Messages in this thread | | | Date | Mon, 15 Nov 2021 12:57:26 +0100 | From | Krzysztof Wilczyński <> | Subject | Re: [PATCH v2 1/1] PCI: brcmstb: Use BIT() as __GENMASK() is for internal use only |
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Hi Andy,
> Use BIT() as __GENMASK() is for internal use only. The rationale > of switching to BIT() is to provide better generated code. The > GENMASK() against non-constant numbers may produce an ugly assembler > code. On contrary the BIT() is simply converted to corresponding shift > operation. > > Note, it's the only user of __GENMASK() in the kernel outside of its own realm. > > Fixes: 3baec684a531 ("PCI: brcmstb: Accommodate MSI for older chips") > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > v2: switched to BIT() and elaborated why, hence not included tag > drivers/pci/controller/pcie-brcmstb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c > index 1fc7bd49a7ad..0c49fc65792c 100644 > --- a/drivers/pci/controller/pcie-brcmstb.c > +++ b/drivers/pci/controller/pcie-brcmstb.c > @@ -619,7 +619,7 @@ static void brcm_msi_remove(struct brcm_pcie *pcie) > > static void brcm_msi_set_regs(struct brcm_msi *msi) > { > - u32 val = __GENMASK(31, msi->legacy_shift); > + u32 val = ~(BIT(msi->legacy_shift) - 1);
Thank you! I also personally prefer using BIT() macro here.
Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
Krzysztof
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