NVMe: Retry failed commands with non-fatal errors

For commands returned with failed status, queue these for resubmission
and continue retrying them until success or for a limited amount of
time. The final timeout was arbitrarily chosen so requests can't be
retried indefinitely.

Since these are requeued on the nvmeq that submitted the command, the
callbacks have to take an nvmeq instead of an nvme_dev as a parameter
so that we can use the locked queue to append the iod to retry later.

The nvme_iod conviently can be used to track how long we've been trying
to successfully complete an iod request. The nvme_iod also provides the
nvme prp dma mappings, so I had to move a few things around so we can
keep those mappings.

Signed-off-by: Keith Busch <[e-mail]>
[fixed checkpatch issue with long line]
Signed-off-by: Matthew Wilcox <[e-mail]>

drivers/block/nvme-core.c

···
 #define SQ_SIZE(depth)		(depth * sizeof(struct nvme_command))
 #define CQ_SIZE(depth)		(depth * sizeof(struct nvme_completion))
 #define ADMIN_TIMEOUT	(60 * HZ)
+#define IOD_TIMEOUT	(4 * NVME_IO_TIMEOUT)
 
 unsigned char io_timeout = 30;
 module_param(io_timeout, byte, 0644);
···
 	wait_queue_head_t sq_full;
 	wait_queue_t sq_cong_wait;
 	struct bio_list sq_cong;
+	struct list_head iod_bio;
 	u32 __iomem *q_db;
 	u16 q_depth;
 	u16 cq_vector;
···
 	BUILD_BUG_ON(sizeof(struct nvme_smart_log) != 512);
 }
 
-typedef void (*nvme_completion_fn)(struct nvme_dev *, void *,
+typedef void (*nvme_completion_fn)(struct nvme_queue *, void *,
 						struct nvme_completion *);
 
 struct nvme_cmd_info {
···
 #define CMD_CTX_FLUSH		(0x318 + CMD_CTX_BASE)
 #define CMD_CTX_ABORT		(0x31C + CMD_CTX_BASE)
 
-static void special_completion(struct nvme_dev *dev, void *ctx,
+static void special_completion(struct nvme_queue *nvmeq, void *ctx,
 						struct nvme_completion *cqe)
 {
 	if (ctx == CMD_CTX_CANCELLED)
···
 	if (ctx == CMD_CTX_FLUSH)
 		return;
 	if (ctx == CMD_CTX_ABORT) {
-		++dev->abort_limit;
+		++nvmeq->dev->abort_limit;
 		return;
 	}
 	if (ctx == CMD_CTX_COMPLETED) {
-		dev_warn(&dev->pci_dev->dev,
+		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(&dev->pci_dev->dev,
+		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(&dev->pci_dev->dev, "Unknown special completion %p\n", ctx);
+	dev_warn(nvmeq->q_dmadev, "Unknown special completion %p\n", ctx);
 }
 
-static void async_completion(struct nvme_dev *dev, void *ctx,
+static void async_completion(struct nvme_queue *nvmeq, void *ctx,
 						struct nvme_completion *cqe)
 {
 	struct async_cmd_info *cmdinfo = ctx;
···
 		iod->npages = -1;
 		iod->length = nbytes;
 		iod->nents = 0;
+		iod->first_dma = 0ULL;
 		iod->start_time = jiffies;
 	}
 
···
 	part_stat_unlock();
 }
 
-static void bio_completion(struct nvme_dev *dev, void *ctx,
+static void bio_completion(struct nvme_queue *nvmeq, void *ctx,
 						struct nvme_completion *cqe)
 {
 	struct nvme_iod *iod = ctx;
 	struct bio *bio = iod->private;
 	u16 status = le16_to_cpup(&cqe->status) >> 1;
 
+	if (unlikely(status)) {
+		if (!(status & NVME_SC_DNR ||
+				bio->bi_rw & REQ_FAILFAST_MASK) &&
+				(jiffies - iod->start_time) < IOD_TIMEOUT) {
+			if (!waitqueue_active(&nvmeq->sq_full))
+				add_wait_queue(&nvmeq->sq_full,
+							&nvmeq->sq_cong_wait);
+			list_add_tail(&iod->node, &nvmeq->iod_bio);
+			wake_up(&nvmeq->sq_full);
+			return;
+		}
+	}
 	if (iod->nents) {
-		dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
+		dma_unmap_sg(nvmeq->q_dmadev, iod->sg, iod->nents,
 			bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
 		nvme_end_io_acct(bio, iod->start_time);
 	}
-	nvme_free_iod(dev, iod);
+	nvme_free_iod(nvmeq->dev, iod);
 	if (status)
 		bio_endio(bio, -EIO);
 	else
···
 }
 
