* [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null
@ 2022-08-18 18:29 Sergei Antonov
2022-08-18 18:29 ` [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas Sergei Antonov
2022-08-18 19:18 ` [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Andrew Lunn
0 siblings, 2 replies; 7+ messages in thread
From: Sergei Antonov @ 2022-08-18 18:29 UTC (permalink / raw)
To: netdev; +Cc: Andrew Lunn, Jakub Kicinski, Vladimir Oltean, Sergei Antonov
It fixes a warning during error unwinding:
WARNING: CPU: 0 PID: 1 at kernel/dma/debug.c:963 check_unmap+0x704/0x980
DMA-API: moxart-ethernet 92000000.mac: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=1600 bytes]
CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0+ #60
Hardware name: Generic DT based system
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x34/0x44
dump_stack_lvl from __warn+0xbc/0x1f0
__warn from warn_slowpath_fmt+0x94/0xc8
warn_slowpath_fmt from check_unmap+0x704/0x980
check_unmap from debug_dma_unmap_page+0x8c/0x9c
debug_dma_unmap_page from moxart_mac_free_memory+0x3c/0xa8
moxart_mac_free_memory from moxart_mac_probe+0x190/0x218
moxart_mac_probe from platform_probe+0x48/0x88
platform_probe from really_probe+0xc0/0x2e4
Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver")
Signed-off-by: Sergei Antonov <saproj@gmail.com>
---
drivers/net/ethernet/moxa/moxart_ether.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index f11f1cb92025..edd1dab2ec43 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -77,8 +77,9 @@ static void moxart_mac_free_memory(struct net_device *ndev)
int i;
for (i = 0; i < RX_DESC_NUM; i++)
- dma_unmap_single(&priv->pdev->dev, priv->rx_mapping[i],
- priv->rx_buf_size, DMA_FROM_DEVICE);
+ if (priv->rx_mapping[i])
+ dma_unmap_single(&priv->pdev->dev, priv->rx_mapping[i],
+ priv->rx_buf_size, DMA_FROM_DEVICE);
if (priv->tx_desc_base)
dma_free_coherent(&priv->pdev->dev,
--
2.32.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas
2022-08-18 18:29 [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Sergei Antonov
@ 2022-08-18 18:29 ` Sergei Antonov
2022-08-18 19:27 ` Andrew Lunn
2022-08-18 19:18 ` [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Andrew Lunn
1 sibling, 1 reply; 7+ messages in thread
From: Sergei Antonov @ 2022-08-18 18:29 UTC (permalink / raw)
To: netdev; +Cc: Andrew Lunn, Jakub Kicinski, Vladimir Oltean, Sergei Antonov
Fix the warning poping up after bringing the link down, then up:
ip link set dev eth0 down
ip link set dev eth0 up
WARNING: CPU: 0 PID: 55 at kernel/dma/debug.c:570 add_dma_entry+0x204/0x2ec
DMA-API: moxart-ethernet 92000000.mac: cacheline tracking EEXIST, overlapping mappings aren't supported
CPU: 0 PID: 55 Comm: ip Not tainted 5.19.0+ #57
Hardware name: Generic DT based system
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x34/0x44
dump_stack_lvl from __warn+0xbc/0x1f0
__warn from warn_slowpath_fmt+0x94/0xc8
warn_slowpath_fmt from add_dma_entry+0x204/0x2ec
add_dma_entry from dma_map_page_attrs+0x110/0x328
dma_map_page_attrs from moxart_mac_open+0x134/0x320
moxart_mac_open from __dev_open+0x11c/0x1ec
__dev_open from __dev_change_flags+0x194/0x22c
__dev_change_flags from dev_change_flags+0x14/0x44
dev_change_flags from devinet_ioctl+0x6d4/0x93c
devinet_ioctl from inet_ioctl+0x1ac/0x25c
Unmap RX memory areas in moxart_mac_stop(), so that moxart_mac_open()
will map them anew instead of double-mapping. To avoid code duplication,
create a new function moxart_mac_unmap_rx(). Nullify unmapped pointers to
prevent double-unmapping (ex: moxart_mac_stop(), then moxart_remove()).
Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver")
Signed-off-by: Sergei Antonov <saproj@gmail.com>
---
drivers/net/ethernet/moxa/moxart_ether.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/moxa/moxart_ether.c b/drivers/net/ethernet/moxa/moxart_ether.c
index edd1dab2ec43..22d0bf4a21e7 100644
--- a/drivers/net/ethernet/moxa/moxart_ether.c
+++ b/drivers/net/ethernet/moxa/moxart_ether.c
@@ -71,15 +71,23 @@ static int moxart_set_mac_address(struct net_device *ndev, void *addr)
return 0;
}
-static void moxart_mac_free_memory(struct net_device *ndev)
+static void moxart_mac_unmap_rx(struct moxart_mac_priv_t *priv)
{
- struct moxart_mac_priv_t *priv = netdev_priv(ndev);
int i;
for (i = 0; i < RX_DESC_NUM; i++)
- if (priv->rx_mapping[i])
+ if (priv->rx_mapping[i]) {
dma_unmap_single(&priv->pdev->dev, priv->rx_mapping[i],
priv->rx_buf_size, DMA_FROM_DEVICE);
+ priv->rx_mapping[i] = 0;
+ }
+}
+
+static void moxart_mac_free_memory(struct net_device *ndev)
+{
+ struct moxart_mac_priv_t *priv = netdev_priv(ndev);
+
+ moxart_mac_unmap_rx(priv);
if (priv->tx_desc_base)
dma_free_coherent(&priv->pdev->dev,
@@ -205,6 +213,7 @@ static int moxart_mac_stop(struct net_device *ndev)
/* disable all functions */
writel(0, priv->base + REG_MAC_CTRL);
+ moxart_mac_unmap_rx(priv);
return 0;
}
--
2.32.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null
2022-08-18 18:29 [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Sergei Antonov
2022-08-18 18:29 ` [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas Sergei Antonov
@ 2022-08-18 19:18 ` Andrew Lunn
2022-08-19 7:27 ` Sergei Antonov
1 sibling, 1 reply; 7+ messages in thread
From: Andrew Lunn @ 2022-08-18 19:18 UTC (permalink / raw)
To: Sergei Antonov; +Cc: netdev, Jakub Kicinski, Vladimir Oltean
On Thu, Aug 18, 2022 at 09:29:47PM +0300, Sergei Antonov wrote:
> It fixes a warning during error unwinding:
>
> WARNING: CPU: 0 PID: 1 at kernel/dma/debug.c:963 check_unmap+0x704/0x980
> DMA-API: moxart-ethernet 92000000.mac: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=1600 bytes]
> CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0+ #60
> Hardware name: Generic DT based system
> unwind_backtrace from show_stack+0x10/0x14
> show_stack from dump_stack_lvl+0x34/0x44
> dump_stack_lvl from __warn+0xbc/0x1f0
> __warn from warn_slowpath_fmt+0x94/0xc8
> warn_slowpath_fmt from check_unmap+0x704/0x980
> check_unmap from debug_dma_unmap_page+0x8c/0x9c
> debug_dma_unmap_page from moxart_mac_free_memory+0x3c/0xa8
> moxart_mac_free_memory from moxart_mac_probe+0x190/0x218
> moxart_mac_probe from platform_probe+0x48/0x88
> platform_probe from really_probe+0xc0/0x2e4
>
> Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver")
> Signed-off-by: Sergei Antonov <saproj@gmail.com>
This looks correct as it is:
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
But i do wonder how it go into the situation:
for (i = 0; i < RX_DESC_NUM; i++) {
desc = priv->rx_desc_base + i * RX_REG_DESC_SIZE;
memset(desc, 0, RX_REG_DESC_SIZE);
moxart_desc_write(RX_DESC0_DMA_OWN, desc + RX_REG_OFFSET_DESC0);
moxart_desc_write(RX_BUF_SIZE & RX_DESC1_BUF_SIZE_MASK,
desc + RX_REG_OFFSET_DESC1);
priv->rx_buf[i] = priv->rx_buf_base + priv->rx_buf_size * i;
priv->rx_mapping[i] = dma_map_single(&ndev->dev,
priv->rx_buf[i],
priv->rx_buf_size,
DMA_FROM_DEVICE);
if (dma_mapping_error(&ndev->dev, priv->rx_mapping[i]))
netdev_err(ndev, "DMA mapping error\n");
moxart_desc_write(priv->rx_mapping[i],
desc + RX_REG_OFFSET_DESC2 + RX_DESC2_ADDRESS_PHYS);
moxart_desc_write((uintptr_t)priv->rx_buf[i],
desc + RX_REG_OFFSET_DESC2 + RX_DESC2_ADDRESS_VIRT);
}
There is no way out of this, such that it only allocates some but not
all. So maybe there was an dma_mapping_error, it printed: DMA mapping
error, but kept going? So maybe another patch would be good, making
moxart_mac_setup_desc_ring() return an error when something goes
wrong?
