On 02/13/2016 02:07 AM, Rafael J. Wysocki wrote: > On Fri, Feb 12, 2016 at 6:43 PM, Aleksey Makarov > <aleksey.makarov@xxxxxxxxxx> wrote: >> The function acpi_table_parse() has some problems: >> 1 It can be called only from __init code >> 2 It does not pass any data to the handler >> 3 It just throws out the value returned from the handler > > So why are those problems? 1. We need this function to be non-__init because we need access to some tables at unpredictable time--it may be before or after the init functions are removed. For example, SPCR (Serial Port Console Redirection) table is needed each time a new console is registered. It can be quite early (console_initcall) or when a module is inserted. 2. Having an additional pointer to void is very useful because it allows drivers to pass (local) data to the handler. Without this, we would need to have global data and a mutex as it was done in drivers/acpi/scan.c (vars ape, acpi_probe_count, acpi_probe_lock). 3. Passing the value returned from the callback is less important as it could be modelled by having a (return) field in the data passed to the handler. It is very convenient though. I use these three properties in my next patch of this series. >> These issues are addressed in this patch > > How are they addressed? A new function acpi_table_parse2() has been created that is just the old acpi_table_parse() without __init, taking the handler with additional data pointer and respecting the value returned from the handler. The old acpi_table_parse() was implemented witht this new function. Dropping __init was made possible by the previous patch where the attribute of the function early_acpi_os_unmap_memory() was changed from __init to __ref and by dropping __init from acpi_apic_instance. I understand why this approach is not good and I am going to fix it. Thank you Aleksey Makarov -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
