rsxx: Disallow discards from being unmapped.

This patch fixes a bug in which discards were always
calling pci_unmap_page. Discards should never call the
pci_unmap_page function call because they are never mapped.

This caused a race condition on PowerPC systems when issuing
discards, writes, and reads all at the same time. The
pci_map_page function would eventually map logical address
0 for a read or write. Discards are always assigned a DMA
address of 0 because they are never mapped. So if
pci_map_page mapped address 0 for a DMA and a discard was
"unmapped" then the address would be freed and would cause
an EEH event to occur when Hardware accesses the address.

This was injected/uncovered in commit:
b347f9cf0bc8d42ee95ba1d3837fd93045ab336b

The pci_dma_mapping_error function declares -1 a DMA_ERROR
not 0 like initially thought So before we would never unmap
discards because they were considered NULL.

This patch should fall on top of commit id:
fc1967bb08a6184ed44ef990e1dd4389901b809c

Also, the driver version is being up dated.

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/dma.c b/drivers/block/rsxx/dma.c
index 4103601ae6759d89cdb9fa7922e9fd08fb4351aa..fc88ba3e1bd27835ecf170d5ba321cf8313a6cea 100644 (file)
--- a/drivers/block/rsxx/dma.c
+++ b/drivers/block/rsxx/dma.c
@@ -223,12 +223,14 @@ static void dma_intr_coal_auto_tune(struct rsxx_cardinfo *card)
 /*----------------- RSXX DMA Handling -------------------*/
 static void rsxx_free_dma(struct rsxx_dma_ctrl *ctrl, struct rsxx_dma *dma)
 {
-       if (!pci_dma_mapping_error(ctrl->card->dev, dma->dma_addr)) {
-               pci_unmap_page(ctrl->card->dev, dma->dma_addr,
-                              get_dma_size(dma),
-                              dma->cmd == HW_CMD_BLK_WRITE ?
-                                          PCI_DMA_TODEVICE :
-                                          PCI_DMA_FROMDEVICE);
+       if (dma->cmd != HW_CMD_BLK_DISCARD) {
+               if (!pci_dma_mapping_error(ctrl->card->dev, dma->dma_addr)) {
+                       pci_unmap_page(ctrl->card->dev, dma->dma_addr,
+                                      get_dma_size(dma),
+                                      dma->cmd == HW_CMD_BLK_WRITE ?
+                                                  PCI_DMA_TODEVICE :
+                                                  PCI_DMA_FROMDEVICE);
+               }
        }
 
        kmem_cache_free(rsxx_dma_pool, dma);
@@ -1057,11 +1059,14 @@ 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);
+                       if (dma->cmd != HW_CMD_BLK_DISCARD) {
+                               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++;

diff --git a/drivers/block/rsxx/rsxx_priv.h b/drivers/block/rsxx/rsxx_priv.h
index 913740e53d3179a54bd0ef6006d77f4493f81ad6..23fa05630fef6d5f89736da5c30c108a4c102ee9 100644 (file)
--- a/drivers/block/rsxx/rsxx_priv.h
+++ b/drivers/block/rsxx/rsxx_priv.h
@@ -52,7 +52,7 @@ struct proc_cmd;
 #define RS70_PCI_REV_SUPPORTED 4
 
 #define DRIVER_NAME "rsxx"
-#define DRIVER_VERSION "4.0.1.2498"
+#define DRIVER_VERSION "4.0.2.2510"
 
 /* Block size is 4096 */
 #define RSXX_HW_BLK_SHIFT              12