On Fri, 29 Apr 2022 13:22:06 -0700 Mina Almasry <almasrymina@xxxxxxxxxx> wrote:
> After commit db71ef79b59b ("hugetlb: make free_huge_page irq safe"),
> the subpool lock should be locked with spin_lock_irq() and all call
> sites was modified as such, except for the ones in hugetlbfs_statfs().
>
> ...
>
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -1048,12 +1048,12 @@ static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
> if (sbinfo->spool) {
> long free_pages;
>
> - spin_lock(&sbinfo->spool->lock);
> + spin_lock_irq(&sbinfo->spool->lock);
> buf->f_blocks = sbinfo->spool->max_hpages;
> free_pages = sbinfo->spool->max_hpages
> - sbinfo->spool->used_hpages;
> buf->f_bavail = buf->f_bfree = free_pages;
> - spin_unlock(&sbinfo->spool->lock);
> + spin_unlock_irq(&sbinfo->spool->lock);
> buf->f_files = sbinfo->max_inodes;
> buf->f_ffree = sbinfo->free_inodes;
> }
Looks good.
This seems to be theoretically deadlockable and less theoretically
lockdep splattable, so I'm inclined to cc:stable on this.
I wonder why we didn't do that with db71ef79b59bb2e78dc4.
