The patch titled
drivers: fix dma_get_required_mask
has been added to the -mm tree. Its filename is
drivers-fix-dma_get_required_mask.patch
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------------------------------------------------------
Subject: drivers: fix dma_get_required_mask
From: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
There's a bug in the current implementation of dma_get_required_mask() where
it ands the returned mask with the current device mask. This rather defeats
the purpose if you're using the call to determine what your mask should be
(since you will at that time have the default DMA_32BIT_MASK). This bug
results in any driver that uses this function *always* getting a 32 bit mask,
which is wrong.
Fix by removing the and with dev->dma_mask.
This is a pretty nasty bug which can cause mysterious slow downs and panics on
>4GB machines (we've just had one on an aic79xx production system).
It probably also needs to be backported as far as it will go.
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/base/platform.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/base/platform.c~drivers-fix-dma_get_required_mask drivers/base/platform.c
--- a/drivers/base/platform.c~drivers-fix-dma_get_required_mask
+++ a/drivers/base/platform.c
@@ -648,7 +648,7 @@ u64 dma_get_required_mask(struct device
high_totalram += high_totalram - 1;
mask = (((u64)high_totalram) << 32) + 0xffffffff;
}
- return mask & *dev->dma_mask;
+ return mask;
}
EXPORT_SYMBOL_GPL(dma_get_required_mask);
#endif
_
Patches currently in -mm which might be from James.Bottomley@xxxxxxxxxxxxxxxxxxxxx are
git-parisc.patch
git-scsi-misc.patch
git-scsi-rc-fixes.patch
scsi-le_add_cpu-conversion.patch
arcmsr-modify-the-type-of-element-of-messageunit_b.patch
scsi-replace-remaining-__function__-occurrences.patch
fusion-replace-remaining-__function__-occurrences.patch
scsi-replace-__inline-with-inline.patch
scsi-stc-make-class-attributes-static.patch
scsi-osstc-make-class-attributes-static.patch
scsi-chc-fix-shadowed-variable-warnings.patch
scsi-chc-fix-shadowed-variable-warnings-checkpatch-fixes.patch
gdth-allocate-sense_buffer-to-prevent-null-pointer-dereference.patch
drivers-fix-dma_get_required_mask.patch
remove-duplicated-unlikely-in-is_err.patch
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