 /* length is in bytes.  gfp flags indicates whether we may sleep. */
-int nvme_setup_prps(struct nvme_dev *dev, struct nvme_common_command *cmd,
-			struct nvme_iod *iod, int total_len, gfp_t gfp)
+int nvme_setup_prps(struct nvme_dev *dev, struct nvme_iod *iod, int total_len,
+								gfp_t gfp)
 {
 	struct dma_pool *pool;
 	int length = total_len;
···
 	dma_addr_t prp_dma;
 	int nprps, i;
 
-	cmd->prp1 = cpu_to_le64(dma_addr);
 	length -= (PAGE_SIZE - offset);
 	if (length <= 0)
 		return total_len;
···
 	}
 
 	if (length <= PAGE_SIZE) {
-		cmd->prp2 = cpu_to_le64(dma_addr);
+		iod->first_dma = dma_addr;
 		return total_len;
 	}
 
···
 
 	prp_list = dma_pool_alloc(pool, gfp, &prp_dma);
 	if (!prp_list) {
-		cmd->prp2 = cpu_to_le64(dma_addr);
+		iod->first_dma = dma_addr;
 		iod->npages = -1;
 		return (total_len - length) + PAGE_SIZE;
 	}
 	list[0] = prp_list;
 	iod->first_dma = prp_dma;
-	cmd->prp2 = cpu_to_le64(prp_dma);
 	i = 0;
 	for (;;) {
 		if (i == PAGE_SIZE / 8) {
···
 
 	bio_chain(split, bio);
 
-	if (bio_list_empty(&nvmeq->sq_cong))
+	if (!waitqueue_active(&nvmeq->sq_full))
 		add_wait_queue(&nvmeq->sq_full, &nvmeq->sq_cong_wait);
 	bio_list_add(&nvmeq->sq_cong, split);
 	bio_list_add(&nvmeq->sq_cong, bio);
+	wake_up(&nvmeq->sq_full);
 
 	return 0;
 }
···
 	return length;
 }
 
-/*
- * 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
- * the iod.
- */
 static int nvme_submit_discard(struct nvme_queue *nvmeq, struct nvme_ns *ns,
 		struct bio *bio, struct nvme_iod *iod, int cmdid)
 {
-	struct nvme_dsm_range *range;
+	struct nvme_dsm_range *range =
+				(struct nvme_dsm_range *)iod_list(iod)[0];
 	struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
-
-	range = dma_pool_alloc(nvmeq->dev->prp_small_pool, GFP_ATOMIC,
-							&iod->first_dma);
-	if (!range)
-		return -ENOMEM;
-
-	iod_list(iod)[0] = (__le64 *)range;
-	iod->npages = 0;
 
 	range->cattr = cpu_to_le32(0);
 	range->nlb = cpu_to_le32(bio->bi_iter.bi_size >> ns->lba_shift);
···
 	return nvme_submit_flush(nvmeq, ns, cmdid);
 }
 
-/*
- * Called with local interrupts disabled and the q_lock held.  May not sleep.
- */
-static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
-								struct bio *bio)
+static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod)
 {
+	struct bio *bio = iod->private;
+	struct nvme_ns *ns = bio->bi_bdev->bd_disk->private_data;
 	struct nvme_command *cmnd;
-	struct nvme_iod *iod;
-	enum dma_data_direction dma_dir;
-	int cmdid, length, result;
+	int cmdid;
 	u16 control;
 	u32 dsmgmt;
-	int psegs = bio_phys_segments(ns->queue, bio);
 
-	if ((bio->bi_rw & REQ_FLUSH) && psegs) {
-		result = nvme_submit_flush_data(nvmeq, ns);
-		if (result)
-			return result;
-	}
-
-	result = -ENOMEM;
-	iod = nvme_alloc_iod(psegs, bio->bi_iter.bi_size, GFP_ATOMIC);
-	if (!iod)
-		goto nomem;
-	iod->private = bio;
-
-	result = -EBUSY;
 	cmdid = alloc_cmdid(nvmeq, iod, bio_completion, NVME_IO_TIMEOUT);
 	if (unlikely(cmdid < 0))
-		goto free_iod;
+		return cmdid;
 
