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| author | James Smart <jsmart2021@gmail.com> | 2019-03-13 20:55:00 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-03-13 21:05:39 +0300 |
| commit | 9f7d8ae2f79479ce13d987c8f3b1500b8937fc5d (patch) | |
| tree | 22e4aa1b3354b7d721a5908c96949f2491dfeddf /drivers/nvme | |
| parent | d11de63f2b519f0a162b834013b6d3a46dbf3886 (diff) | |
| download | linux-9f7d8ae2f79479ce13d987c8f3b1500b8937fc5d.tar.xz | |
nvme-fc: use nr_phys_segments to determine existence of sgl
For some nvme command, when issued by the nvme core layer, there
is an internal buffer which can cause blk_rq_payload_bytes() to
return a non-zero value yet there is no actual/real command payload
and sg list. An example is the WRITE ZEROES command.
To address this, when making choices on whether to dma map an sgl,
use blk_rq_nr_phys_segments() instead of blk_rq_payload_bytes().
When there is a sgl, blk_rq_payload_bytes() will return the amount
of data to be transferred by the sgl.
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/nvme')
| -rw-r--r-- | drivers/nvme/host/fc.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c index b29b12498a1a..ba8f2a9cbdaf 100644 --- a/drivers/nvme/host/fc.c +++ b/drivers/nvme/host/fc.c @@ -2107,7 +2107,7 @@ nvme_fc_map_data(struct nvme_fc_ctrl *ctrl, struct request *rq, freq->sg_cnt = 0; - if (!blk_rq_payload_bytes(rq)) + if (!blk_rq_nr_phys_segments(rq)) return 0; freq->sg_table.sgl = freq->first_sgl; @@ -2304,12 +2304,23 @@ nvme_fc_queue_rq(struct blk_mq_hw_ctx *hctx, if (ret) return ret; - data_len = blk_rq_payload_bytes(rq); - if (data_len) + /* + * nvme core doesn't quite treat the rq opaquely. Commands such + * as WRITE ZEROES will return a non-zero rq payload_bytes yet + * there is no actual payload to be transferred. + * To get it right, key data transmission on there being 1 or + * more physical segments in the sg list. If there is no + * physical segments, there is no payload. + */ + if (blk_rq_nr_phys_segments(rq)) { + data_len = blk_rq_payload_bytes(rq); io_dir = ((rq_data_dir(rq) == WRITE) ? NVMEFC_FCP_WRITE : NVMEFC_FCP_READ); - else + } else { + data_len = 0; io_dir = NVMEFC_FCP_NODATA; + } + return nvme_fc_start_fcp_op(ctrl, queue, op, data_len, io_dir); } |