linux/kernel/dma/direct.c, branch v5.17

dma-direct: add a dma_direct_use_pool helper

2021-12-08T15:46:35Z

Add a helper to check if a potentially blocking operation should dip into the atomic pools. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: factor the swiotlb code out of __dma_direct_alloc_pages

2021-12-07T11:50:10Z

Add a new helper to deal with the swiotlb case. This keeps the code nicely boundled and removes the not required call to dma_direct_optimal_gfp_mask for the swiotlb case. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: drop two CONFIG_DMA_RESTRICTED_POOL conditionals

2021-12-07T11:50:10Z

swiotlb_alloc and swiotlb_free are properly stubbed out if CONFIG_DMA_RESTRICTED_POOL is not set, so skip the extra checks. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: warn if there is no pool for force unencrypted allocations

2021-12-07T11:50:10Z

Instead of blindly running into a blocking operation for a non-blocking gfp, return NULL and spew an error. Note that Kconfig prevents this for all currently relevant platforms, and this is just a debug check. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: fail allocations that can't be made coherent

2021-12-07T11:50:06Z

If the architecture can't remap or set an address uncached there is no way to fullfill a request for a coherent allocation. Return NULL in that case. Note that this case currently does not happen, so this is a theoretical fixup and/or a preparation for eventually supporting platforms that can't support coherent allocations with the generic code. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: refactor the !coherent checks in dma_direct_alloc

2021-12-07T11:49:57Z

Add a big central !dev_is_dma_coherent(dev) block to deal with as much as of the uncached allocation schemes and document the schemes a bit better. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL_MAPPING allocations

2021-12-07T11:49:50Z

Split the code for DMA_ATTR_NO_KERNEL_MAPPING allocations into a separate helper to make dma_direct_alloc a little more readable. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy Acked-by: David Rientjes

dma-direct: clean up the remapping checks in dma_direct_alloc

2021-12-07T11:48:09Z

Add two local variables to track if we want to remap the returned address using vmap or call dma_set_uncached and use that to simplify the code flow. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: always leak memory that can't be re-encrypted

2021-12-07T11:47:38Z

We must never let unencrypted memory go back into the general page pool. So if we fail to set it back to encrypted when freeing DMA memory, leak the memory instead and warn the user. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy

dma-direct: don't call dma_set_decrypted for remapped allocations

2021-12-07T11:47:06Z

Remapped allocations handle the encrypted bit through the pgprot passed to vmap, so there is no call dma_set_decrypted. Note that this case is currently entirely theoretical as no valid kernel configuration supports remapped allocations and memory encryption currently. Signed-off-by: Christoph Hellwig