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authorChristoph Hellwig <hch@lst.de>2018-01-17 22:04:38 +0100
committerJens Axboe <axboe@kernel.dk>2018-01-17 14:05:35 -0700
commitb0f2853b56a2acaff19cca2c6a608f8ec268d21a (patch)
treeb37a803e6a8ca66d6cc831f2d1992b3f7ef33732 /drivers/nvme
parent20469a37aed12a886d0deda5a07c04037923144a (diff)
downloadlinux-b0f2853b56a2acaff19cca2c6a608f8ec268d21a.tar.bz2
nvme-pci: take sglist coalescing in dma_map_sg into account
Some iommu implementations can merge physically and/or virtually contiguous segments inside sg_map_dma. The NVMe SGL support does not take this into account and will warn because of falling off a loop. Pass the number of mapped segments to nvme_pci_setup_sgls so that the SGL setup can take the number of mapped segments into account. Reported-by: Fangjian (Turing) <f.fangjian@huawei.com> Fixes: a7a7cbe3 ("nvme-pci: add SGL support") Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@rimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/nvme')
-rw-r--r--drivers/nvme/host/pci.c21
1 files changed, 9 insertions, 12 deletions
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a7e94cc3c70e..4276ebfff22b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -725,20 +725,19 @@ static void nvme_pci_sgl_set_seg(struct nvme_sgl_desc *sge,
}
static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
- struct request *req, struct nvme_rw_command *cmd)
+ struct request *req, struct nvme_rw_command *cmd, int entries)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- int length = blk_rq_payload_bytes(req);
struct dma_pool *pool;
struct nvme_sgl_desc *sg_list;
struct scatterlist *sg = iod->sg;
- int entries = iod->nents, i = 0;
dma_addr_t sgl_dma;
+ int i = 0;
/* setting the transfer type as SGL */
cmd->flags = NVME_CMD_SGL_METABUF;
- if (length == sg_dma_len(sg)) {
+ if (entries == 1) {
nvme_pci_sgl_set_data(&cmd->dptr.sgl, sg);
return BLK_STS_OK;
}
@@ -778,13 +777,9 @@ static blk_status_t nvme_pci_setup_sgls(struct nvme_dev *dev,
}
nvme_pci_sgl_set_data(&sg_list[i++], sg);
-
- length -= sg_dma_len(sg);
sg = sg_next(sg);
- entries--;
- } while (length > 0);
+ } while (--entries > 0);
- WARN_ON(entries > 0);
return BLK_STS_OK;
}
@@ -796,6 +791,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
enum dma_data_direction dma_dir = rq_data_dir(req) ?
DMA_TO_DEVICE : DMA_FROM_DEVICE;
blk_status_t ret = BLK_STS_IOERR;
+ int nr_mapped;
sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
iod->nents = blk_rq_map_sg(q, req, iod->sg);
@@ -803,12 +799,13 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
goto out;
ret = BLK_STS_RESOURCE;
- if (!dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, dma_dir,
- DMA_ATTR_NO_WARN))
+ nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, dma_dir,
+ DMA_ATTR_NO_WARN);
+ if (!nr_mapped)
goto out;
if (iod->use_sgl)
- ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw);
+ ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw, nr_mapped);
else
ret = nvme_pci_setup_prps(dev, req, &cmnd->rw);