Hello!
This patchset replaces custom consistent dma regions usage in dma-mapping framework in favour of generic vmalloc areas created on demand for each allocation. The main purpose for this patchset is to remove 2MiB limit of dma coherent/writecombine allocations.
Atomic allocations are served from special pool preallocated on boot, becasue vmalloc areas cannot be reliably created in atomic context.
Linux v3.5-rc1 introduced a lot of changes to ARM dma-mapping subsystem (CMA and dmamap_ops based implementation has been finally merged), so the previous version of these patches is not applicable anymore. This version provides an update required for applying them on v3.5-rc2 kernel as well as some changes requested by Minchan Kim in his review.
This patch is based on vanilla v3.5-rc2 release.
Atomic allocations have been tested with s3c-sdhci driver on Samsung UniversalC210 board with dmabounce code enabled to force dma_alloc_coherent() use on each dma_map_* call (some of them are made from interrupts).
Best regards Marek Szyprowski Samsung Poland R&D Center
Changelog:
v3: - rebased onto v3.4-rc2: added support for IOMMU-aware implementation of dma-mapping calls, unified with CMA coherent dma pool - implemented changes requested by Minchan Kim: added more checks for vmarea->flags & VM_DMA, renamed some variables, removed obsole locks, squashed find_vm_area() exporting patch into the main redesign patch
v2: http://thread.gmane.org/gmane.linux.kernel.mm/78563 - added support for atomic allocations (served from preallocated pool) - minor cleanup here and there - rebased onto v3.4-rc7
v1: http://thread.gmane.org/gmane.linux.kernel.mm/76703 - initial version
Patch summary:
Marek Szyprowski (3): mm: vmalloc: use const void * for caller argument mm: vmalloc: add VM_DMA flag to indicate areas used by dma-mapping framework ARM: dma-mapping: remove custom consistent dma region
Documentation/kernel-parameters.txt | 2 +- arch/arm/include/asm/dma-mapping.h | 2 +- arch/arm/mm/dma-mapping.c | 503 ++++++++++++----------------------- include/linux/vmalloc.h | 10 +- mm/vmalloc.c | 31 ++- 5 files changed, 206 insertions(+), 342 deletions(-)