Commit graph

11 commits

Author SHA1 Message Date
Paul Mundt
0609697eab dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy.
When doing large allocations (larger than the per-device coherent area)
the generic memory allocators are silently fallen back on regardless of
consideration for the per-device constraints.

In the DMA_MEMORY_EXCLUSIVE case falling back on generic memory is not
an option, as it tends not to be addressable by the DMA hardware in
question. This issue showed up with the 8139too breakage on the
Dreamcast, where non-addressable buffers were silently allocated due to
the size mismatch calculation -- while it should have simply errored out
upon being unable to satisfy the allocation with the given device
constraints.

This restores fall back behaviour to what it was before the oversized
request change caused multiple regressions.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-01-21 18:51:53 +09:00
Adrian McMenamin
cdf57cab27 dma-coherent: per-device coherent area is in pages, not bytes.
Commit 58c6d3dfe4 ("dma-coherent: catch
oversized requests to dma_alloc_from_coherent()") attempted to add a
sanity check to bail out on allocations larger than the coherent area.

Unfortunately when this was implemented, the fact the coherent area
is tracked in pages rather than bytes was overlooked, which subsequently
broke every single dma_alloc_from_coherent() user, forcing the allocation
silently through generic memory instead.

Signed-off-by: Adrian McMenamin <adrian@mcmen.demon.co.uk >
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-01-21 18:47:38 +09:00
Johannes Weiner
58c6d3dfe4 dma-coherent: catch oversized requests to dma_alloc_from_coherent()
Prevent passing an order to bitmap_find_free_region() that is larger than
the actual bitmap can represent.

These requests can come from device drivers that have no idea how big the
dma region is and need to rely on dma_alloc_from_coherent() to sort it out
for them.

Reported-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:31 -08:00
Andrew Morton
eccd83e116 dma_alloc_coherent: clean it up
This thing was rather stupidly coded.  Rework it all prior to making
changes.

Also, rename local variable `page': kernel readers expect something called
`page' to have type `struct page *'.

Cc: Guennadi Liakhovetski <lg@denx.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:31 -08:00
Andrew Morton
0bef3c2dc7 dma_alloc_from_coherent(): fix fallback to generic memory
If bitmap_find_free_region() fails and DMA_MEMORY_EXCLUSIVE is not set,
the function will fail to write anything to *ret and will return 1.             This will cause dma_alloc_coherent() to return an uninitialised value,
crashing the kernel, perhaps via DMA to a random address.

Fix that by changing it to return zero in this case, so the caller will
proceed to allocate the memory from the generic memory allocator.

Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:30 -08:00
Ingo Molnar
a38409fbb5 dma-coherent: export dma_[alloc|release]_from_coherent methods
fixes modular builds:

  ERROR: "dma_alloc_from_coherent" [sound/core/snd-page-alloc.ko] undefined!
  ERROR: "dma_release_from_coherent" [sound/core/snd-page-alloc.ko] undefined!

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-22 08:34:53 +02:00
Dmitry Baryshkov
cb3952bf78 DMA: make dma-coherent.c documentation kdoc-friendly
Spotted by Randy.

Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-08-07 06:52:01 -07:00
Jan Beulich
d2dc1f4adb dma: fix order calculation in dma_mark_declared_memory_occupied()
get_order() takes byte-sized input, not a page-granular one.

Irrespective of this fix I'm inclined to believe that this doesn't work
right anyway - bitmap_allocate_region() has an implicit assumption of
'pos' being suitable for 'order', which this function doesn't seem to
enforce (and since it's being called with a byte-granular value there's no
reason to believe that the callers would make sure device_addr is passed
accordingly - it's also not documented that way).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-05 14:33:49 -07:00
Dmitry Baryshkov
b6d4f7e3ef dma-coherent: add documentation to new interfaces
Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-20 21:22:00 +02:00
Dmitry Baryshkov
538c29d43e Generic dma-coherent: fix DMA_MEMORY_EXCLUSIVE
Don't rewrite successfull allocation return values
in case the memory was marked with DMA_MEMORY_EXCLUSIVE.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18 21:14:01 +02:00
Dmitry Baryshkov
ee7e5516be generic: per-device coherent dma allocator
Currently x86_32, sh and cris-v32 provide per-device coherent dma
memory allocator.

However their implementation is nearly identical. Refactor out
common code to be reused by them.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-30 12:51:05 +02:00