From: David Brownell <[email protected]>
At91_mci is abusing dma_free_coherent(), which may not be called
with IRQs disabled. I saw "mkfs.ext3" on an MMC card objecting
voluminously as each write completed:
WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224()
[<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>] (warn_on_slowpath+0x4c/0x68)
[<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>] (dma_free_coherent+0x2c/0x224)
r6:00008008 r5:ffc06000 r4:00000000
[<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>] (at91_mci_irq+0x374/0x420)
[<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>] (handle_IRQ_event+0x2c/0x6c)
...
This bug has been around for a LONG time. The MM warning is
from late 2005, but the driver merged a year later ... so I'm
puzzled why nobody noticed this before now.
The fix involves noting that this buffer shouldn't be DMA-coherent;
it's just used for normal DMA writes. So replace it with standard
kmalloc() buffering and DMA mapping calls.
This is the quickie fix. A better one would not rely on allocating
large bounce buffers. (Note that dma_alloc_coherent could have failed
too, but that case was ignored... kmalloc is a bit more likely to
fail though.)
Signed-off-by: David Brownell <[email protected]>
---
drivers/mmc/host/at91_mci.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -621,12 +621,21 @@ static void at91_mci_send_command(struct
if (cpu_is_at91sam9260 () || cpu_is_at91sam9263())
if (host->total_length < 12)
host->total_length = 12;
- host->buffer = dma_alloc_coherent(NULL,
- host->total_length,
- &host->physical_address, GFP_KERNEL);
+
+ host->buffer = kmalloc(host->total_length, GFP_KERNEL);
+ if (!host->buffer) {
+ pr_debug("Can't alloc tx buffer\n");
+ cmd->error = -ENOMEM;
+ mmc_request_done(host->mmc, host->request);
+ return;
+ }
at91_mci_sg_to_dma(host, data);
+ host->physical_address = dma_map_single(NULL,
+ host->buffer, host->total_length,
+ DMA_TO_DEVICE);
+
pr_debug("Transmitting %d bytes\n", host->total_length);
at91_mci_write(host, ATMEL_PDC_TPR, host->physical_address);
@@ -694,7 +703,10 @@ static void at91_mci_completed_command(s
cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3));
if (host->buffer) {
- dma_free_coherent(NULL, host->total_length, host->buffer, host->physical_address);
+ dma_unmap_single(NULL,
+ host->physical_address, host->total_length,
+ DMA_TO_DEVICE);
+ kfree(host->buffer);
host->buffer = NULL;
}
Ok with you nicolas?
On Mon, 18 Aug 2008 16:07:21 -0700
David Brownell <[email protected]> wrote:
> From: David Brownell <[email protected]>
>
> At91_mci is abusing dma_free_coherent(), which may not be called
> with IRQs disabled. I saw "mkfs.ext3" on an MMC card objecting
> voluminously as each write completed:
>
> WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224()
> [<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>] (warn_on_slowpath+0x4c/0x68)
> [<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>] (dma_free_coherent+0x2c/0x224)
> r6:00008008 r5:ffc06000 r4:00000000
> [<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>] (at91_mci_irq+0x374/0x420)
> [<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>] (handle_IRQ_event+0x2c/0x6c)
> ...
>
> This bug has been around for a LONG time. The MM warning is
> from late 2005, but the driver merged a year later ... so I'm
> puzzled why nobody noticed this before now.
>
> The fix involves noting that this buffer shouldn't be DMA-coherent;
> it's just used for normal DMA writes. So replace it with standard
> kmalloc() buffering and DMA mapping calls.
>
> This is the quickie fix. A better one would not rely on allocating
> large bounce buffers. (Note that dma_alloc_coherent could have failed
> too, but that case was ignored... kmalloc is a bit more likely to
> fail though.)
>
> Signed-off-by: David Brownell <[email protected]>
>
> ---
> drivers/mmc/host/at91_mci.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> --- a/drivers/mmc/host/at91_mci.c
> +++ b/drivers/mmc/host/at91_mci.c
> @@ -621,12 +621,21 @@ static void at91_mci_send_command(struct
> if (cpu_is_at91sam9260 () || cpu_is_at91sam9263())
> if (host->total_length < 12)
> host->total_length = 12;
> - host->buffer = dma_alloc_coherent(NULL,
> - host->total_length,
> - &host->physical_address, GFP_KERNEL);
> +
> + host->buffer = kmalloc(host->total_length, GFP_KERNEL);
> + if (!host->buffer) {
> + pr_debug("Can't alloc tx buffer\n");
> + cmd->error = -ENOMEM;
> + mmc_request_done(host->mmc, host->request);
> + return;
> + }
>
> at91_mci_sg_to_dma(host, data);
>
> + host->physical_address = dma_map_single(NULL,
> + host->buffer, host->total_length,
> + DMA_TO_DEVICE);
> +
> pr_debug("Transmitting %d bytes\n", host->total_length);
>
> at91_mci_write(host, ATMEL_PDC_TPR, host->physical_address);
> @@ -694,7 +703,10 @@ static void at91_mci_completed_command(s
> cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3));
>
> if (host->buffer) {
> - dma_free_coherent(NULL, host->total_length, host->buffer, host->physical_address);
> + dma_unmap_single(NULL,
> + host->physical_address, host->total_length,
> + DMA_TO_DEVICE);
> + kfree(host->buffer);
> host->buffer = NULL;
> }
>
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org
WARNING: This correspondence is being monitored by the
Swedish government. Make sure your server uses encryption
for SMTP traffic and consider using PGP for end-to-end
encryption.
Pierre, Andrew,
You can add my...
David Brownell :
> From: David Brownell <[email protected]>
>
> At91_mci is abusing dma_free_coherent(), which may not be called
> with IRQs disabled. I saw "mkfs.ext3" on an MMC card objecting
> voluminously as each write completed:
>
> WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224()
> [<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>] (warn_on_slowpath+0x4c/0x68)
> [<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>] (dma_free_coherent+0x2c/0x224)
> r6:00008008 r5:ffc06000 r4:00000000
> [<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>] (at91_mci_irq+0x374/0x420)
> [<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>] (handle_IRQ_event+0x2c/0x6c)
> ...
>
> This bug has been around for a LONG time. The MM warning is
> from late 2005, but the driver merged a year later ... so I'm
> puzzled why nobody noticed this before now.
>
> The fix involves noting that this buffer shouldn't be DMA-coherent;
> it's just used for normal DMA writes. So replace it with standard
> kmalloc() buffering and DMA mapping calls.
>
> This is the quickie fix. A better one would not rely on allocating
> large bounce buffers. (Note that dma_alloc_coherent could have failed
> too, but that case was ignored... kmalloc is a bit more likely to
> fail though.)
>
> Signed-off-by: David Brownell <[email protected]>
...
Signed-off-by: Nicolas Ferre <[email protected]>
--
Nicolas Ferre
Pierre, Andrew,
Based on Andrew comments, I rewrite this email..
You can add my...
> David Brownell :
>> From: David Brownell <[email protected]>
>>
>> At91_mci is abusing dma_free_coherent(), which may not be called
>> with IRQs disabled. I saw "mkfs.ext3" on an MMC card objecting
>> voluminously as each write completed:
>>
>> WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224()
>> [<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>]
>> (warn_on_slowpath+0x4c/0x68)
>> [<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>]
>> (dma_free_coherent+0x2c/0x224)
>> r6:00008008 r5:ffc06000 r4:00000000
>> [<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>]
>> (at91_mci_irq+0x374/0x420)
>> [<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>]
>> (handle_IRQ_event+0x2c/0x6c)
>> ...
>>
>> This bug has been around for a LONG time. The MM warning is
>> from late 2005, but the driver merged a year later ... so I'm
>> puzzled why nobody noticed this before now.
>>
>> The fix involves noting that this buffer shouldn't be DMA-coherent;
>> it's just used for normal DMA writes. So replace it with standard
>> kmalloc() buffering and DMA mapping calls.
>>
>> This is the quickie fix. A better one would not rely on allocating
>> large bounce buffers. (Note that dma_alloc_coherent could have failed
>> too, but that case was ignored... kmalloc is a bit more likely to
>> fail though.)
>>
>> Signed-off-by: David Brownell <[email protected]>
>
> ...
Acked-by: Nicolas Ferre <[email protected]>
Kind regards,
--
Nicolas Ferre
On Fri, 22 Aug 2008 10:40:30 +0200
Nicolas Ferre <[email protected]> wrote:
> >>
> >> Signed-off-by: David Brownell <[email protected]>
> >
> > ...
>
> Acked-by: Nicolas Ferre <[email protected]>
>
I have nothing else in my queue, so Andrew, as I suspect you have other
things going to Linus, if you could please include this one as well. :)
Acked-by: Pierre Ossman <[email protected]>
Rgds
--
-- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org
WARNING: This correspondence is being monitored by the
Swedish government. Make sure your server uses encryption
for SMTP traffic and consider using PGP for end-to-end
encryption.
On Wed, 27 Aug 2008 21:01:05 +0200
Pierre Ossman <[email protected]> wrote:
> On Fri, 22 Aug 2008 10:40:30 +0200
> Nicolas Ferre <[email protected]> wrote:
>
> > >>
> > >> Signed-off-by: David Brownell <[email protected]>
> > >
> > > ...
> >
> > Acked-by: Nicolas Ferre <[email protected]>
> >
>
> I have nothing else in my queue, so Andrew, as I suspect you have other
> things going to Linus, if you could please include this one as well. :)
No probs, thanks.