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authorEduard Hasenleithner <eduard@hasenleithner.at>2019-11-12 21:55:01 +0100
committerKeith Busch <kbusch@kernel.org>2019-11-13 06:37:38 +0900
commit530436c45ef2e446c12538a400e465929a0b3ade (patch)
tree370f6d4b250bd2bd9f5cd26e27aa2b6e497ae017 /drivers/nvme/host
parent400b6a7b13a3fd71cff087139ce45dd1e5fff444 (diff)
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 'drivers/nvme/host')
-rw-r--r--drivers/nvme/host/core.c12
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;