x86, iommu: Add proper dependency sort routine (and sanity check).

We are using a very simple sort routine which sorts the .iommu_table
array in the order of dependencies. Specifically each structure
of iommu_table_entry has a field 'depend' which contains the function
pointer to the IOMMU that MUST be run before us. We sort the array
of structures so that the struct iommu_table_entry with no
'depend' field are first, and then the subsequent ones are the
ones for which the 'depend' function has been already invoked
(in other words, precede us).

Using the kernel's version 'sort', which is a mergeheap is
feasible, but would require making the comparison operator
scan recursivly the array to satisfy the "heapify" process: setting the
levels properly. The end result would much more complex than it should
be an it is just much simpler to utilize this simple sort routine.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
LKML-Reference: <1282845485-8991-4-git-send-email-konrad.wilk@oracle.com>
CC: H. Peter Anvin <hpa@zytor.com>
CC: Fujita Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/x86/include/asm/iommu_table.h b/arch/x86/include/asm/iommu_table.h
index 435176f..2124e3e 100644
--- a/arch/x86/include/asm/iommu_table.h
+++ b/arch/x86/include/asm/iommu_table.h
@@ -92,4 +92,10 @@ struct iommu_table_entry {
 #define IOMMU_INIT(_detect, _depend, _init, _late_init)			\
 	__IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
 
+void sort_iommu_table(struct iommu_table_entry *start,
+		      struct iommu_table_entry *finish);
+
+void check_iommu_entries(struct iommu_table_entry *start,
+			 struct iommu_table_entry *finish);
+
 #endif /* _ASM_X86_IOMMU_TABLE_H */