The patch titled
     Subject: lib/iommu-common.c: do not try to deref a null 
iommu->lazy_flush() pointer when n < pool->hint
has been removed from the -mm tree.  Its filename was
     
iommu-common-do-not-try-to-deref-a-null-iommu-lazy_flush-pointer-when-n-pool-hint.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Sowmini Varadhan <[email protected]>
Subject: lib/iommu-common.c: do not try to deref a null iommu->lazy_flush() 
pointer when n < pool->hint

The check for invoking iommu->lazy_flush() from iommu_tbl_range_alloc()
has to be refactored so that we only call ->lazy_flush() if it is
non-null.

I had a sparc kernel that was crashing when I was trying to process
some very large perf.data files- the crash happens when the scsi
driver calls into dma_4v_map_sg and thus the iommu_tbl_range_alloc().

Signed-off-by: Sowmini Varadhan <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 lib/iommu-common.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff -puN 
lib/iommu-common.c~iommu-common-do-not-try-to-deref-a-null-iommu-lazy_flush-pointer-when-n-pool-hint
 lib/iommu-common.c
--- 
a/lib/iommu-common.c~iommu-common-do-not-try-to-deref-a-null-iommu-lazy_flush-pointer-when-n-pool-hint
+++ a/lib/iommu-common.c
@@ -21,8 +21,7 @@ static        DEFINE_PER_CPU(unsigned int, iomm
 
 static inline bool need_flush(struct iommu_map_table *iommu)
 {
-       return (iommu->lazy_flush != NULL &&
-               (iommu->flags & IOMMU_NEED_FLUSH) != 0);
+       return ((iommu->flags & IOMMU_NEED_FLUSH) != 0);
 }
 
 static inline void set_flush(struct iommu_map_table *iommu)
@@ -211,7 +210,8 @@ unsigned long iommu_tbl_range_alloc(stru
                        goto bail;
                }
        }
-       if (n < pool->hint || need_flush(iommu)) {
+       if (iommu->lazy_flush &&
+           (n < pool->hint || need_flush(iommu))) {
                clear_flush(iommu);
                iommu->lazy_flush(iommu);
        }
_

Patches currently in -mm which might be from [email protected] are


--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to