mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Leon Romanovsky
37f0c7a8df
In commit eadaa8b255 ("dma-mapping: introduce new DMA attribute to
indicate MMIO memory"), DMA_ATTR_MMIO attribute was added to describe
MMIO addresses, which require to avoid any memory cache flushing, as
an outcome of the discussion pointed in Link tag below.
In case of PCI_P2PDMA_MAP_THRU_HOST_BRIDGE transfer, blk-mq-dm logic
treated this as regular page and relied on "struct page" DMA flow.
That flow performs CPU cache flushing, which shouldn't be done here,
and doesn't set IOMMU_MMIO flag in DMA-IOMMU case.
As a solution, let's encode peer-to-peer transaction type in NVMe IOD
flags variable and provide it to blk-mq-dma API.
Link: https://lore.kernel.org/all/f912c446-1ae9-4390-9c11-00dce7bf0fd3@arm.com/
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef BLK_MQ_DMA_H
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#define BLK_MQ_DMA_H
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#include <linux/blk-mq.h>
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#include <linux/pci-p2pdma.h>
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struct blk_map_iter {
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struct bvec_iter iter;
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struct bio *bio;
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struct bio_vec *bvecs;
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bool is_integrity;
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};
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struct blk_dma_iter {
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/* Output address range for this iteration */
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dma_addr_t addr;
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u32 len;
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struct pci_p2pdma_map_state p2pdma;
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/* Status code. Only valid when blk_rq_dma_map_iter_* returned false */
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blk_status_t status;
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/* Internal to blk_rq_dma_map_iter_* */
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struct blk_map_iter iter;
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};
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bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev,
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struct dma_iova_state *state, struct blk_dma_iter *iter);
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bool blk_rq_dma_map_iter_next(struct request *req, struct device *dma_dev,
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struct dma_iova_state *state, struct blk_dma_iter *iter);
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/**
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* blk_rq_dma_map_coalesce - were all segments coalesced?
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* @state: DMA state to check
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*
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* Returns true if blk_rq_dma_map_iter_start coalesced all segments into a
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* single DMA range.
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*/
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static inline bool blk_rq_dma_map_coalesce(struct dma_iova_state *state)
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{
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return dma_use_iova(state);
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}
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/**
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* blk_rq_dma_unmap - try to DMA unmap a request
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* @req: request to unmap
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* @dma_dev: device to unmap from
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* @state: DMA IOVA state
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* @mapped_len: number of bytes to unmap
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* @map: peer-to-peer mapping type
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*
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* Returns %false if the callers need to manually unmap every DMA segment
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* mapped using @iter or %true if no work is left to be done.
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*/
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static inline bool blk_rq_dma_unmap(struct request *req, struct device *dma_dev,
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struct dma_iova_state *state, size_t mapped_len,
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enum pci_p2pdma_map_type map)
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{
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if (map == PCI_P2PDMA_MAP_BUS_ADDR)
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return true;
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if (dma_use_iova(state)) {
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unsigned int attrs = 0;
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if (map == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
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attrs |= DMA_ATTR_MMIO;
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dma_iova_destroy(dma_dev, state, mapped_len, rq_dma_dir(req),
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attrs);
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return true;
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}
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return !dma_need_unmap(dma_dev);
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}
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#endif /* BLK_MQ_DMA_H */
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