Re: [PATCH] jbd2: get rid of superfluous __GFP_REPEAT

From: Michal Hocko
Date: Mon Nov 09 2015 - 03:16:58 EST

On Sun 08-11-15 00:08:02, Theodore Ts'o wrote:
> On Sat, Nov 07, 2015 at 10:22:55AM +0900, Tetsuo Handa wrote:
> > All jbd2_alloc() callers seem to pass GFP_NOFS. Therefore, use of
> > vmalloc() which implicitly passes GFP_KERNEL | __GFP_HIGHMEM can cause
> > deadlock, can't it? This vmalloc(size) call needs to be replaced with
> > __vmalloc(size, flags).
> jbd2_alloc is only passed in the bh->b_size, which can't be >
> PAGE_SIZE, so the code path that calls vmalloc() should never get
> called. When we conveted jbd2_alloc() to suppor sub-page size
> allocations in commit d2eecb039368, there was an assumption that it
> could be called with a size greater than PAGE_SIZE, but that's
> certaily not true today.

Thanks for the clarification. Then the patch can be simplified even
more then.