linux-stable.git/drivers/dma, branch v3.12.44

dmaengine: omap-dma: Fix memory leak when terminating running transfer

2015-04-22T06:58:39+00:00

commit 02d88b735f5a60f04dbf6d051b76e1877a0d0844 upstream.

In omap_dma_start_desc the vdesc->node is removed from the virt-dma
framework managed lists (to be precise from the desc_issued list).
If a terminate_all comes before the transfer finishes the omap_desc will
not be freed up because it is not in any of the lists and we stopped the
DMA channel so the transfer will not going to complete.
There is no special sequence for leaking memory when using cyclic (audio)
transfer: with every start and stop of a cyclic transfer the driver leaks
struct omap_desc worth of memory.

Free up the allocated memory directly in omap_dma_terminate_all() since the
framework will not going to do that for us.

Signed-off-by: Peter Ujfalusi 
CC: 
Signed-off-by: Vinod Koul 
Signed-off-by: Jiri Slaby

dmaengine: dw: append MODULE_ALIAS for platform driver

2015-04-09T12:14:10+00:00

commit a104a45ba7a51b5b4c5e8437020d9d48edf22f89 upstream.

The commit 9cade1a46c77 (dma: dw: split driver to library part and platform
code) introduced a separate platform driver but missed to add a
MODULE_ALIAS("platform:dw_dmac"); to that module.

The patch adds this to get driver loaded automatically if platform device is
registered.

Reported-by: "Blin, Jerome" 
Fixes: 9cade1a46c77 (dma: dw: split driver to library part and platform code)
Signed-off-by: Andy Shevchenko 
Signed-off-by: Vinod Koul 
Signed-off-by: Jiri Slaby

dmaengine: dw: don't perform DMA when dmaengine_submit is called

2014-10-13T13:41:40+00:00

commit dd8ecfcac66b4485416b2d1df0ec4798b198d7d6 upstream.

Accordingly to discussion [1] and followed up documentation the DMA controller
driver shouldn't start any DMA operations when dmaengine_submit() is called.

This patch fixes the workflow in dw_dmac driver to follow the documentation.

[1] http://www.spinics.net/lists/arm-kernel/msg125987.html

Signed-off-by: Andy Shevchenko 
Signed-off-by: Vinod Koul 
Cc: "Petallo, MauriceX R" 
Signed-off-by: Jiri Slaby

dmaengine: dw: introduce dwc_dostart_first_queued() helper

2014-10-13T13:41:39+00:00

commit e7637c6c0382485f4d2e20715d058dae6f2b6a7c upstream.

We have a duplicate code which starts first descriptor in the queue. Let's make
this as a separate helper that can be used in future as well.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Vinod Koul 
Cc: "Petallo, MauriceX R" 
Signed-off-by: Jiri Slaby

dmaengine: dw: went back to plain {request,free}_irq() calls

2014-06-09T13:53:50+00:00

commit 97977f7576a89cb9436c000ae703c0d515e748ac upstream.

The commit dbde5c29 "dw_dmac: use devm_* functions to simplify code" turns
probe function to use devm_* helpers and simultaneously brings a regression. We
need to ensure irq is disabled, followed by ensuring that don't schedule any
more tasklets and then its safe to use tasklet_kill().

The free_irq() will ensure that the irq is disabled and also wait till all
scheduled interrupts are executed by invoking synchronize_irq(). So we need to
only do tasklet_kill() after invoking free_irq().

Signed-off-by: Andy Shevchenko 
Signed-off-by: Vinod Koul 
Signed-off-by: Jiri Slaby

dma: mv_xor: Flush descriptors before activating a channel

2014-06-09T13:53:49+00:00

commit 5a9a55bf9157d3490b0c8c4c81d4708602c26e07 upstream.

We need to use writel() instead of writel_relaxed() when starting
a channel, to ensure all the descriptors have been flushed before
the activation.

While at it, remove the unneeded read-modify-write and make the
code simpler.

Signed-off-by: Lior Amsalem 
Signed-off-by: Ezequiel Garcia 
Signed-off-by: Dan Williams 
Signed-off-by: Jiri Slaby

dma: edma: fix incorrect SG list handling

2014-05-15T07:56:15+00:00

commit 5fc68a6cad658e45dca3e0a6607df3a8e5df4ef9 upstream.

The code to handle any length SG lists calls edma_resume()
even before edma_start() is called. This is incorrect
because edma_resume() enables edma events on the channel
after which CPU (in edma_start) cannot clear posted
events by writing to ECR (per the EDMA user's guide).

Because of this EDMA transfers fail to start if due
to some reason there is a pending EDMA event registered
even before EDMA transfers are started. This can happen if
an EDMA event is a byproduct of device initialization.

Fix this by calling edma_resume() only if it is not the
first batch of MAX_NR_SG elements.

Without this patch, MMC/SD fails to function on DA850 EVM
with DMA. The behaviour is triggered by specific IP and
this can explain why the issue was not reported before
(example with MMC/SD on AM335x).

Tested on DA850 EVM and AM335x EVM-SK using MMC/SD card.

Cc: Joel Fernandes 
Acked-by: Joel Fernandes 
Tested-by: Jon Ringle 
Tested-by: Alexander Holler 
Reported-by: Jon Ringle 
Signed-off-by: Sekhar Nori 
Signed-off-by: Vinod Koul 
Signed-off-by: Jiri Slaby

dma: ste_dma40: don't dereference free:d descriptor

2014-03-05T16:13:55+00:00

commit e9baa9d9d520fb0e24cca671e430689de2d4a4b2 upstream.

