On Mon, May 18, 2020 at 11:06:48AM -0700, Jaegeuk Kim wrote:
> On 05/05, Eric Biggers wrote:
> > From: Eric Biggers <ebigg...@google.com>
> >
> > kmalloc() returns kmalloc'ed memory, and kvmalloc() returns either
> > kmalloc'ed or vmalloc'ed memory. But the f2fs wrappers, f2fs_kmalloc()
> > and f2fs_kvmalloc(), both return both kinds of memory.
> >
> > It's redundant to have two functions that do the same thing, and also
> > breaking the standard naming convention is causing bugs since people
> > assume it's safe to kfree() memory allocated by f2fs_kmalloc(). See
> > e.g. the various allocations in fs/f2fs/compress.c.
> >
> > Fix this by making f2fs_kmalloc() just use kmalloc(). And to avoid
> > re-introducing the allocation failures that the vmalloc fallback was
> > intended to fix, convert the largest allocations to use f2fs_kvmalloc().
> >
> > Signed-off-by: Eric Biggers <ebigg...@google.com>
> > ---
> > fs/f2fs/checkpoint.c | 4 ++--
> > fs/f2fs/f2fs.h | 8 +-------
> > fs/f2fs/node.c | 8 ++++----
> > 3 files changed, 7 insertions(+), 13 deletions(-)
> >
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index 97b6378554b406..ac5b47f15f5e77 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -895,8 +895,8 @@ int f2fs_get_valid_checkpoint(struct f2fs_sb_info *sbi)
> > int i;
> > int err;
> >
> > - sbi->ckpt = f2fs_kzalloc(sbi, array_size(blk_size, cp_blks),
> > - GFP_KERNEL);
> > + sbi->ckpt = f2fs_kvzalloc(sbi, array_size(blk_size, cp_blks),
> > + GFP_KERNEL);
> > if (!sbi->ckpt)
> > return -ENOMEM;
> > /*
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index d036a31a97e84e..bc4c5b9b1bf14c 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -2953,18 +2953,12 @@ static inline bool f2fs_may_extent_tree(struct
> > inode *inode)
> > static inline void *f2fs_kmalloc(struct f2fs_sb_info *sbi,
> > size_t size, gfp_t flags)
> > {
> > - void *ret;
> > -
> > if (time_to_inject(sbi, FAULT_KMALLOC)) {
> > f2fs_show_injection_info(sbi, FAULT_KMALLOC);
> > return NULL;
> > }
> >
> > - ret = kmalloc(size, flags);
> > - if (ret)
> > - return ret;
> > -
> > - return kvmalloc(size, flags);
> > + return kmalloc(size, flags);
>
> IIRC, sometimes, we suffered from ENOMEM from kmalloc, as some structures
> depended on the disk capacity. I can't remember exactly which structure tho.
>
I think this patch already addresses that, by changing the large allocations to
use f2fs_kvmalloc().
- Eric
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