a7y18lte-ubports/android_kernel_samsung_a7y18lte
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

sched/core, x86: Make struct thread_info arch specific again

Browse Source 
commit c8061485a0d7569a865a3cc3c63347b0f42b3765 upstream.

The following commit:

  c65eacbe290b ("sched/core: Allow putting thread_info into task_struct")

... made 'struct thread_info' a generic struct with only a
single ::flags member, if CONFIG_THREAD_INFO_IN_TASK_STRUCT=y is
selected.

This change however seems to be quite x86 centric, since at least the
generic preemption code (asm-generic/preempt.h) assumes that struct
thread_info also has a preempt_count member, which apparently was not
true for x86.

We could add a bit more #ifdefs to solve this problem too, but it seems
to be much simpler to make struct thread_info arch specific
again. This also makes the conversion to THREAD_INFO_IN_TASK_STRUCT a
bit easier for architectures that have a couple of arch specific stuff
in their thread_info definition.

The arch specific stuff _could_ be moved to thread_struct. However
keeping them in thread_info makes it easier: accessing thread_info
members is simple, since it is at the beginning of the task_struct,
while the thread_struct is at the end. At least on s390 the offsets
needed to access members of the thread_struct (with task_struct as
base) are too large for various asm instructions.  This is not a
problem when keeping these members within thread_info.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: keescook@chromium.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1476901693-8492-2-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ zhangyi: skip defination of INIT_THREAD_INFO and struct thread_info ]
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heiko Carstens 2016-10-19 19:28:11 +01:00 committed by prashantpaddune
parent 29ef51fe2f
commit 6d082b09db
1 changed files with 0 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
include/linux/thread_info.h
View File

@ -13,17 +13,6 @@
#ifdef CONFIG_THREAD_INFO_IN_TASK
#ifdef CONFIG_THREAD_INFO_IN_TASK
struct thread_info {
u32 flags; /* low level flags */
};
#define INIT_THREAD_INFO(tsk) \
{ \
.flags = 0, \
}
#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
#define current_thread_info() ((struct thread_info *)current)
#endif