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authorPhilip J Kelleher <pjk1939@linux.vnet.ibm.com>2013-10-18 17:11:46 -0500
committerJens Axboe <axboe@kernel.dk>2013-11-08 09:10:29 -0700
commite35f38bf73b6c9ec9521d9deb94198a419692db5 (patch)
tree4ecd863d83eeb7e9752312f8757f5c6e03f4ea06 /drivers/block/rsxx/dma.c
parent35f47ef1a1f069cd2f346314fb8212bb49571eac (diff)
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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>
Diffstat (limited to 'drivers/block/rsxx/dma.c')
-rw-r--r--drivers/block/rsxx/dma.c27
1 files changed, 16 insertions, 11 deletions
diff --git a/drivers/block/rsxx/dma.c b/drivers/block/rsxx/dma.c
index 4103601ae675..fc88ba3e1bd2 100644
--- 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++;