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>> + >> +    do { >> +        old.data128[1] = ptr->data128[1]; >> +        new->data[2] &= ~DTE_DATA2_INTR_MASK; >> +        new->data[2] |= old.data[2] & (DTE_DATA2_INTR_MASK | >> DTE_DATA2_RESV_MASK); >> +    } while (!try_cmpxchg128(&ptr->data128[1], &old.data128[1], >> new->data128[1])); > > Please note that try_cmpxchg inherently updates &old.data128[1] above on > failure. There is no need to update value again in the loop. > > Please also note that the value from ptr->data128[1] should be read > using READ_ONCE() to prevent compiler from merging, refetching or > reordering the read. Currently, there is no READ_ONCE() implemented for > __int128, so something like the attached patch should be used. Thanks for pointing this out. I will introduce the attached patch separately in this series on your behalf as author/sign-off, and review the current code to properly use the READ_ONCE(). Thanks, Suravee > Based on the above, the loop should be rewritten as: > >     old.data128[1] = READ_ONCE(ptr->data128[1]); >     do { >         new->data[2] &= ~DTE_DATA2_INTR_MASK; >         new->data[2] |= old.data[2] & (DTE_DATA2_INTR_MASK | > DTE_DATA2_RESV_MASK); >     } while (!try_cmpxchg128(&ptr->data128[1], &old.data128[1], > new->data128[1])); > >> +} >> + >> +static void write_dte_lower128(struct dev_table_entry *ptr, struct >> dev_table_entry *new) >> +{ >> +    struct dev_table_entry old = {}; >> + >> +    /* >> +     * Need to preserve DTE[96:106], which can be set by information >> in IVRS table. >> +     * See set_dev_entry_from_acpi(). >> +     */ >> +    new->data[1] |= ptr->data[1] & DTE_FLAG_MASK; >> + >> +    do { >> +        old.data128[0] = ptr->data128[0]; >> +    } while (!try_cmpxchg128(&ptr->data128[0], &old.data128[0], >> new->data128[0])); > > And this one as: > >     old.data128[0] = READ_ONCE(ptr->data128[0]); >     do { >     } while (!try_cmpxchg128(&ptr->data128[0], &old.data128[0], > new->data128[0])); > > Best regards, > Uros.