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get rid of legacy 'get_ds()' function

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Every in-kernel use of this function defined it to KERNEL_DS (either as
an actual define, or as an inline function).  It's an entirely
historical artifact, and long long long ago used to actually read the
segment selector valueof '%ds' on x86.

Which in the kernel is always KERNEL_DS.

Inspired by a patch from Jann Horn that just did this for a very small
subset of users (the ones in fs/), along with Al who suggested a script.
I then just took it to the logical extreme and removed all the remaining
gunk.

Roughly scripted with

   git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/'
   git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d'

plus manual fixups to remove a few unusual usage patterns, the couple of
inline function cases and to fix up a comment that had become stale.

The 'get_ds()' function remains in an x86 kvm selftest, since in user
space it actually does something relevant.

Inspired-by: Jann Horn <jannh@google.com>
Inspired-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2019-03-04 10:39:05 -08:00
parent 84c4e1f89f
commit 736706bee3
33 changed files with 16 additions and 52 deletions
Download patch file Download diff file Expand all files Collapse all files

7
arch/m68k/include/asm/segment.h
View file

@ -45,16 +45,9 @@ static inline void set_fs(mm_segment_t val)
: /* no outputs */ : "r" (val.seg) : "memory");
}
static inline mm_segment_t get_ds(void)
{
/* return the supervisor data space code */
return KERNEL_DS;
}
#else
#define USER_DS MAKE_MM_SEG(TASK_SIZE)
#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#endif