Thomas Gleixner <tglx@xxxxxxxxxxxxx> writes: > Jeff, > > On Wed, Jul 21 2021 at 15:48, Jeff Moyer wrote: > > Please write function names with brackets, i.e. sanitize_phys(). OK, will do. >> memtype_reserve takes an address range of the form [start, end). It > > [start, end] Start is inclusive, end is exclusive, so start <= x < end. I used the notation found here: https://en.wikipedia.org/wiki/Interval_(mathematics) If that's too confusing, I can stick to inclusive vs exclusive verbiage. >> then passes the start and end addresses to sanitize_phys, which is meant >> to operate on the inclusive addresses. If end falls at the end of the >> physical address space, sanitize_phys will return 0. This can result in >> drivers failing to load: >> >> [ 10.000087] mpt3sas_cm0: unable to map adapter memory! or resource not found >> [ 10.000334] mpt3sas_cm0: failure at drivers/scsi/mpt3sas/mpt3sas_scsih.c:10597/_scsih_probe()! > > Doesn't this trigger the WARN() right below that offending line? It does. I'll include the warning message in the v2 posting. >> Fix this by passing the inclusive end address to sanitize_phys. >> >> Fixes: 510ee090abc3 ("x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses") >> Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx> >> -- >> It might be worth adding a comment, here. If there are any suggestions >> on what a sane wording would be, I'm all ears. > > See below. > >> diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c >> index 3112ca7786ed..482557905294 100644 >> --- a/arch/x86/mm/pat/memtype.c >> +++ b/arch/x86/mm/pat/memtype.c >> @@ -583,7 +583,7 @@ int memtype_reserve(u64 start, u64 end, enum page_cache_mode req_type, >> int err = 0; >> >> start = sanitize_phys(start); >> - end = sanitize_phys(end); > > /* > * [start, end] is an exclusive address range, but > * sanitize_phys() expects an inclusive end address > */ That works for me (modulo the interval notation), thanks for the suggestion. Thanks! Jeff