Andrew
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas
2022-08-18 18:29 ` [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas Sergei Antonov
@ 2022-08-18 19:27 ` Andrew Lunn
2022-08-19 8:12 ` Sergei Antonov
0 siblings, 1 reply; 7+ messages in thread
From: Andrew Lunn @ 2022-08-18 19:27 UTC (permalink / raw)
To: Sergei Antonov; +Cc: netdev, Jakub Kicinski, Vladimir Oltean
On Thu, Aug 18, 2022 at 09:29:48PM +0300, Sergei Antonov wrote:
> Fix the warning poping up after bringing the link down, then up:
> ip link set dev eth0 down
> ip link set dev eth0 up
>
> WARNING: CPU: 0 PID: 55 at kernel/dma/debug.c:570 add_dma_entry+0x204/0x2ec
> DMA-API: moxart-ethernet 92000000.mac: cacheline tracking EEXIST, overlapping mappings aren't supported
> CPU: 0 PID: 55 Comm: ip Not tainted 5.19.0+ #57
> Hardware name: Generic DT based system
> unwind_backtrace from show_stack+0x10/0x14
> show_stack from dump_stack_lvl+0x34/0x44
> dump_stack_lvl from __warn+0xbc/0x1f0
> __warn from warn_slowpath_fmt+0x94/0xc8
> warn_slowpath_fmt from add_dma_entry+0x204/0x2ec
> add_dma_entry from dma_map_page_attrs+0x110/0x328
> dma_map_page_attrs from moxart_mac_open+0x134/0x320
> moxart_mac_open from __dev_open+0x11c/0x1ec
> __dev_open from __dev_change_flags+0x194/0x22c
> __dev_change_flags from dev_change_flags+0x14/0x44
> dev_change_flags from devinet_ioctl+0x6d4/0x93c
> devinet_ioctl from inet_ioctl+0x1ac/0x25c
>
> Unmap RX memory areas in moxart_mac_stop(), so that moxart_mac_open()
> will map them anew instead of double-mapping. To avoid code duplication,
> create a new function moxart_mac_unmap_rx(). Nullify unmapped pointers to
> prevent double-unmapping (ex: moxart_mac_stop(), then moxart_remove()).
This makes the code symmetric, which is good.
However, moxart_mac_free_memory() will also free the descriptors,
which is not required. moxart_remove() should undo what the probe did,
nothing more.
Andrew
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null
2022-08-18 19:18 ` [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Andrew Lunn
@ 2022-08-19 7:27 ` Sergei Antonov
0 siblings, 0 replies; 7+ messages in thread
From: Sergei Antonov @ 2022-08-19 7:27 UTC (permalink / raw)
To: Andrew Lunn; +Cc: netdev, Jakub Kicinski, Vladimir Oltean
On Thu, 18 Aug 2022 at 22:18, Andrew Lunn <andrew@lunn.ch> wrote:
>
> On Thu, Aug 18, 2022 at 09:29:47PM +0300, Sergei Antonov wrote:
> > It fixes a warning during error unwinding:
> >
> > WARNING: CPU: 0 PID: 1 at kernel/dma/debug.c:963 check_unmap+0x704/0x980
> > DMA-API: moxart-ethernet 92000000.mac: device driver tries to free DMA memory it has not allocated [device address=0x0000000000000000] [size=1600 bytes]
> > CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0+ #60
> > Hardware name: Generic DT based system
> > unwind_backtrace from show_stack+0x10/0x14
> > show_stack from dump_stack_lvl+0x34/0x44
> > dump_stack_lvl from __warn+0xbc/0x1f0
> > __warn from warn_slowpath_fmt+0x94/0xc8
> > warn_slowpath_fmt from check_unmap+0x704/0x980
> > check_unmap from debug_dma_unmap_page+0x8c/0x9c
> > debug_dma_unmap_page from moxart_mac_free_memory+0x3c/0xa8
> > moxart_mac_free_memory from moxart_mac_probe+0x190/0x218
> > moxart_mac_probe from platform_probe+0x48/0x88
> > platform_probe from really_probe+0xc0/0x2e4
> >
> > Fixes: 6c821bd9edc9 ("net: Add MOXA ART SoCs ethernet driver")
> > Signed-off-by: Sergei Antonov <saproj@gmail.com>
>
> This looks correct as it is:
>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
>
