Re: [PATCH 2/2] mm: Add kvmalloc_ab_c and kvzalloc_struct

[Matthew Wilcox]

On Wed, Feb 14, 2018 at 01:55:59PM -0600, Christopher Lameter wrote:
> On Wed, 14 Feb 2018, Matthew Wilcox wrote:
> 
> > +#define kvzalloc_struct(p, member, n, gfp)                         \
> > +   (typeof(p))kvzalloc_ab_c(n,                                     \
> > +           sizeof(*(p)->member) + __must_be_array((p)->member),    \
> > +           offsetof(typeof(*(p)), member), gfp)
> > +
> 
> Uppercase like the similar KMEM_CACHE related macros in
> include/linux/slab.h?>

Do you think that would look better in the users?  Compare:

@@ -1284,7 +1284,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct 
vhost_memory __user *m)
                return -EOPNOTSUPP;
        if (mem.nregions > max_mem_regions)
                return -E2BIG;
-       newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), 
GFP_KERNEL);
+       newmem = kvzalloc_struct(newmem, regions, mem.nregions, GFP_KERNEL);
        if (!newmem)
                return -ENOMEM;

@@ -1284,7 +1284,7 @@ static long vhost_set_memory(struct vhost_dev *d, struct 
vhost_memory __user *m)
                return -EOPNOTSUPP;
        if (mem.nregions > max_mem_regions)
                return -E2BIG;
-       newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), 
GFP_KERNEL);
+       newmem = KVZALLOC_STRUCT(newmem, regions, mem.nregions, GFP_KERNEL);
        if (!newmem)
                return -ENOMEM;

Making it look like a function is more pleasing to my eye, but I'll
change it if that's the only thing keeping it from being merged.