On Wed, 7 Nov 2007, Jörn Engel wrote: > On Tue, 6 November 2007 17:11:44 -0800, Christoph Lameter wrote: > > > > +void *get_inodes(struct kmem_cache *s, int nr, void **v) > > +{ > > + int i; > > + > > + spin_lock(&inode_lock); > > + for (i = 0; i < nr; i++) { > > + struct inode *inode = v[i]; > > + > > + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) > > + v[i] = NULL; > > + else > > + __iget(inode); > > + } > > + spin_unlock(&inode_lock); > > + return NULL; > > +} > > +EXPORT_SYMBOL(get_inodes); > > What purpose does the return type have?
The pointer is for communication between the get and kick methods. get() can modify kick() behavior by returning a pointer to a data structure or using the pointer to set a flag. F.e. get() may discover that there is an unreclaimable object and set a flag that causes kick to simply undo the refcount increment. get() may build a map for the objects and indicate in the map special treatment. > > +void *fs_get_inodes(struct kmem_cache *s, int nr, void **v, > > + unsigned long offset) > > +{ > > + int i; > > + > > + for (i = 0; i < nr; i++) > > + v[i] += offset; > > + > > + return get_inodes(s, nr, v); > > +} > > +EXPORT_SYMBOL(fs_get_inodes); > > The fact that all pointers get changed makes me a bit uneasy: > struct foo_inode v[20]; > ... > fs_get_inodes(..., v, ...); > ... > v[0].foo_field = bar; > > No warning, but spectacular fireworks. As far as I can remember: The core code always passes pointers to struct inode to the filesystems. The filesystems will then recalculate the pointers to point to the fs ide of an inode. > > +void kick_inodes(struct kmem_cache *s, int nr, void **v, void *private) > > +{ > > + struct inode *inode; > > + int i; > > + int abort = 0; > > + LIST_HEAD(freeable); > > + struct super_block *sb; > > + > > + for (i = 0; i < nr; i++) { > > + inode = v[i]; > > + if (!inode) > > + continue; > > NULL is legal here? Then fs_get_inodes should check for NULL as well > and not add the offset to NULL pointers, I guess. The get() method may have set a pointer to NULL. The fs_get_inodes() is run at a time when all pointers are valid. > > + } > > + > > + /* Invalidate children and dentry */ > > + if (S_ISDIR(inode->i_mode)) { > > + struct dentry *d = d_find_alias(inode); > > + > > + if (d) { > > + d_invalidate(d); > > + dput(d); > > + } > > + } > > + > > + if (inode->i_state & I_DIRTY) > > + write_inode_now(inode, 1); > > Once more the three-bit I_DIRTY is used like a boolean value. I don't > hold it against you, specifically. A general review/cleanup is > necessary for that. Yeah. I'd be glad if someone could take this piece off my hands.