-	if (bio->bi_rw & REQ_DISCARD) {
-		result = nvme_submit_discard(nvmeq, ns, bio, iod, cmdid);
-		if (result)
-			goto free_cmdid;
-		return result;
-	}
-	if ((bio->bi_rw & REQ_FLUSH) && !psegs)
+	if (bio->bi_rw & REQ_DISCARD)
+		return nvme_submit_discard(nvmeq, ns, bio, iod, cmdid);
+	if ((bio->bi_rw & REQ_FLUSH) && !iod->nents)
 		return nvme_submit_flush(nvmeq, ns, cmdid);
 
 	control = 0;
···
 		dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;
 
 	cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];
-
 	memset(cmnd, 0, sizeof(*cmnd));
-	if (bio_data_dir(bio)) {
-		cmnd->rw.opcode = nvme_cmd_write;
-		dma_dir = DMA_TO_DEVICE;
-	} else {
-		cmnd->rw.opcode = nvme_cmd_read;
-		dma_dir = DMA_FROM_DEVICE;
-	}
 
-	result = nvme_map_bio(nvmeq, iod, bio, dma_dir, psegs);
-	if (result <= 0)
-		goto free_cmdid;
-	length = result;
-
+	cmnd->rw.opcode = bio_data_dir(bio) ? nvme_cmd_write : nvme_cmd_read;
 	cmnd->rw.command_id = cmdid;
 	cmnd->rw.nsid = cpu_to_le32(ns->ns_id);
-	length = nvme_setup_prps(nvmeq->dev, &cmnd->common, iod, length,
-								GFP_ATOMIC);
+	cmnd->rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+	cmnd->rw.prp2 = cpu_to_le64(iod->first_dma);
 	cmnd->rw.slba = cpu_to_le64(nvme_block_nr(ns, bio->bi_iter.bi_sector));
-	cmnd->rw.length = cpu_to_le16((length >> ns->lba_shift) - 1);
+	cmnd->rw.length =
+		cpu_to_le16((bio->bi_iter.bi_size >> ns->lba_shift) - 1);
 	cmnd->rw.control = cpu_to_le16(control);
 	cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
 
-	nvme_start_io_acct(bio);
 	if (++nvmeq->sq_tail == nvmeq->q_depth)
 		nvmeq->sq_tail = 0;
 	writel(nvmeq->sq_tail, nvmeq->q_db);
 
 	return 0;
+}
 
- free_cmdid:
-	free_cmdid(nvmeq, cmdid, NULL);
+/*
+ * Called with local interrupts disabled and the q_lock held.  May not sleep.
+ */
+static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
+								struct bio *bio)
+{
+	struct nvme_iod *iod;
+	int psegs = bio_phys_segments(ns->queue, bio);
+	int result;
+
+	if ((bio->bi_rw & REQ_FLUSH) && psegs) {
+		result = nvme_submit_flush_data(nvmeq, ns);
+		if (result)
+			return result;
+	}
+
+	iod = nvme_alloc_iod(psegs, bio->bi_iter.bi_size, GFP_ATOMIC);
+	if (!iod)
+		return -ENOMEM;
+
+	iod->private = bio;
+	if (bio->bi_rw & REQ_DISCARD) {
+		void *range;
+		/*
+		 * 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 the iod.
+		 */
+		range = dma_pool_alloc(nvmeq->dev->prp_small_pool,
+						GFP_ATOMIC,
+						&iod->first_dma);
+		if (!range) {
+			result = -ENOMEM;
+			goto free_iod;
+		}
+		iod_list(iod)[0] = (__le64 *)range;
+		iod->npages = 0;
+	} else if (psegs) {
+		result = nvme_map_bio(nvmeq, iod, bio,
+			bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE,
+			psegs);
+		if (result <= 0)
+			goto free_iod;
+		if (nvme_setup_prps(nvmeq->dev, iod, result, GFP_ATOMIC) !=
+								result) {
+			result = -ENOMEM;
+			goto free_iod;
+		}
+		nvme_start_io_acct(bio);
+	}
+	if (unlikely(nvme_submit_iod(nvmeq, iod))) {
+		if (!waitqueue_active(&nvmeq->sq_full))
+			add_wait_queue(&nvmeq->sq_full, &nvmeq->sq_cong_wait);
+		list_add_tail(&iod->node, &nvmeq->iod_bio);
+	}
+	return 0;
+
  free_iod:
 	nvme_free_iod(nvmeq->dev, iod);
- nomem:
 	return result;
 }
 
