On 1/11/19 10:05 AM, Andrew F. Davis wrote:
Hello all, This is a set of (hopefully) non-controversial cleanups for the ION framework and current set of heaps. These were found as I start to familiarize myself with the framework to help in whatever way I can in getting all this up to the standards needed for de-staging. I would like to get some ideas of what is left to work on to get ION out of staging. Has there been some kind of agreement on what ION should eventually end up being? To me it looks like it is being whittled away at to it's most core functions. To me that is looking like being a DMA-BUF user-space front end, simply advertising available memory backings in a system and providing allocations as DMA-BUF handles. If this is the case then it looks close to being ready to me at least, but I would love to hear any other opinions and concerns.
Yes, at this point the only functionality that people are really depending on is the ability to allocate a dma_buf easily from userspace.
Back to this patchset, the last patch may be a bit different than the others, it adds an unmapped heaps type and creation helper. I wanted to get this in to show off another heap type and maybe some issues we may have with the current ION framework. The unmapped heap is used when the backing memory should not (or cannot) be touched. Currently this kind of heap is used for firewalled secure memory that can be allocated like normal heap memory but only used by secure devices (OP-TEE, crypto HW, etc). It is basically just copied from the "carveout" heap type with the only difference being it is not mappable to userspace and we do not clear the memory (as we should not map it either). So should this really be a new heap type? Or maybe advertised as a carveout heap but with an additional allocation flag? Perhaps we do away with "types" altogether and just have flags, coherent/non-coherent, mapped/unmapped, etc. Maybe more thinking will be needed afterall..
So the cleanup looks okay (I need to finish reviewing) but I'm not a fan of adding another heaptype without solving the problem of adding some sort of devicetree binding or other method of allocating and placing Ion heaps. That plus uncached buffers are one of the big open problems that need to be solved for destaging Ion. See https://lore.kernel.org/lkml/20181120164636.jcw7li2uaa3cmwc3@DESKTOP-E1NTVVP.localdomain/ for some background on that problem. Thanks, Laura
Thanks, Andrew Andrew F. Davis (14): staging: android: ion: Add proper header information staging: android: ion: Remove empty ion_ioctl_dir() function staging: android: ion: Merge ion-ioctl.c into ion.c staging: android: ion: Remove leftover comment staging: android: ion: Remove struct ion_platform_heap staging: android: ion: Fixup some white-space issues staging: android: ion: Sync comment docs with struct ion_buffer staging: android: ion: Remove base from ion_carveout_heap staging: android: ion: Remove base from ion_chunk_heap staging: android: ion: Remove unused headers staging: android: ion: Allow heap name to be null staging: android: ion: Declare helpers for carveout and chunk heaps staging: android: ion: Do not sync CPU cache on map/unmap staging: android: ion: Add UNMAPPED heap type and helper drivers/staging/android/ion/Kconfig | 10 ++ drivers/staging/android/ion/Makefile | 3 +- drivers/staging/android/ion/ion-ioctl.c | 98 -------------- drivers/staging/android/ion/ion.c | 93 +++++++++++-- drivers/staging/android/ion/ion.h | 87 ++++++++----- .../staging/android/ion/ion_carveout_heap.c | 19 +-- drivers/staging/android/ion/ion_chunk_heap.c | 25 ++-- drivers/staging/android/ion/ion_cma_heap.c | 6 +- drivers/staging/android/ion/ion_heap.c | 8 +- drivers/staging/android/ion/ion_page_pool.c | 2 +- drivers/staging/android/ion/ion_system_heap.c | 8 +- .../staging/android/ion/ion_unmapped_heap.c | 123 ++++++++++++++++++ drivers/staging/android/uapi/ion.h | 3 + 13 files changed, 307 insertions(+), 178 deletions(-) delete mode 100644 drivers/staging/android/ion/ion-ioctl.c create mode 100644 drivers/staging/android/ion/ion_unmapped_heap.c
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