rsxx: Disallow discards from being unmapped. (e35f38bf) · Commits · 戴 / test

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>

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

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