···
 		}
 
 		ctx = free_cmdid(nvmeq, cqe.command_id, &fn);
-		fn(nvmeq->dev, ctx, &cqe);
+		fn(nvmeq, ctx, &cqe);
 	}
 
 	/* If the controller ignores the cq head doorbell and continuously
···
 	if (!nvmeq->q_suspended && bio_list_empty(&nvmeq->sq_cong))
 		result = nvme_submit_bio_queue(nvmeq, ns, bio);
 	if (unlikely(result)) {
-		if (bio_list_empty(&nvmeq->sq_cong))
+		if (!waitqueue_active(&nvmeq->sq_full))
 			add_wait_queue(&nvmeq->sq_full, &nvmeq->sq_cong_wait);
 		bio_list_add(&nvmeq->sq_cong, bio);
 	}
···
 	int status;
 };
 
-static void sync_completion(struct nvme_dev *dev, void *ctx,
+static void sync_completion(struct nvme_queue *nvmeq, void *ctx,
 						struct nvme_completion *cqe)
 {
 	struct sync_cmd_info *cmdinfo = ctx;
···
 		dev_warn(nvmeq->q_dmadev, "Cancelling I/O %d QID %d\n", cmdid,
 								nvmeq->qid);
 		ctx = cancel_cmdid(nvmeq, cmdid, &fn);
-		fn(nvmeq->dev, ctx, &cqe);
+		fn(nvmeq, ctx, &cqe);
 	}
 }
 
···
 	while (bio_list_peek(&nvmeq->sq_cong)) {
 		struct bio *bio = bio_list_pop(&nvmeq->sq_cong);
 		bio_endio(bio, -EIO);
+	}
+	while (!list_empty(&nvmeq->iod_bio)) {
+		static struct nvme_completion cqe = {
+			.status = cpu_to_le16(
+				(NVME_SC_ABORT_REQ | NVME_SC_DNR) << 1),
+		};
+		struct nvme_iod *iod = list_first_entry(&nvmeq->iod_bio,
+							struct nvme_iod,
+							node);
+		list_del(&iod->node);
+		bio_completion(nvmeq, iod, &cqe);
 	}
 	spin_unlock_irq(&nvmeq->q_lock);
 
···
 	init_waitqueue_head(&nvmeq->sq_full);
 	init_waitqueue_entry(&nvmeq->sq_cong_wait, nvme_thread);
 	bio_list_init(&nvmeq->sq_cong);
+	INIT_LIST_HEAD(&nvmeq->iod_bio);
 	nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
 	nvmeq->q_depth = depth;
 	nvmeq->cq_vector = vector;
···
 		c.rw.metadata = cpu_to_le64(meta_dma_addr);
 	}
 
-	length = nvme_setup_prps(dev, &c.common, iod, length, GFP_KERNEL);
+	length = nvme_setup_prps(dev, iod, length, GFP_KERNEL);
+	c.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+	c.rw.prp2 = cpu_to_le64(iod->first_dma);
 
 	if (length != (io.nblocks + 1) << ns->lba_shift)
 		status = -ENOMEM;
···
 								length);
 		if (IS_ERR(iod))
 			return PTR_ERR(iod);
-		length = nvme_setup_prps(dev, &c.common, iod, length,
-								GFP_KERNEL);
+		length = nvme_setup_prps(dev, iod, length, GFP_KERNEL);
+		c.common.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+		c.common.prp2 = cpu_to_le64(iod->first_dma);
 	}
 
 	timeout = cmd.timeout_ms ? msecs_to_jiffies(cmd.timeout_ms) :
···
 	.getgeo		= nvme_getgeo,
 };
 
