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Commit 1b21f5b2 authored by Philip J Kelleher's avatar Philip J Kelleher Committed by Jens Axboe
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rsxx: Moving pci_map_page to prevent overflow. 



The pci_map_page function has been moved into our
issued workqueue to prevent an us running out of
mappable addresses on non-HWWD PCIe x8 slots. The
maximum amount that can possible be mapped at one
time now is: 255 dmas X 4 dma channels X 4096 Bytes.

Signed-off-by: default avatarPhilip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e5feab22

drivers/block/rsxx/core.c

+0 −5
Original line number Diff line number Diff line
@@ -749,10 +749,6 @@ static pci_ers_result_t rsxx_slot_reset(struct pci_dev *dev) 


	card->eeh_state = 0;



	st = rsxx_eeh_remap_dmas(card);

	if (st)

		goto failed_remap_dmas;



	spin_lock_irqsave(&card->irq_lock, flags);

	if (card->n_targets & RSXX_MAX_TARGETS)

		rsxx_enable_ier_and_isr(card, CR_INTR_ALL_G);
@@ -779,7 +775,6 @@ static pci_ers_result_t rsxx_slot_reset(struct pci_dev *dev) 
	return PCI_ERS_RESULT_RECOVERED;



failed_hw_buffers_init:

failed_remap_dmas:

	for (i = 0; i < card->n_targets; i++) {

		if (card->ctrl[i].status.buf)

			pci_free_consistent(card->dev,

drivers/block/rsxx/dma.c

+28 −42
Original line number Diff line number Diff line
@@ -397,6 +397,7 @@ static void rsxx_issue_dmas(struct rsxx_dma_ctrl *ctrl) 
	int tag;

	int cmds_pending = 0;

	struct hw_cmd *hw_cmd_buf;

	int dir;



	hw_cmd_buf = ctrl->cmd.buf;
@@ -433,6 +434,28 @@ static void rsxx_issue_dmas(struct rsxx_dma_ctrl *ctrl) 
			continue;

		}



		if (dma->cmd == HW_CMD_BLK_WRITE)

			dir = PCI_DMA_TODEVICE;

		else

			dir = PCI_DMA_FROMDEVICE;



		/*

		 * The function pci_map_page is placed here because we can

		 * only, by design, issue up to 255 commands to the hardware

		 * at one time per DMA channel. So the maximum amount of mapped

		 * memory would be 255 * 4 channels * 4096 Bytes which is less

		 * than 2GB, the limit of a x8 Non-HWWD PCIe slot. This way the

		 * pci_map_page function should never fail because of a

		 * lack of mappable memory.

		 */

		dma->dma_addr = pci_map_page(ctrl->card->dev, dma->page,

				     dma->pg_off, dma->sub_page.cnt << 9, dir);

		if (pci_dma_mapping_error(ctrl->card->dev, dma->dma_addr)) {

			push_tracker(ctrl->trackers, tag);

			rsxx_complete_dma(ctrl, dma, DMA_CANCELLED);

			continue;

		}



		set_tracker_dma(ctrl->trackers, tag, dma);

		hw_cmd_buf[ctrl->cmd.idx].command  = dma->cmd;

		hw_cmd_buf[ctrl->cmd.idx].tag      = tag;
@@ -629,14 +652,6 @@ static int rsxx_queue_dma(struct rsxx_cardinfo *card, 
	if (!dma)

		return -ENOMEM;



	dma->dma_addr = pci_map_page(card->dev, page, pg_off, dma_len,

				     dir ? PCI_DMA_TODEVICE :

				     PCI_DMA_FROMDEVICE);

	if (pci_dma_mapping_error(card->dev, dma->dma_addr)) {

		kmem_cache_free(rsxx_dma_pool, dma);

		return -ENOMEM;

	}



	dma->cmd          = dir ? HW_CMD_BLK_WRITE : HW_CMD_BLK_READ;

	dma->laddr        = laddr;

	dma->sub_page.off = (dma_off >> 9);
@@ -1039,6 +1054,11 @@ int rsxx_eeh_save_issued_dmas(struct rsxx_cardinfo *card) 
			else

				card->ctrl[i].stats.reads_issued--;



			pci_unmap_page(card->dev, dma->dma_addr,

				       get_dma_size(dma),

				       dma->cmd == HW_CMD_BLK_WRITE ?

				       PCI_DMA_TODEVICE :

				       PCI_DMA_FROMDEVICE);

			list_add_tail(&dma->list, &issued_dmas[i]);

			push_tracker(card->ctrl[i].trackers, j);

			cnt++;
@@ -1050,15 +1070,6 @@ int rsxx_eeh_save_issued_dmas(struct rsxx_cardinfo *card) 
		atomic_sub(cnt, &card->ctrl[i].stats.hw_q_depth);

		card->ctrl[i].stats.sw_q_depth += cnt;

		card->ctrl[i].e_cnt = 0;



		list_for_each_entry(dma, &card->ctrl[i].queue, list) {

			if (!pci_dma_mapping_error(card->dev, dma->dma_addr))

				pci_unmap_page(card->dev, dma->dma_addr,

					       get_dma_size(dma),

					       dma->cmd == HW_CMD_BLK_WRITE ?

					       PCI_DMA_TODEVICE :

					       PCI_DMA_FROMDEVICE);

		}

		spin_unlock_bh(&card->ctrl[i].queue_lock);

	}
@@ -1067,31 +1078,6 @@ int rsxx_eeh_save_issued_dmas(struct rsxx_cardinfo *card) 
	return 0;

}



int rsxx_eeh_remap_dmas(struct rsxx_cardinfo *card)

{

	struct rsxx_dma *dma;

	int i;



	for (i = 0; i < card->n_targets; i++) {

		spin_lock_bh(&card->ctrl[i].queue_lock);

		list_for_each_entry(dma, &card->ctrl[i].queue, list) {

			dma->dma_addr = pci_map_page(card->dev, dma->page,

					dma->pg_off, get_dma_size(dma),

					dma->cmd == HW_CMD_BLK_WRITE ?

					PCI_DMA_TODEVICE :

					PCI_DMA_FROMDEVICE);

			if (pci_dma_mapping_error(card->dev, dma->dma_addr)) {

				spin_unlock_bh(&card->ctrl[i].queue_lock);

				kmem_cache_free(rsxx_dma_pool, dma);

				return -ENOMEM;

			}

		}

		spin_unlock_bh(&card->ctrl[i].queue_lock);

	}



	return 0;

}



int rsxx_dma_init(void)

{

	rsxx_dma_pool = KMEM_CACHE(rsxx_dma, SLAB_HWCACHE_ALIGN);