nvme-fc: introduce struct nvme_fcp_op_w_sgl

This patch does not change any functionality but makes the intent of the
code more clear.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index d838987fffe1..fdadc9464f6f 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -20,6 +20,7 @@
 #include <uapi/scsi/fc/fc_fs.h>
 #include <uapi/scsi/fc/fc_els.h>
 #include <linux/delay.h>
+#include <linux/overflow.h>
 
 #include "nvme.h"
 #include "fabrics.h"
@@ -104,6 +105,12 @@ struct nvme_fc_fcp_op {
         struct nvme_fc_ersp_iu  rsp_iu;
 };
 
+struct nvme_fcp_op_w_sgl {
+        struct nvme_fc_fcp_op   op;
+        struct scatterlist      sgl[SG_CHUNK_SIZE];
+        uint8_t                 priv[0];
+};
+
 struct nvme_fc_lport {
         struct nvme_fc_local_port       localport;
 
@@ -1686,6 +1693,8 @@ __nvme_fc_init_request(struct nvme_fc_ctrl *ctrl,
                 struct nvme_fc_queue *queue, struct nvme_fc_fcp_op *op,
                 struct request *rq, u32 rqno)
 {
+        struct nvme_fcp_op_w_sgl *op_w_sgl =
+                container_of(op, typeof(*op_w_sgl), op);
         struct nvme_fc_cmd_iu *cmdiu = &op->cmd_iu;
         int ret = 0;
 
@@ -1695,7 +1704,7 @@ __nvme_fc_init_request(struct nvme_fc_ctrl *ctrl,
         op->fcp_req.rspaddr = &op->rsp_iu;
         op->fcp_req.rsplen = sizeof(op->rsp_iu);
         op->fcp_req.done = nvme_fc_fcpio_done;
-        op->fcp_req.first_sgl = (struct scatterlist *)&op[1];
+        op->fcp_req.first_sgl = &op_w_sgl->sgl[0];
         op->fcp_req.private = &op->fcp_req.first_sgl[SG_CHUNK_SIZE];
         op->ctrl = ctrl;
         op->queue = queue;
@@ -1734,12 +1743,12 @@ nvme_fc_init_request(struct blk_mq_tag_set *set, struct request *rq,
                 unsigned int hctx_idx, unsigned int numa_node)
 {
         struct nvme_fc_ctrl *ctrl = set->driver_data;
-        struct nvme_fc_fcp_op *op = blk_mq_rq_to_pdu(rq);
+        struct nvme_fcp_op_w_sgl *op = blk_mq_rq_to_pdu(rq);
         int queue_idx = (set == &ctrl->tag_set) ? hctx_idx + 1 : 0;
         struct nvme_fc_queue *queue = &ctrl->queues[queue_idx];
 
         nvme_req(rq)->ctrl = &ctrl->ctrl;
-        return __nvme_fc_init_request(ctrl, queue, op, rq, queue->rqcnt++);
+        return __nvme_fc_init_request(ctrl, queue, &op->op, rq, queue->rqcnt++);
 }
 
 static int
@@ -2423,10 +2432,9 @@ nvme_fc_create_io_queues(struct nvme_fc_ctrl *ctrl)
         ctrl->tag_set.reserved_tags = 1; /* fabric connect */
         ctrl->tag_set.numa_node = NUMA_NO_NODE;
         ctrl->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
-        ctrl->tag_set.cmd_size = sizeof(struct nvme_fc_fcp_op) +
-                                        (SG_CHUNK_SIZE *
-                                                sizeof(struct scatterlist)) +
-                                        ctrl->lport->ops->fcprqst_priv_sz;
+        ctrl->tag_set.cmd_size =
+                struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
+                            ctrl->lport->ops->fcprqst_priv_sz);
         ctrl->tag_set.driver_data = ctrl;
         ctrl->tag_set.nr_hw_queues = ctrl->ctrl.queue_count - 1;
         ctrl->tag_set.timeout = NVME_IO_TIMEOUT;
@@ -3028,10 +3036,9 @@ nvme_fc_init_ctrl(struct device *dev, struct nvmf_ctrl_options *opts,
         ctrl->admin_tag_set.queue_depth = NVME_AQ_MQ_TAG_DEPTH;
         ctrl->admin_tag_set.reserved_tags = 2; /* fabric connect + Keep-Alive */
         ctrl->admin_tag_set.numa_node = NUMA_NO_NODE;
-        ctrl->admin_tag_set.cmd_size = sizeof(struct nvme_fc_fcp_op) +
-                                        (SG_CHUNK_SIZE *
-                                                sizeof(struct scatterlist)) +
-                                        ctrl->lport->ops->fcprqst_priv_sz;
+        ctrl->admin_tag_set.cmd_size =
+                struct_size((struct nvme_fcp_op_w_sgl *)NULL, priv,
+                            ctrl->lport->ops->fcprqst_priv_sz);
         ctrl->admin_tag_set.driver_data = ctrl;
         ctrl->admin_tag_set.nr_hw_queues = 1;
         ctrl->admin_tag_set.timeout = ADMIN_TIMEOUT;