argue about that. What I'm interested in is a way how
> > > to allocate dma memory, which is 16kB aligned, via the DMA API ?
> >
> > You can't.
>
> So then __get_free_pages() and dma_map_page() is the only way ?

Or dma_alloc_coherent + check alignment + allocate larger and align
yourself. In practice you'll always get alignmened memory at the
moment, but there is no API gurantee.

2019-10-31 22:17:59

by David Miller

[permalink] [raw]
Subject: Re: [PATCH 1/4] net: sgi: ioc3-eth: don't abuse dma_direct_* calls

From: Thomas Bogendoerfer <[email protected]>
Date: Thu, 31 Oct 2019 16:18:17 +0100

> On Thu, 31 Oct 2019 14:15:01 +0100
> Christoph Hellwig <[email protected]> wrote:
>
>> On Thu, Oct 31, 2019 at 09:54:30AM +0100, Thomas Bogendoerfer wrote:
>> > I didn't want to argue about that. What I'm interested in is a way how
>> > to allocate dma memory, which is 16kB aligned, via the DMA API ?
>>
>> You can't.
>
> So then __get_free_pages() and dma_map_page() is the only way ?
>
> BTW I've successful tested your patches on an 8 CPU Origin 2k.

Nope, it is not the only way.

Allocate a (SIZE*2)-1 sized piece of DMA memory and align the
resulting CPU pointer and DMA address as needed.

2019-10-31 22:52:36

by David Miller

[permalink] [raw]
Subject: Re: ioc3_eth DMA API fixes

From: Christoph Hellwig <[email protected]>
Date: Wed, 30 Oct 2019 14:12:29 -0700

> Hi Dave and Thomas,
>
> please take a look at this series which fixes DMA API usage in the ioc3
> ethernet driver. At least the first one is a nasty abuse of internal
> APIs introduced in 5.4-rc which I'd prefer to be fixed before 5.4 final.

Please add the alignment code for 16K or whatever they need and I'll apply
this series.

Thanks.

2019-10-31 22:53:11

by Christoph Hellwig

[permalink] [raw]
Subject: Re: ioc3_eth DMA API fixes

On Thu, Oct 31, 2019 at 02:13:34PM -0700, David Miller wrote:
> From: Christoph Hellwig <[email protected]>
> Date: Wed, 30 Oct 2019 14:12:29 -0700
>
> > Hi Dave and Thomas,
> >
> > please take a look at this series which fixes DMA API usage in the ioc3
> > ethernet driver. At least the first one is a nasty abuse of internal
> > APIs introduced in 5.4-rc which I'd prefer to be fixed before 5.4 final.
>
> Please add the alignment code for 16K or whatever they need and I'll apply
> this series.

I'll let Thomas add this as this series doesn't change anything in that
regard.