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| author |   Eduard Hasenleithner <eduard@hasenleithner.at> | 2019-11-12 21:55:01 +0100 |
|---|---|---|
| committer |   Keith Busch <kbusch@kernel.org> | 2019-11-13 06:37:38 +0900 |
| commit | 530436c45ef2e446c12538a400e465929a0b3ade (patch) | |
| tree | 370f6d4b250bd2bd9f5cd26e27aa2b6e497ae017 /drivers/nvme/host/core.c | |
| parent | nvme: Add hardware monitoring support (diff) | |
| download | linux-dev-530436c45ef2e446c12538a400e465929a0b3ade.tar.xz linux-dev-530436c45ef2e446c12538a400e465929a0b3ade.zip | |
nvme: Discard workaround for non-conformant devices
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>
Diffstat (limited to '')
| -rw-r--r-- | drivers/nvme/host/core.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 4be64703aa47..9696404a6182 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -574,8 +574,14 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req, struct nvme_dsm_range *range; struct bio *bio; - range = kmalloc_array(segments, sizeof(*range), - GFP_ATOMIC | __GFP_NOWARN); + /* + * Some devices do not consider the DSM 'Number of Ranges' field when + * determining how much data to DMA. Always allocate memory for maximum + * number of segments to prevent device reading beyond end of buffer. + */ + static const size_t alloc_size = sizeof(*range) * NVME_DSM_MAX_RANGES; + + range = kzalloc(alloc_size, GFP_ATOMIC | __GFP_NOWARN); if (!range) { /* * If we fail allocation our range, fallback to the controller @@ -615,7 +621,7 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, struct request *req, req->special_vec.bv_page = virt_to_page(range); req->special_vec.bv_offset = offset_in_page(range); - req->special_vec.bv_len = sizeof(*range) * segments; + req->special_vec.bv_len = alloc_size; req->rq_flags |= RQF_SPECIAL_PAYLOAD; return BLK_STS_OK; |