> But i do wonder how it go into the situation:
An error during moxart_mac_probe() does "goto init_fail;" which calls
moxart_mac_free_memory(). And by that time, priv->rx_mapping[i] are
all zero yet.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas
2022-08-18 19:27 ` Andrew Lunn
@ 2022-08-19 8:12 ` Sergei Antonov
2022-08-19 11:00 ` Vladimir Oltean
0 siblings, 1 reply; 7+ messages in thread
From: Sergei Antonov @ 2022-08-19 8:12 UTC (permalink / raw)
To: Andrew Lunn; +Cc: netdev, Jakub Kicinski, Vladimir Oltean
On Thu, 18 Aug 2022 at 22:27, Andrew Lunn <andrew@lunn.ch> wrote:
> > Unmap RX memory areas in moxart_mac_stop(), so that moxart_mac_open()
> > will map them anew instead of double-mapping. To avoid code duplication,
> > create a new function moxart_mac_unmap_rx(). Nullify unmapped pointers to
> > prevent double-unmapping (ex: moxart_mac_stop(), then moxart_remove()).
>
> This makes the code symmetric, which is good.
>
> However, moxart_mac_free_memory() will also free the descriptors,
> which is not required. moxart_remove() should undo what the probe did,
> nothing more.
Having considered your comments, I now think I should make another
patch, which fixes two problems at once. To unmap DMA areas only in
moxart_mac_stop() and not in moxart_remove(). It will fix error
unwinding during probe and double-mapping on link down, link up. It
will be correct if Linux always calls moxart_mac_stop() before calling
moxart_remove().
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas
2022-08-19 8:12 ` Sergei Antonov
@ 2022-08-19 11:00 ` Vladimir Oltean
0 siblings, 0 replies; 7+ messages in thread
From: Vladimir Oltean @ 2022-08-19 11:00 UTC (permalink / raw)
To: Sergei Antonov; +Cc: Andrew Lunn, netdev, Jakub Kicinski
On Fri, Aug 19, 2022 at 11:12:11AM +0300, Sergei Antonov wrote:
> On Thu, 18 Aug 2022 at 22:27, Andrew Lunn <andrew@lunn.ch> wrote:
> > > Unmap RX memory areas in moxart_mac_stop(), so that moxart_mac_open()
> > > will map them anew instead of double-mapping. To avoid code duplication,
> > > create a new function moxart_mac_unmap_rx(). Nullify unmapped pointers to
> > > prevent double-unmapping (ex: moxart_mac_stop(), then moxart_remove()).
> >
> > This makes the code symmetric, which is good.
> >
> > However, moxart_mac_free_memory() will also free the descriptors,
> > which is not required. moxart_remove() should undo what the probe did,
> > nothing more.
>
> Having considered your comments, I now think I should make another
> patch, which fixes two problems at once. To unmap DMA areas only in
> moxart_mac_stop() and not in moxart_remove(). It will fix error
> unwinding during probe and double-mapping on link down, link up. It
> will be correct if Linux always calls moxart_mac_stop() before calling
> moxart_remove().
The way this is supposed to work is that from moxart_remove() you call
unregister_netdev(), and this calls dev_close[_many]() internally. The
dev_close() method calls your ndo_stop callback.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-08-19 11:00 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-18 18:29 [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Sergei Antonov
2022-08-18 18:29 ` [PATCH 2/2] net: moxa: prevent double-mapping of DMA areas Sergei Antonov
2022-08-18 19:27 ` Andrew Lunn
2022-08-19 8:12 ` Sergei Antonov
2022-08-19 11:00 ` Vladimir Oltean
2022-08-18 19:18 ` [PATCH 1/2] net: moxa: do not call dma_unmap_single() with null Andrew Lunn
2022-08-19 7:27 ` Sergei Antonov
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