| Message ID | 20181108174856.10811-1-tiny.windzz@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: mmap: remove verify_mm_writelocked() | expand |
On Thu 08-11-18 12:48:56, Yangtao Li wrote: > We should get rid of this function. It no longer serves its purpose.This > is a historical artifact from 2005 where do_brk was called outside of > the core mm.We do have a proper abstraction in vm_brk_flags and that one > does the locking properly.So there is no need to use this function. > > Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> > --- > mm/mmap.c | 16 ---------------- > 1 file changed, 16 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index f7cd9cb966c0..1cee506494d2 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2910,16 +2910,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, > return ret; > } > > -static inline void verify_mm_writelocked(struct mm_struct *mm) > -{ > -#ifdef CONFIG_DEBUG_VM > - if (unlikely(down_read_trylock(&mm->mmap_sem))) { > - WARN_ON(1); > - up_read(&mm->mmap_sem); > - } > -#endif > -} > - > /* > * this is really a simplified "do_mmap". it only handles > * anonymous maps. eventually we may be able to do some > @@ -2946,12 +2936,6 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla > if (error) > return error; > > - /* > - * mm->mmap_sem is required to protect against another thread > - * changing the mappings in case we sleep. > - */ > - verify_mm_writelocked(mm); > - > /* > * Clear old maps. this also does some error checking for us > */ > -- > 2.17.0 >
On Thu, 8 Nov 2018, Yangtao Li wrote: > We should get rid of this function. It no longer serves its purpose.This > is a historical artifact from 2005 where do_brk was called outside of > the core mm.We do have a proper abstraction in vm_brk_flags and that one > does the locking properly.So there is no need to use this function. > > Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Acked-by: David Rientjes <rientjes@google.com>
diff --git a/mm/mmap.c b/mm/mmap.c index f7cd9cb966c0..1cee506494d2 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2910,16 +2910,6 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, return ret; } -static inline void verify_mm_writelocked(struct mm_struct *mm) -{ -#ifdef CONFIG_DEBUG_VM - if (unlikely(down_read_trylock(&mm->mmap_sem))) { - WARN_ON(1); - up_read(&mm->mmap_sem); - } -#endif -} - /* * this is really a simplified "do_mmap". it only handles * anonymous maps. eventually we may be able to do some @@ -2946,12 +2936,6 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla if (error) return error; - /* - * mm->mmap_sem is required to protect against another thread - * changing the mappings in case we sleep. - */ - verify_mm_writelocked(mm); - /* * Clear old maps. this also does some error checking for us */
We should get rid of this function. It no longer serves its purpose.This is a historical artifact from 2005 where do_brk was called outside of the core mm.We do have a proper abstraction in vm_brk_flags and that one does the locking properly.So there is no need to use this function. Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> --- mm/mmap.c | 16 ---------------- 1 file changed, 16 deletions(-)