Re: [PATCH V4 3/4] ACPI/IORT: Ignore all errors except EPROBE_DEFER
From: Sricharan R <hidden>
Date: 2017-05-22 11:06:06
Also in:
linux-acpi, linux-arch, linux-arm-kernel, linux-arm-msm, linux-iommu, linux-pci, lkml
Hi Lorenzo, On 5/22/2017 4:07 PM, Lorenzo Pieralisi wrote:
Hi Sricharan, On Thu, May 18, 2017 at 08:24:16PM +0530, Sricharan R wrote:quoted
While deferring the probe of IOMMU masters, xlate and add_device callbacks called from iort_iommu_configure can pass back error values like -ENODEV, which means the IOMMU cannot be connected with that master for real reasons. Before the IOMMU probe deferral, all such errors were ignored. Now all those errors are propagated back, killing the master's probe for such errors. Instead ignore all the errors except EPROBE_DEFER, which is the only one of concern and let the master work without IOMMU, thus restoring the old behavior. Fixes: 5a1bb638d567 ("drivers: acpi: Handle IOMMU lookup failure with deferred probing or error") Signed-off-by: Sricharan R <redacted> --- [V4] Added this patch newly. drivers/acpi/arm64/iort.c | 6 ++++++ 1 file changed, 6 insertions(+)diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index c5fecf9..16e101f 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c@@ -782,6 +782,12 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev) if (err) ops = ERR_PTR(err); + /* Ignore all other errors apart from EPROBE_DEFER */ + if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) { + dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops)); + ops = NULL; + } + return ops; }It is getting a bit convoluted. Is not it better to propagate the error back and let acpi_dma_configure() make a decision accordingly ?
ok, I was trying to keep it in same way as DT, where of_dma_configure (here acpi_dma_configure) calls of_iommu_configure(here iort_iommu_configure) which ends up doing the check. So will have to be changed in both places for symmetry.
quoted hunk ↗ jump to hunk
Something like: -- >8 --diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index e39ec7b..3a10d757 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c@@ -1371,8 +1371,8 @@ int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) iort_set_dma_mask(dev); iommu = iort_iommu_configure(dev); - if (IS_ERR(iommu)) - return PTR_ERR(iommu); + if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER) + return -EPROBE_DEFER;
In case of other errors apart from EPROBE_DEFER, iommu = NULL should be set, before passing it on to arch_setup_dma_ops. Regards, Sricharan
size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); /*
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