From 0b49ec37a20bc7eb7178105aadaa8d1ecba825f8 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Sun, 8 Feb 2009 20:27:47 -0700 Subject: [PATCH] PCI/MSI: fix msi_mask() shift fix 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 capability. Signed-off-by: Matthew Wilcox Signed-off-by: Hidetoshi Seto Signed-off-by: Jesse Barnes --- 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 44f15ff70c1..baba2eb5367 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) -- 2.41.1