[PATCH 5/7] nvme: simplify completion handling
Christoph Hellwig
hch at lst.de
Mon Sep 21 11:40:51 PDT 2015
Now that all commands are executed as block layer requests we can remove the
internal completion in the NVMe driver. Note that we can simply call
blk_mq_complete_request to abort commands as the block layer will protect
against double copletions internally.
Signed-off-by: Christoph Hellwig <hch at lst.de>
---
drivers/block/nvme-core.c | 143 ++++++++++------------------------------------
1 file changed, 29 insertions(+), 114 deletions(-)
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index c49f07f..5649f8f 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -141,15 +141,11 @@ static inline void _nvme_check_size(void)
BUILD_BUG_ON(sizeof(struct nvme_smart_log) != 512);
}
-typedef void (*nvme_completion_fn)(struct nvme_queue *, void *,
- struct nvme_completion *);
-
struct nvme_cmd_info {
- nvme_completion_fn fn;
- void *ctx;
int aborted;
struct nvme_queue *nvmeq;
- struct nvme_iod iod[0];
+ struct nvme_iod *iod;
+ struct nvme_iod __iod[0];
};
/*
@@ -243,15 +239,6 @@ static int nvme_init_request(void *data, struct request *req,
return 0;
}
-static void nvme_set_info(struct nvme_cmd_info *cmd, void *ctx,
- nvme_completion_fn handler)
-{
- cmd->fn = handler;
- cmd->ctx = ctx;
- cmd->aborted = 0;
- blk_mq_start_request(blk_mq_rq_from_pdu(cmd));
-}
-
static void *iod_get_private(struct nvme_iod *iod)
{
return (void *) (iod->private & ~0x1UL);
@@ -265,72 +252,6 @@ static bool iod_should_kfree(struct nvme_iod *iod)
return (iod->private & NVME_INT_MASK) == 0;
}
-/* Special values must be less than 0x1000 */
-#define CMD_CTX_BASE ((void *)POISON_POINTER_DELTA)
-#define CMD_CTX_CANCELLED (0x30C + CMD_CTX_BASE)
-#define CMD_CTX_COMPLETED (0x310 + CMD_CTX_BASE)
-#define CMD_CTX_INVALID (0x314 + CMD_CTX_BASE)
-
-static void special_completion(struct nvme_queue *nvmeq, void *ctx,
- struct nvme_completion *cqe)
-{
- if (ctx == CMD_CTX_CANCELLED)
- return;
- if (ctx == CMD_CTX_COMPLETED) {
- dev_warn(nvmeq->q_dmadev,
- "completed id %d twice on queue %d\n",
- cqe->command_id, le16_to_cpup(&cqe->sq_id));
- return;
- }
- if (ctx == CMD_CTX_INVALID) {
- dev_warn(nvmeq->q_dmadev,
- "invalid id %d completed on queue %d\n",
- cqe->command_id, le16_to_cpup(&cqe->sq_id));
- return;
- }
- dev_warn(nvmeq->q_dmadev, "Unknown special completion %p\n", ctx);
-}
-
-static void *cancel_cmd_info(struct nvme_cmd_info *cmd, nvme_completion_fn *fn)
-{
- void *ctx;
-
- if (fn)
- *fn = cmd->fn;
- ctx = cmd->ctx;
- cmd->fn = special_completion;
- cmd->ctx = CMD_CTX_CANCELLED;
- return ctx;
-}
-
-static inline struct nvme_cmd_info *get_cmd_from_tag(struct nvme_queue *nvmeq,
- unsigned int tag)
-{
- struct request *req = blk_mq_tag_to_rq(*nvmeq->tags, tag);
-
- return blk_mq_rq_to_pdu(req);
-}
-
-/*
- * Called with local interrupts disabled and the q_lock held. May not sleep.
- */
-static void *nvme_finish_cmd(struct nvme_queue *nvmeq, int tag,
- nvme_completion_fn *fn)
-{
- struct nvme_cmd_info *cmd = get_cmd_from_tag(nvmeq, tag);
- void *ctx;
- if (tag >= nvmeq->q_depth) {
- *fn = special_completion;
- return CMD_CTX_INVALID;
- }
- if (fn)
- *fn = cmd->fn;
- ctx = cmd->ctx;
- cmd->fn = special_completion;
- cmd->ctx = CMD_CTX_COMPLETED;
- return ctx;
-}
-
/**
* __nvme_submit_cmd() - Copy a command into a queue and ring the doorbell
* @nvmeq: The queue to use
@@ -394,7 +315,7 @@ static struct nvme_iod *nvme_alloc_iod(struct request *rq, struct nvme_dev *dev,
size <= NVME_INT_BYTES(dev)) {
struct nvme_cmd_info *cmd = blk_mq_rq_to_pdu(rq);
- iod = cmd->iod;
+ iod = cmd->__iod;
iod_init(iod, size, rq->nr_phys_segments,
(unsigned long) rq | NVME_INT_MASK);
return iod;
@@ -543,13 +464,15 @@ static void nvme_init_integrity(struct nvme_ns *ns)
}
#endif
-static void req_completion(struct nvme_queue *nvmeq, void *ctx,
- struct nvme_completion *cqe)
+/*
+ * Called with local interrupts disabled and the q_lock held. May not sleep.
