>> >> I think we need to get rid of the acpi_in_resume hack >> >> and use system_state != SYSTEM_RUNNING to address this. >> > >> >Well if hacks are OK it'd actually be reliable to do >> > >> > /* comment goes here */ >> > kmalloc(size, irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL); >> > >> >because the irqs_disabled() thing happens for well-defined reasons. >> >Certainly that's better than looking at system_state (and I >> >don't think we >> >leave SYSTEM_RUNNING during suspend/resume anyway). >> >> If system_state != SYSTEM_RUNNING on resume, theen __might_sleep() >> would not have spit out the dump_stack() above. >> >> This is exactly like boot -- we are bringing up the system >> and we need to configure interrupts, which runs AML, >> which calls kmalloc in a variety of ways, all of which call >> __might_sleep. >> >> It seems simplest to have resume admit that it is like boot >> and that the early allocations with interrupts off simply >> must succeed or it is game-off. >> > >No, we shouldn't expand the use of system_state. Code continues to be >merged which uses it. If we also merge code which enhances >its semantics then we're getting into quadratically-increasing >nastiness rather than linearly-increasing. > >Callers should tell callees what to do. Callees shouldn't be >peeking at globals to work out what to do. > >Lacking any other caller-passed indication, it would be much better for >acpi to look at irqs_disabled(). That's effectively a task-local, >cpu-local argument which was passed down to callees. It's hacky - it's >like the PF_foo flags. But it's heaps better than having all >the kernel fight over the state of a global. I didn't propose that kmalloc callers peek at system_state. I proposed that system_state be set properly on resume exactly like it is set on boot -- SYSTEM_RUNNING means we are up with interrupts enabled. Note that this issue is not specific to ACPI, any other code that calls kmalloc during resume will hit __might_sleep(). This is taken care of by system_state in the case of boot and the callers don't know anything about it -- resume is the same case and should work the same way. -Len
