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Commit e35f38bf authored by Philip J Kelleher's avatar Philip J Kelleher Committed by Jens Axboe
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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: default avatarPhilip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 35f47ef1

drivers/block/rsxx/dma.c

+16 −11
Original line number Diff line number Diff line
@@ -223,6 +223,7 @@ 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 (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),
@@ -230,6 +231,7 @@ static void rsxx_free_dma(struct rsxx_dma_ctrl *ctrl, struct rsxx_dma *dma) 
						   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--;



			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++;

drivers/block/rsxx/rsxx_priv.h

+1 −1
Original line number Diff line number Diff line
@@ -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