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Subject[PATCH v4 12/14] nvmet: Introduce helper functions to allocate and free request SGLs
Add helpers to allocate and free the SGL in a struct nvmet_req:

int nvmet_req_alloc_sgl(struct nvmet_req *req, struct nvmet_sq *sq)
void nvmet_req_free_sgl(struct nvmet_req *req)

This will be expanded in a future patch to implement peer-to-peer
memory DMAs and should be common with all target drivers. The presently
unused 'sq' argument in the alloc function will be necessary to
decide whether to use peer-to-peer memory and obtain the correct
provider to allocate the memory.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
---
drivers/nvme/target/core.c | 18 ++++++++++++++++++
drivers/nvme/target/nvmet.h | 2 ++
2 files changed, 20 insertions(+)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index e95424f172fd..75d44bc3e8d3 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -575,6 +575,24 @@ void nvmet_req_execute(struct nvmet_req *req)
}
EXPORT_SYMBOL_GPL(nvmet_req_execute);

+int nvmet_req_alloc_sgl(struct nvmet_req *req, struct nvmet_sq *sq)
+{
+ req->sg = sgl_alloc(req->transfer_len, GFP_KERNEL, &req->sg_cnt);
+ if (!req->sg)
+ return -ENOMEM;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nvmet_req_alloc_sgl);
+
+void nvmet_req_free_sgl(struct nvmet_req *req)
+{
+ sgl_free(req->sg);
+ req->sg = NULL;
+ req->sg_cnt = 0;
+}
+EXPORT_SYMBOL_GPL(nvmet_req_free_sgl);
+
static inline bool nvmet_cc_en(u32 cc)
{
return (cc >> NVME_CC_EN_SHIFT) & 0x1;
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 15fd84ab21f8..10b162615a5e 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -273,6 +273,8 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
void nvmet_req_uninit(struct nvmet_req *req);
void nvmet_req_execute(struct nvmet_req *req);
void nvmet_req_complete(struct nvmet_req *req, u16 status);
+int nvmet_req_alloc_sgl(struct nvmet_req *req, struct nvmet_sq *sq);
+void nvmet_req_free_sgl(struct nvmet_req *req);

void nvmet_cq_setup(struct nvmet_ctrl *ctrl, struct nvmet_cq *cq, u16 qid,
u16 size);
--
2.11.0
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