On 05/12/2015 04:17 PM, Dave Young wrote:
On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:Code change is in 00/10, the cover letter.
Add context entry functions needed for kdump.
+ * Fix Crashdump failure caused by leftover DMA through a hardware
+ * 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
+ * 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
+ * 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
in this patch.
BTW, there's one more blank line at the end..
And the blank does not matter, I checked the patch with
scripts/checkpatch.pl, no warnings, no errors.