On Tue, Nov 01, 2022 at 08:18:27PM +0000, Matthew Wilcox (Oracle) wrote:
> Introduce vmap_alloc() to simply get the address space. This allows
> for code sharing in the next patch.
>
> Suggested-by: Uladzislau Rezki <urezki@xxxxxxxxx>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> mm/vmalloc.c | 41 +++++++++++++++++++++++------------------
> 1 file changed, 23 insertions(+), 18 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index ccaa461998f3..dcab1d3cf185 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -2230,6 +2230,27 @@ void vm_unmap_ram(const void *mem, unsigned int count)
> }
> EXPORT_SYMBOL(vm_unmap_ram);
>
> +static void *vmap_alloc(size_t size, int node)
> +{
> + void *mem;
> +
> + if (likely(size <= (VMAP_MAX_ALLOC * PAGE_SIZE))) {
> + mem = vb_alloc(size, GFP_KERNEL);
> + if (IS_ERR(mem))
> + mem = NULL;
> + } else {
> + struct vmap_area *va;
> + va = alloc_vmap_area(size, PAGE_SIZE,
> + VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
> + if (IS_ERR(va))
> + mem = NULL;
> + else
> + mem = (void *)va->va_start;
> + }
> +
> + return mem;
This reads really strange, why not return the ERR_PTR and do:
static void *vmap_alloc(size_t size, int node)
{
if (unlikely(size > VMAP_MAX_ALLOC * PAGE_SIZE)) {
struct vmap_area *va;
va = alloc_vmap_area(size, PAGE_SIZE, VMALLOC_START,
VMALLOC_END, node, GFP_KERNEL);
if (IS_ERR(va))
return ERR_CAST(va);
return (void *)va->va_start;
}
return vb_alloc(size, GFP_KERNEL);
}
> @@ -2247,24 +2268,8 @@ EXPORT_SYMBOL(vm_unmap_ram);
> void *vm_map_ram(struct page **pages, unsigned int count, int node)
> {
> unsigned long size = (unsigned long)count << PAGE_SHIFT;
> + void *mem = vmap_alloc(size, node);
> + unsigned long addr = (unsigned long)mem;
And here we still need the error check anyway, no matter if it is for
NULL or an ERR_PTR.
