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    SubjectRe: [PATCH v11 02/10] iommu/vt-d: Items required for kdump
    On 05/13/15 at 09:45am, Li, ZhenHua wrote:
    > On 05/12/2015 04:17 PM, Dave Young wrote:
    > >On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
    > >>Add context entry functions needed for kdump.
    > >>+/*
    > >>+ * Fix Crashdump failure caused by leftover DMA through a hardware IOMMU
    > >>+ *
    > >>+ * Fixes the crashdump kernel to deal with an active iommu and legacy
    > >>+ * DMA from the (old) panicked kernel in a manner similar to how legacy
    > >>+ * DMA is handled when no hardware iommu was in use by the old kernel --
    > >>+ * allow the legacy DMA to continue into its current buffers.
    > >>+ *
    > >>+ * In the crashdump kernel, this code:
    > >>+ * 1. skips disabling the IOMMU's translating.
    > >>+ * 2. Do not re-enable IOMMU's translating.
    > >>+ * 3. In kdump kernel, use the old root entry table.
    > >>+ * 4. Allocate pages for new context entry, copy data from old context entries
    > >>+ * in the old kernel to the new ones.
    > >>+ *
    > >>+ * In other kinds of kernel, for example, a kernel started by kexec,
    > >>+ * do the same thing as crashdump kernel.
    > >>+ */
    > >>+
    > >>+
    > >
    > >Above comments should come along with the code changes instead of putting it
    > >in this patch.
    > >
    > >BTW, there's one more blank line at the end..
    > Code change is in 00/10, the cover letter.

    I means the real code, not the changelog.

    > And the blank does not matter, I checked the patch with
    > scripts/checkpatch.pl, no warnings, no errors.

    Why add two line breaks if one is enough? Adding such check in checkpatch.pl
    make sense to me actually.

    Thanks
    Dave


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