linux-toradex.git/lib/dma-debug.c, branch v2.6.32.15

dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE and

2010-01-18T18:19:33+00:00

commit 42d53b4ff7d61487d18274ebdf1f70c1aef6f122 upstream.

There is no need to perform full BIDIR sync (copying the buffers in case
of swiotlb and similar schemes) if we know that the owner (CPU or device)
hasn't altered the data.

Addresses the false-positive reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14169

Signed-off-by: Krzysztof Halasa 
Cc: David Miller 
Cc: Joerg Roedel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

dma-debug: Fix bug causing build warning

2010-01-06T23:03:52+00:00

commit a8fe9ea200ea21421ea750423d1d4d4f7ce037cf upstream.

Stephen Rothwell reported the following build warning:

 lib/dma-debug.c: In function 'dma_debug_device_change':
 lib/dma-debug.c:680: warning: 'return' with no value, in function returning non-void

Introduced by commit f797d9881b62c2ddb1d2e7bd80d87141949c84aa
("dma-debug: Do not add notifier when dma debugging is disabled").

Return 0 [notify-done] when disabled. (this is standard bus notifier behavior.)

Signed-off-by: Shaun Ruffell 
Signed-off-by: Joerg Roedel 
Cc: Linus Torvalds 
LKML-Reference: <20091231125624.GA14666@liondog.tnic>
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

dma-debug: Do not add notifier when dma debugging is disabled.

2010-01-06T23:03:51+00:00

commit f797d9881b62c2ddb1d2e7bd80d87141949c84aa upstream.

If CONFIG_HAVE_DMA_API_DEBUG is defined and "dma_debug=off" is
specified on the kernel command line, when you detach a driver from a
device you can cause the following NULL pointer dereference:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [] dma_debug_device_change+0x5d/0x117

The problem is that the dma_debug_device_change notifier function is
added to the bus notifier chain even though the dma_entry_hash array
was never initialized.  If dma debugging is disabled, this patch both
prevents dma_debug_device_change notifiers from being added to the
chain, and additionally ensures that the dma_debug_device_change
notifier function is a no-op.

Signed-off-by: Shaun Ruffell 
Signed-off-by: Joerg Roedel 
Signed-off-by: Greg Kroah-Hartman

dma-debug: Fix compile warning with PAE enabled

2009-10-29T15:25:50+00:00

When PAE is enabled in the kernel configuration the size of
phys_addr_t differs from the size of a void pointer. The gcc
prints a warning about that in dma-debug code.
This patch fixes the warning by converting the output to
unsigned long long instead of a pointer.

Signed-off-by: Joerg Roedel

dma-debug: Fix check_unmap null pointer dereference

2009-08-21T08:04:24+00:00

While it's debatable whether or not a NULL device argument to
the DMA API functions is valid... since it certainly isn't
valid on devices with an IOMMU... dma-debug really shouldn't be
dereferencing null pointers either.

Guard against that in err_printk and the driver_filter
functions. A Fedora rawhide user was seeing this in one of the
dvb drivers resulting in an oops on boot.

[ A patch has been sent for testing to the driver, but I feel
  the dma debugging support should be fixed as well. (There's
  still a pile of legacy garbage in the kernel passing null
  pointers to dma_{alloc,free}_*. :( ]

Signed-off-by: Kyle McMartin 
Cc: mchehab@infradead.org
Cc: Joerg Roedel 
LKML-Reference: <20090820011708.GP25206@bombadil.infradead.org>
Signed-off-by: Ingo Molnar

dma-debug: Fix the overlap() function to be correct and readable

2009-07-10T20:18:45+00:00

Linus noticed how unclean and buggy the overlap() function is:

 - It uses convoluted (and bug-causing) positive checks for
   range overlap - instead of using a more natural negative
   check.

 - Even the positive checks are buggy: a positive intersection
   check has four natural cases while we checked only for three,
   missing the (addr < start && addr2 == end) case for example.

 - The variables are mis-named, making it non-obvious how the
   check was done.

 - It needlessly uses u64 instead of unsigned long. Since these
   are kernel memory pointers and we explicitly exclude highmem
   ranges anyway we cannot ever overflow 32 bits, even if we
   could. (and on 64-bit it doesnt matter anyway)

All in one, this function needs a total revamp. I used Linus's
suggestions minus the paranoid checks (we cannot overflow really
because if we get totally bad DMA ranges passed far more things
break in the systems than just DMA debugging). I also fixed a
few other small details i noticed.

Reported-by: Linus Torvalds 
Cc: Joerg Roedel 
Signed-off-by: Ingo Molnar

dma-debug: Put all hash-chain locks into the same lock class

2009-06-17T14:26:04+00:00

Alan Cox reported that lockdep runs out of its stack-trace entries
with certain configs:

 BUG: MAX_STACK_TRACE_ENTRIES too low

This happens because there are 1024 hash buckets, each with a
separate lock. Lockdep puts each lock into a separate lock class and
tracks them independently.

But in reality we never take more than one of the buckets, so they
really belong into a single lock-class. Annotate the has bucket lock
init accordingly.

[ Impact: reduce the lockdep footprint of dma-debug ]

Reported-by: Alan Cox 
Signed-off-by: Ingo Molnar 
Signed-off-by: Joerg Roedel

dma-debug: fix off-by-one error in overlap function

2009-06-16T10:29:40+00:00

This patch fixes a bug in the overlap function which returned true if
one region ends exactly before the second region begins. This is no
overlap but the function returned true in that case.

Cc: stable@kernel.org
Reported-by: Andrew Randrianasulu 
Signed-off-by: Joerg Roedel

dma-debug: be more careful when building reference entries

2009-06-15T09:10:14+00:00

The current code is not very careful when it builds reference
dma_debug_entries which get passed to hash_bucket_find(). But since this
function changed to a best-fit algorithm these entries have to be more
acurate. This patch adds this higher level of accuracy.

Signed-off-by: Joerg Roedel

dma-debug: check for sg_call_ents in best-fit algorithm too

2009-06-15T09:08:54+00:00

If we don't check for sg_call_ents the hash_bucket_find function might
still return the wrong dma_debug_entry for sg mappings.

Signed-off-by: Joerg Roedel