It appears that in the DMA40 driver the DMA tasklet will very
often dereference memory for a descriptor just free:d from the
DMA40 slab. Nothing happens because no other part of the driver
has yet had a chance to claim this memory, but it's really
nasty to dereference free:d memory, so let's check the flag
before the descriptor is free and store it in a bool variable.

Reported-by: Dan Carpenter 
Signed-off-by: Linus Walleij 
Signed-off-by: Vinod Koul 
Signed-off-by: Jiri Slaby

ioat: fix tasklet tear down

2014-03-05T16:13:53+00:00

commit da87ca4d4ca101f177fffd84f1f0a5e4c0343557 upstream.

Since commit 77873803363c "net_dma: mark broken" we no longer pin dma
engines active for the network-receive-offload use case.  As a result
the ->free_chan_resources() that occurs after the driver self test no
longer has a NET_DMA induced ->alloc_chan_resources() to back it up.  A
late firing irq can lead to ksoftirqd spinning indefinitely due to the
tasklet_disable() performed by ->free_chan_resources().  Only
->alloc_chan_resources() can clear this condition in affected kernels.

This problem has been present since commit 3e037454bcfa "I/OAT: Add
support for MSI and MSI-X" in 2.6.24, but is now exposed. Given the
NET_DMA use case is deprecated we can revisit moving the driver to use
threaded irqs.  For now, just tear down the irq and tasklet properly by:

1/ Disable the irq from triggering the tasklet

2/ Disable the irq from re-arming

3/ Flush inflight interrupts

4/ Flush the timer

5/ Flush inflight tasklets

References:
https://lkml.org/lkml/2014/1/27/282
https://lkml.org/lkml/2014/2/19/672

Cc: Ingo Molnar 
Cc: Steven Rostedt 
Reported-by: Mike Galbraith 
Reported-by: Stanislav Fomichev 
Tested-by: Mike Galbraith 
Tested-by: Stanislav Fomichev 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Dan Williams 
Signed-off-by: Jiri Slaby

net_dma: mark broken

2014-01-09T20:25:10+00:00

commit 77873803363c9e831fc1d1e6895c084279090c22 upstream.

net_dma can cause data to be copied to a stale mapping if a
copy-on-write fault occurs during dma.  The application sees missing
data.

The following trace is triggered by modifying the kernel to WARN if it
ever triggers copy-on-write on a page that is undergoing dma:

 WARNING: CPU: 24 PID: 2529 at lib/dma-debug.c:485 debug_dma_assert_idle+0xd2/0x120()
 ioatdma 0000:00:04.0: DMA-API: cpu touching an active dma mapped page [pfn=0x16bcd9]
 Modules linked in: iTCO_wdt iTCO_vendor_support ioatdma lpc_ich pcspkr dca
 CPU: 24 PID: 2529 Comm: linbug Tainted: G        W    3.13.0-rc1+ #353
  00000000000001e5 ffff88016f45f688 ffffffff81751041 ffff88017ab0ef70
  ffff88016f45f6d8 ffff88016f45f6c8 ffffffff8104ed9c ffffffff810f3646
  ffff8801768f4840 0000000000000282 ffff88016f6cca10 00007fa2bb699349
 Call Trace:
  [] dump_stack+0x46/0x58
  [] warn_slowpath_common+0x8c/0xc0
  [] ? ftrace_pid_func+0x26/0x30
  [] warn_slowpath_fmt+0x46/0x50
  [] debug_dma_assert_idle+0xd2/0x120
  [] do_wp_page+0xd0/0x790
  [] handle_mm_fault+0x51c/0xde0
  [] ? copy_user_enhanced_fast_string+0x9/0x20
  [] __do_page_fault+0x19c/0x530
  [] ? _raw_spin_lock_bh+0x16/0x40
  [] ? trace_clock_local+0x9/0x10
  [] ? rb_reserve_next_event+0x64/0x310
  [] ? ioat2_dma_prep_memcpy_lock+0x60/0x130 [ioatdma]
  [] do_page_fault+0xe/0x10
  [] page_fault+0x22/0x30
  [] ? __kfree_skb+0x51/0xd0
  [] ? copy_user_enhanced_fast_string+0x9/0x20
  [] ? memcpy_toiovec+0x52/0xa0
  [] skb_copy_datagram_iovec+0x5f/0x2a0
  [] tcp_rcv_established+0x674/0x7f0
  [] tcp_v4_do_rcv+0x2e5/0x4a0
  [..]
 ---[ end trace e30e3b01191b7617 ]---
 Mapped at:
  [] debug_dma_map_page+0xb9/0x160
  [] dma_async_memcpy_pg_to_pg+0x127/0x210
  [] dma_memcpy_pg_to_iovec+0x119/0x1f0
  [] dma_skb_copy_datagram_iovec+0x11c/0x2b0
  [] tcp_rcv_established+0x74a/0x7f0:

...the problem is that the receive path falls back to cpu-copy in
several locations and this trace is just one of the areas.  A few
options were considered to fix this:

1/ sync all dma whenever a cpu copy branch is taken

2/ modify the page fault handler to hold off while dma is in-flight

Option 1 adds yet more cpu overhead to an "offload" that struggles to compete
with cpu-copy.  Option 2 adds checks for behavior that is already documented as
broken when using get_user_pages().  At a minimum a debug mode is warranted to
catch and flag these violations of the dma-api vs get_user_pages().

Thanks to David for his reproducer.

Cc: Dave Jiang 
Cc: Vinod Koul 
Cc: Alexander Duyck 
Reported-by: David Whipple 
Acked-by: David S. Miller 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman