Messages in this thread Patch in this message | | | Date | Sun, 8 Feb 2009 20:27:47 -0700 | From | Matthew Wilcox <> | Subject | Re: [PATCH] PCI/MSI: fix msi_mask() (rev. 2) |
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On Mon, Feb 09, 2009 at 10:40:55AM +0900, Hidetoshi Seto wrote: > The commit bffac3c593eba1f9da3efd0199e49ea6558a40ce ("PCI MSI: Fix > undefined shift by 32") does:
I think the commit message could be worded somewhat better, and I think I should be credited as the author of the patch. How about this?
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From: Matthew Wilcox <willy@linux.intel.com>
Hidetoshi Seto points out that commit bffac3c593eba1f9da3efd0199e49ea6558a40ce has wrong values in the array. Rather than correct the array, we can just use a bounds check and perform the calculation specified in the comment. As a bonus, this will not run off the end of the array if the device specifies an illegal value in the MSI capcbility.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
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drivers/pci/msi.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 44f15ff..baba2eb 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -103,14 +103,12 @@ static void msix_set_enable(struct pci_dev *dev, int enable) } } -/* - * Essentially, this is ((1 << (1 << x)) - 1), but without the - * undefinedness of a << 32. - */ static inline __attribute_const__ u32 msi_mask(unsigned x) { - static const u32 mask[] = { 1, 2, 4, 0xf, 0xff, 0xffff, 0xffffffff }; - return mask[x]; + /* Don't shift by >= width of type */ + if (x >= 5) + return 0xffffffff; + return (1 << (1 << x)) - 1; } static void msix_flush_writes(struct irq_desc *desc) -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."
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