nvme: Discard workaround for non-conformant devices
[ Upstream commit 530436c45e
]
Users observe IOMMU related errors when performing discard on nvme from
non-compliant nvme devices reading beyond the end of the DMA mapped
ranges to discard.
Two different variants of this behavior have been observed: SM22XX
controllers round up the read size to a multiple of 512 bytes, and Phison
E12 unconditionally reads the maximum discard size allowed by the spec
(256 segments or 4kB).
Make nvme_setup_discard unconditionally allocate the maximum DSM buffer
so the driver DMA maps a memory range that will always succeed.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=202665 many
Signed-off-by: Eduard Hasenleithner <eduard@hasenleithner.at>
[changelog, use existing define, kernel coding style]
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
parent
a09579b0c2
commit
8b0acb768a
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@ -611,8 +611,14 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
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struct nvme_dsm_range *range;
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struct bio *bio;
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range = kmalloc_array(segments, sizeof(*range),
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GFP_ATOMIC | __GFP_NOWARN);
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/*
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* Some devices do not consider the DSM 'Number of Ranges' field when
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* determining how much data to DMA. Always allocate memory for maximum
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* number of segments to prevent device reading beyond end of buffer.
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*/
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static const size_t alloc_size = sizeof(*range) * NVME_DSM_MAX_RANGES;
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range = kzalloc(alloc_size, GFP_ATOMIC | __GFP_NOWARN);
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if (!range) {
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/*
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* If we fail allocation our range, fallback to the controller
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@ -652,7 +658,7 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req,
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req->special_vec.bv_page = virt_to_page(range);
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req->special_vec.bv_offset = offset_in_page(range);
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req->special_vec.bv_len = sizeof(*range) * segments;
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req->special_vec.bv_len = alloc_size;
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req->rq_flags |= RQF_SPECIAL_PAYLOAD;
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return BLK_STS_OK;
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