On Sat, 14 Nov 2020 13:51:34 +0800 Hui Su <[email protected]> wrote: > inline the shmem_mapping(), and use shmem_mapping() > instead of 'inode->i_mapping->a_ops == &shmem_aops' > in shmem_evict_inode(). > > ... > > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1152,7 +1152,7 @@ static void shmem_evict_inode(struct inode *inode) > struct shmem_inode_info *info = SHMEM_I(inode); > struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); > > - if (inode->i_mapping->a_ops == &shmem_aops) { > + if (shmem_mapping(inode->i_mapping)) { > shmem_unacct_size(info->flags, inode->i_size); > inode->i_size = 0; > shmem_truncate_range(inode, 0, (loff_t)-1); > @@ -2352,7 +2352,7 @@ static struct inode *shmem_get_inode(struct super_block > *sb, const struct inode > return inode; > } > > -bool shmem_mapping(struct address_space *mapping) > +inline bool shmem_mapping(struct address_space *mapping) > { > return mapping->a_ops == &shmem_aops; > }
huh. I'd have expected the inlining in shmem_evict_inode() to not work because the compiler hasn't seen the definition yet. But gcc has evidently become smarter about that. But really, shmem_mapping() isn't worth an out-of-line call from any callsite - it would be best to make it inlined everywhere. - make shmem_aops global - declare shmem_aops in shmem_fs.h - export shmem_aops to modules for drivers/dma-buf/udmabuf.c - include linux/fs.h in shmem_fs.h for address_space_operations (we already include fs.h via swap.h, but we shouldn't depend on that) - make shmem_mapping() a static inline in shmem_fs.h.
