[PATCH 4/4] nvme: support ranged discard requests

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/nvme/host/core.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index efe8ec300126..ae9254fcd9c5 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -238,26 +238,36 @@ static inline void nvme_setup_flush(struct nvme_ns *ns,
 static inline int nvme_setup_discard(struct nvme_ns *ns, struct request *req,
                struct nvme_command *cmnd)
 {
+       unsigned short segments = blk_rq_nr_discard_segments(req), n = 0;
        struct nvme_dsm_range *range;
-       unsigned int nr_bytes = blk_rq_bytes(req);
+       struct bio *bio;
 
-       range = kmalloc(sizeof(*range), GFP_ATOMIC);
+       range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
        if (!range)
                return BLK_MQ_RQ_QUEUE_BUSY;
 
-       range->cattr = cpu_to_le32(0);
-       range->nlb = cpu_to_le32(nr_bytes >> ns->lba_shift);
-       range->slba = cpu_to_le64(nvme_block_nr(ns, blk_rq_pos(req)));
+       __rq_for_each_bio(bio, req) {
+               u64 slba = nvme_block_nr(ns, bio->bi_iter.bi_sector);
+               u32 nlb = bio->bi_iter.bi_size >> ns->lba_shift;
+
+               range[n].cattr = cpu_to_le32(0);
+               range[n].nlb = cpu_to_le32(nlb);
+               range[n].slba = cpu_to_le64(slba);
+               n++;
+       }
+
+       if (WARN_ON_ONCE(n != segments))
+               return BLK_MQ_RQ_QUEUE_ERROR;
 
        memset(cmnd, 0, sizeof(*cmnd));
        cmnd->dsm.opcode = nvme_cmd_dsm;
        cmnd->dsm.nsid = cpu_to_le32(ns->ns_id);
-       cmnd->dsm.nr = 0;
+       cmnd->dsm.nr = segments - 1;
        cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
 
        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);
+       req->special_vec.bv_len = sizeof(*range) * segments;
        req->rq_flags |= RQF_SPECIAL_PAYLOAD;
 
        return BLK_MQ_RQ_QUEUE_OK;
@@ -1233,6 +1243,8 @@ static void nvme_set_queue_limits(struct nvme_ctrl *ctrl,
        if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
                vwc = true;
        blk_queue_write_cache(q, vwc, vwc);
+       blk_queue_max_discard_segments(q,
+                       PAGE_SIZE / sizeof(struct nvme_dsm_range));
 }
 
 /*
-- 
2.11.0