dma-mapping: allow map_sg() ops to return negative error codes

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Allow dma_map_sgtable() to pass errors from the map_sg() ops. This
will be required for returning appropriate error codes when mapping
P2PDMA memory.

Introduce __dma_map_sg_attrs() which will return the raw error code
from the map_sg operation (whether it be negative or zero). Then add a
dma_map_sg_attrs() wrapper to convert any negative errors to zero to
satisfy the existing calling convention.

dma_map_sgtable() defines three error codes that .map_sg implementations
are allowed to return: -EINVAL, -ENOMEM and -EIO. The latter of which
is a generic return for cases that are passing DMA_MAPPING_ERROR
through.

dma_map_sgtable() will convert a zero error return for old map_sg() ops
into a -EIO return and return any negative errors as reported.

This allows map_sg implementations to start returning multiple
negative error codes. Legacy map_sg implementations can continue
to return zero until they are all converted.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

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This commit is contained in:

Logan Gunthorpe 2021-07-29 14:15:19 -06:00 • committed by Christoph Hellwig

parent 173735c346

commit fffe3cc8c2

3 changed files with 84 additions and 38 deletions

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5

include/linux/dma-map-ops.h

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35

include/linux/dma-mapping.h

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82

kernel/dma/mapping.c

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