Messages in this thread | | | Date | Mon, 5 Feb 2018 17:25:20 +0100 | From | Niklas Cassel <> | Subject | Re: [PATCH 3/3] PCI: designware-ep: Return an error when requesting a too large BAR size |
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On Thu, Feb 01, 2018 at 02:00:40PM -0500, Jingoo Han wrote: > On Thursday, February 1, 2018 1:58 PM, Andy Shevchenko wrote: > > > > On Thu, Feb 1, 2018 at 6:11 PM, Niklas Cassel <niklas.cassel@axis.com> > > wrote: > > > > include/linux/sizes.h: > > > > +SZ_4G 0x100000000ULL > > > > > + if (size > 0x100000000ULL) { > > > > #include <linux/sizes.h> > > > > if (size > SZ_4G) { > > I like this one for the readability. > Thank you. >
I liked it too, however both variants
if (size > 0x100000000ULL) {
if (size > SZ_4G) {
result in:
drivers/pci/dwc/pcie-designware-ep.c:131:11: warning: comparison is always false due to limited range of data type [-Wtype-limits]
when compiling with W=1 on a platform with 32-bit size_t.
The annoying thing here is that a BAR can be 64-bit, yet the parameter size is defined as a size_t, so the error will only show on 32-bit and not on 64-bit.
What do you think about:
if (upper_32_bits(size)) { dev_err(pci->dev, "can't handle BAR larger than 4GB\n"); return -EINVAL; }
That should compile without warnings for both 32-bit size_t and 64-bit size_t.
Regards, Niklas
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