+ */
+static void nvme_finish_cmd(struct nvme_queue *nvmeq,
+ struct nvme_completion *cqe)
{
- struct nvme_iod *iod = ctx;
- struct request *req = iod_get_private(iod);
+ struct request *req = blk_mq_tag_to_rq(*nvmeq->tags, cqe->command_id);
struct nvme_cmd_info *cmd_rq = blk_mq_rq_to_pdu(req);
-
+ struct nvme_iod *iod = cmd_rq->iod;
u16 status = le16_to_cpup(&cqe->status) >> 1;
if (unlikely(status)) {
@@ -565,12 +488,8 @@ static void req_completion(struct nvme_queue *nvmeq, void *ctx,
return;
}
- if (req->cmd_type == REQ_TYPE_DRV_PRIV) {
- if (cmd_rq->ctx == CMD_CTX_CANCELLED)
- status = -EINTR;
- } else {
+ if (req->cmd_type != REQ_TYPE_DRV_PRIV)
status = nvme_error_status(status);
- }
}
if (req->cmd_type == REQ_TYPE_DRV_PRIV) {
@@ -863,7 +782,10 @@ static int nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
}
}
- nvme_set_info(cmd, iod, req_completion);
+ cmd->iod = iod;
+ cmd->aborted = 0;
+ blk_mq_start_request(req);
+
spin_lock_irq(&nvmeq->q_lock);
if (req->cmd_type == REQ_TYPE_DRV_PRIV)
nvme_submit_priv(nvmeq, req, iod);
@@ -894,8 +816,6 @@ static int nvme_process_cq(struct nvme_queue *nvmeq)
phase = nvmeq->cq_phase;
for (;;) {
- void *ctx;
- nvme_completion_fn fn;
struct nvme_completion cqe = nvmeq->cqes[head];
if ((le16_to_cpu(cqe.status) & 1) != phase)
break;
@@ -904,8 +824,14 @@ static int nvme_process_cq(struct nvme_queue *nvmeq)
head = 0;
phase = !phase;
}
- ctx = nvme_finish_cmd(nvmeq, cqe.command_id, &fn);
- fn(nvmeq, ctx, &cqe);
+
+ if (unlikely(cqe.command_id >= nvmeq->q_depth)) {
+ dev_warn(nvmeq->q_dmadev,
+ "invalid id %d completed on queue %d\n",
+ cqe.command_id, le16_to_cpu(cqe.sq_id));
+ continue;
+ }
+ nvme_finish_cmd(nvmeq, &cqe);
}
/* If the controller ignores the cq head doorbell and continuously
@@ -1297,29 +1223,18 @@ static void nvme_abort_req(struct request *req)
static void nvme_cancel_queue_ios(struct request *req, void *data, bool reserved)
{
struct nvme_queue *nvmeq = data;
- void *ctx;
- nvme_completion_fn fn;
- struct nvme_cmd_info *cmd;
- struct nvme_completion cqe;
if (!blk_mq_request_started(req))
return;
- cmd = blk_mq_rq_to_pdu(req);
-
- if (cmd->ctx == CMD_CTX_CANCELLED)
- return;
-
- if (blk_queue_dying(req->q))
- cqe.status = cpu_to_le16((NVME_SC_ABORT_REQ | NVME_SC_DNR) << 1);
- else
- cqe.status = cpu_to_le16(NVME_SC_ABORT_REQ << 1);
-
-
dev_warn(nvmeq->q_dmadev, "Cancelling I/O %d QID %d\n",
req->tag, nvmeq->qid);
- ctx = cancel_cmd_info(cmd, &fn);
- fn(nvmeq, ctx, &cqe);
+
+ /*
+ * Use a negative Linux errno here so that the submitter can
+ * distinguish between hardware and driver errors.
+ */
+ blk_mq_complete_request(req, -EINTR);
}
static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)
--
1.9.1
More information about the Linux-nvme
mailing list