+static void nvme_resubmit_iods(struct nvme_queue *nvmeq)
+{
+	struct nvme_iod *iod, *next;
+
+	list_for_each_entry_safe(iod, next, &nvmeq->iod_bio, node) {
+		if (unlikely(nvme_submit_iod(nvmeq, iod)))
+			break;
+		list_del(&iod->node);
+		if (bio_list_empty(&nvmeq->sq_cong) &&
+						list_empty(&nvmeq->iod_bio))
+			remove_wait_queue(&nvmeq->sq_full,
+						&nvmeq->sq_cong_wait);
+	}
+}
+
 static void nvme_resubmit_bios(struct nvme_queue *nvmeq)
 {
 	while (bio_list_peek(&nvmeq->sq_cong)) {
 		struct bio *bio = bio_list_pop(&nvmeq->sq_cong);
 		struct nvme_ns *ns = bio->bi_bdev->bd_disk->private_data;
 
-		if (bio_list_empty(&nvmeq->sq_cong))
+		if (bio_list_empty(&nvmeq->sq_cong) &&
+						list_empty(&nvmeq->iod_bio))
 			remove_wait_queue(&nvmeq->sq_full,
 							&nvmeq->sq_cong_wait);
 		if (nvme_submit_bio_queue(nvmeq, ns, bio)) {
-			if (bio_list_empty(&nvmeq->sq_cong))
+			if (!waitqueue_active(&nvmeq->sq_full))
 				add_wait_queue(&nvmeq->sq_full,
 							&nvmeq->sq_cong_wait);
 			bio_list_add_head(&nvmeq->sq_cong, bio);
···
 				nvme_process_cq(nvmeq);
 				nvme_cancel_ios(nvmeq, true);
 				nvme_resubmit_bios(nvmeq);
+				nvme_resubmit_iods(nvmeq);
  unlock:
 				spin_unlock_irq(&nvmeq->q_lock);
 			}

drivers/block/nvme-scsi.c

···
 			res = PTR_ERR(iod);
 			goto out;
 		}
-		length = nvme_setup_prps(dev, &c.common, iod, tot_len,
-								GFP_KERNEL);
+		length = nvme_setup_prps(dev, iod, tot_len, GFP_KERNEL);
 		if (length != tot_len) {
 			res = -ENOMEM;
 			goto out_unmap;
 		}
 
+		c.dlfw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+		c.dlfw.prp2 = cpu_to_le64(iod->first_dma);
 		c.dlfw.numd = cpu_to_le32((tot_len/BYTES_TO_DWORDS) - 1);
 		c.dlfw.offset = cpu_to_le32(offset/BYTES_TO_DWORDS);
 	} else if (opcode == nvme_admin_activate_fw) {
···
 			res = PTR_ERR(iod);
 			goto out;
 		}
-		retcode = nvme_setup_prps(dev, &c.common, iod, unit_len,
-							GFP_KERNEL);
+		retcode = nvme_setup_prps(dev, iod, unit_len, GFP_KERNEL);
 		if (retcode != unit_len) {
 			nvme_unmap_user_pages(dev,
 				(is_write) ? DMA_TO_DEVICE : DMA_FROM_DEVICE,
···
 			res = -ENOMEM;
 			goto out;
 		}
+		c.rw.prp1 = cpu_to_le64(sg_dma_address(iod->sg));
+		c.rw.prp2 = cpu_to_le64(iod->first_dma);
 
 		nvme_offset += unit_num_blocks;
 

include/linux/nvme.h

···
 	int length;		/* Of data, in bytes */
 	unsigned long start_time;
 	dma_addr_t first_dma;
+	struct list_head node;
 	struct scatterlist sg[0];
 };
 
···
  */
 void nvme_free_iod(struct nvme_dev *dev, struct nvme_iod *iod);
 
-int nvme_setup_prps(struct nvme_dev *dev, struct nvme_common_command *cmd,
-			struct nvme_iod *iod, int total_len, gfp_t gfp);
+int nvme_setup_prps(struct nvme_dev *, struct nvme_iod *, int , gfp_t);
 struct nvme_iod *nvme_map_user_pages(struct nvme_dev *dev, int write,
 				unsigned long addr, unsigned length);
 void nvme_unmap_user_pages(struct nvme_dev *dev, int write,

include/uapi/linux/nvme.h

···
 	NVME_SC_REFTAG_CHECK		= 0x284,
 	NVME_SC_COMPARE_FAILED		= 0x285,
 	NVME_SC_ACCESS_DENIED		= 0x286,
+	NVME_SC_DNR			= 0x4000,
 };
 
 struct nvme_completion {