[PATCH] NVMe: code simplification and reuse.

From: Parav Pandit
Date: Tue Jun 02 2015 - 04:42:51 EST


From: Parav Pandit <parav.pandit@xxxxxxxxxxxxx>

Moved SQ doorbell pressing code to smaller function to avoid
code duplication at 3 places.
nvme_submit_cmd is low level posting function which never fails. Removed
checks around its return status which was always success.

Signed-off-by: Parav Pandit <Parav.pandit@xxxxxxxxxxxxx>
---
drivers/block/nvme-core.c | 50 +++++++++++++++++++-------------------------
1 files changed, 22 insertions(+), 28 deletions(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 58041c7..5961ed7 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -372,7 +372,8 @@ static void *nvme_finish_cmd(struct nvme_queue *nvmeq, int tag,
*
* Safe to use from interrupt context
*/
-static int __nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
+static void __nvme_submit_cmd(struct nvme_queue *nvmeq,
+ struct nvme_command *cmd)
{
u16 tail = nvmeq->sq_tail;

@@ -381,18 +382,15 @@ static int __nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
tail = 0;
writel(tail, nvmeq->q_db);
nvmeq->sq_tail = tail;
-
- return 0;
}

-static int nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
+static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
{
unsigned long flags;
- int ret;
+
spin_lock_irqsave(&nvmeq->q_lock, flags);
- ret = __nvme_submit_cmd(nvmeq, cmd);
+ __nvme_submit_cmd(nvmeq, cmd);
spin_unlock_irqrestore(&nvmeq->q_lock, flags);
- return ret;
}

static __le64 **iod_list(struct nvme_iod *iod)
@@ -709,6 +707,13 @@ int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod, int total_len,
return total_len;
}

+static inline void nvme_update_sq_tail_db(struct nvme_queue *nvmeq)
+{
+ if (++nvmeq->sq_tail == nvmeq->q_depth)
+ nvmeq->sq_tail = 0;
+ writel(nvmeq->sq_tail, nvmeq->q_db);
+}
+
/*
* We reuse the small pool to allocate the 16-byte range here as it is not
* worth having a special pool for these or additional cases to handle freeing
@@ -733,9 +738,7 @@ static void nvme_submit_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
cmnd->dsm.nr = 0;
cmnd->dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);

- if (++nvmeq->sq_tail == nvmeq->q_depth)
- nvmeq->sq_tail = 0;
- writel(nvmeq->sq_tail, nvmeq->q_db);
+ nvme_update_sq_tail_db(nvmeq);
}

static void nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
@@ -748,13 +751,11 @@ static void nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,
cmnd->common.command_id = cmdid;
cmnd->common.nsid = cpu_to_le32(ns->ns_id);

- if (++nvmeq->sq_tail == nvmeq->q_depth)
- nvmeq->sq_tail = 0;
- writel(nvmeq->sq_tail, nvmeq->q_db);
+ nvme_update_sq_tail_db(nvmeq);
}

-static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
- struct nvme_ns *ns)
+static void nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
+ struct nvme_ns *ns)
{
struct request *req = iod_get_private(iod);
struct nvme_command *cmnd;
@@ -800,11 +801,7 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
cmnd->rw.control = cpu_to_le16(control);
cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);

- if (++nvmeq->sq_tail == nvmeq->q_depth)
- nvmeq->sq_tail = 0;
- writel(nvmeq->sq_tail, nvmeq->q_db);
-
- return 0;
+ nvme_update_sq_tail_db(nvmeq);
}

static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
@@ -1034,7 +1031,8 @@ static int nvme_submit_async_admin_req(struct nvme_dev *dev)
c.common.command_id = req->tag;

blk_mq_free_hctx_request(nvmeq->hctx, req);
- return __nvme_submit_cmd(nvmeq, &c);
+ __nvme_submit_cmd(nvmeq, &c);
+ return 0;
}

static int nvme_submit_admin_async_cmd(struct nvme_dev *dev,
@@ -1057,7 +1055,8 @@ static int nvme_submit_admin_async_cmd(struct nvme_dev *dev,

cmd->common.command_id = req->tag;

- return nvme_submit_cmd(nvmeq, cmd);
+ nvme_submit_cmd(nvmeq, cmd);
+ return 0;
}

static int __nvme_submit_admin_cmd(struct nvme_dev *dev, struct nvme_command *cmd,
@@ -1246,12 +1245,7 @@ static void nvme_abort_req(struct request *req)

dev_warn(nvmeq->q_dmadev, "Aborting I/O %d QID %d\n", req->tag,
nvmeq->qid);
- if (nvme_submit_cmd(dev->queues[0], &cmd) < 0) {
- dev_warn(nvmeq->q_dmadev,
- "Could not abort I/O %d QID %d",
- req->tag, nvmeq->qid);
- blk_mq_free_request(abort_req);
- }
+ nvme_submit_cmd(dev->queues[0], &cmd);
}

static void nvme_cancel_queue_ios(struct blk_mq_hw_ctx *hctx,
--
1.7.1

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