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: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/rsxx/core.c b/drivers/block/rsxx/core.c
index e740a65..a8de2ee 100644 (file)
--- a/drivers/block/rsxx/core.c
+++ b/drivers/block/rsxx/core.c
@@ -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,

diff --git a/drivers/block/rsxx/dma.c b/drivers/block/rsxx/dma.c
index 71d1ca2..34fd101 100644 (file)
--- a/drivers/block/rsxx/dma.c
+++ b/drivers/block/rsxx/dma.c
@@ -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);