Re: [PATCH 0/7] Remove unused /dev/oldmem interface

[ebiederm@xmission.com (Eric W. Biederman)]

Zhang Yanfei <zhangyanfei.yes@gmail.com> writes:

> /dev/oldmem provides the interface for us to access the "old memory" in
> the dump-capture kernel. Unfortunately, no one actually uses this interface.
>
> And this interface could actually cause some real problems if used on ia64
> where the cached/uncached accesses are mixed. See the discussion from
> the link: https://lkml.org/lkml/2013/4/12/386.
>
> So Eric suggested that we should remove /dev/oldmem as an unused piece of
> code.
>
> Besides, we used a global variable saved_max_pfn to let the capture kernel
> know the amount of memory that the previous kernel used. And for almost all
> architectures (except x86. In x86, saved_max_pfn is used by detect_calgary()),
> the only user of this variable is the read_oldmem interface of /dev/oldmem, so
> also remove the setting for saved_max_pfn in those architectures.

Except for the devices.txt update.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>

> Zhang Yanfei (7):
>   /dev/oldmem: Remove this interface
>   Documentation/devices.txt: Remove /dev/oldmem description
>   Documentation/kdump/kdump.txt: Remove /dev/oldmem description
>   mips: Remove savemaxmem parameter setup
>   powerpc: Remove savemaxmem parameter setup
>   ia64: Remove setting for saved_max_pfn
>   s390: Remove setting for saved_max_pfn
>
>  Documentation/devices.txt        |    2 -
>  Documentation/kdump/kdump.txt    |   31 +++++--------------------
>  arch/ia64/kernel/efi.c           |    5 ----
>  arch/mips/kernel/crash_dump.c    |   10 --------
>  arch/powerpc/kernel/crash_dump.c |   10 --------
>  arch/s390/kernel/setup.c         |    4 ---
>  drivers/char/mem.c               |   47 --------------------------------------
>  7 files changed, 6 insertions(+), 103 deletions(-)