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dmaengine: ioat: disable relaxed ordering before registering the device

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ioat3_dma_probe() disabled PCIe relaxed ordering after calling
dma_async_device_register(), so if an error occurs and the code jumps
to err_disable_interrupts, the function returns with the device still
registered in the core's dma_device_list while the caller frees the
ioatdma_device struct, leaving a dangling registration that anything
walking the device list can dereference after it's been freed.

Move the capability read/write ahead of dma_async_device_register()
instead. Nothing after registration depends on relaxed ordering
already being disabled, and nothing before it depends on the device
being registered, so this is a plain reordering. It also means every
remaining step after registration can't fail, so there's no need to
ever have to unregister the device once registered.

Fixes: 511deae026 ("dmaengine: ioatdma: disable relaxed ordering for ioatdma")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://lore.kernel.org/dmaengine/20260707165906.249F41F000E9@smtp.kernel.org
Acked-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Link: https://lore.kernel.org/dmaengine/20260707165906.249F41F000E9@smtp.kernel.org/T/#u
Link: https://patch.msgid.link/20260902062153.31048-9-logang@deltatee.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Logan Gunthorpe 2026-09-02 00:21:50 -06:00 committed by Vinod Koul
parent 9f744689c4
commit 10d34fbca6
1 changed files with 9 additions and 9 deletions
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18
drivers/dma/ioat/init.c
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@ -1170,15 +1170,6 @@ static int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca)
ioat_chan->reg_base + IOAT_DCACTRL_OFFSET);
}
err = dma_async_device_register(&ioat_dma->dma_dev);
if (err)
goto err_disable_interrupts;
ioat_kobject_add(ioat_dma, &ioat_ktype);
if (dca)
ioat_dma->dca = ioat_dca_init(pdev, ioat_dma->reg_base);
/* disable relaxed ordering */
err = pcie_capability_read_word(pdev, PCI_EXP_DEVCTL, &val16);
if (err) {
@ -1194,6 +1185,15 @@ static int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca)
goto err_disable_interrupts;
}
err = dma_async_device_register(&ioat_dma->dma_dev);
if (err)
goto err_disable_interrupts;
ioat_kobject_add(ioat_dma, &ioat_ktype);
if (dca)
ioat_dma->dca = ioat_dca_init(pdev, ioat_dma->reg_base);
if (ioat_dma->cap & IOAT_CAP_DPS)
writeb(ioat_pending_level + 1,
ioat_dma->reg_base + IOAT_PREFETCH_LIMIT_OFFSET);