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2009-01-21dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy.Paul Mundt
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>
2009-01-21dma-coherent: per-device coherent area is in pages, not bytes.Adrian McMenamin
Commit 58c6d3dfe436eb8cfb451981d8fdc9044eaf42da ("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>
2009-01-06dma-coherent: catch oversized requests to dma_alloc_from_coherent()Johannes Weiner
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>
2009-01-06dma_alloc_coherent: clean it upAndrew Morton
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>
2009-01-06dma_alloc_from_coherent(): fix fallback to generic memoryAndrew Morton
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>
2008-08-22dma-coherent: export dma_[alloc|release]_from_coherent methodsIngo Molnar
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>
2008-08-07DMA: make dma-coherent.c documentation kdoc-friendlyDmitry Baryshkov
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>
2008-08-05dma: fix order calculation in dma_mark_declared_memory_occupied()Jan Beulich
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>
2008-07-20dma-coherent: add documentation to new interfacesDmitry Baryshkov
Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-18Generic dma-coherent: fix DMA_MEMORY_EXCLUSIVEDmitry Baryshkov
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>
2008-06-30generic: per-device coherent dma allocatorDmitry Baryshkov
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>