Re: [PATCH] mm: introduce kv[mz]alloc helpers

From: Vlastimil Babka
Date: Fri Jan 06 2017 - 09:40:22 EST


On 01/04/2017 03:20 PM, Michal Hocko wrote:
> diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
> index 2ff499680cc6..0a5cc1237afe 100644
> --- a/net/netfilter/x_tables.c
> +++ b/net/netfilter/x_tables.c
> @@ -712,17 +712,8 @@ EXPORT_SYMBOL(xt_check_entry_offsets);
> */
> unsigned int *xt_alloc_entry_offsets(unsigned int size)
> {
> - unsigned int *off;
> + return kvmalloc(size * sizeof(unsigned int), GFP_KERNEL);;
>
> - off = kcalloc(size, sizeof(unsigned int), GFP_KERNEL | __GFP_NOWARN);
> -
> - if (off)
> - return off;
> -
> - if (size < (SIZE_MAX / sizeof(unsigned int)))
> - off = vmalloc(size * sizeof(unsigned int));
> -
> - return off;

This one seems to have tried hard to avoid the multiplication overflow
by using kcalloc() and doing the size check before vmalloc(), so I
wonder if it's safe to just remove the checks completely?

> }
> EXPORT_SYMBOL(xt_alloc_entry_offsets);
>
> diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
> index 86309a3156a5..5678eff40f61 100644
> --- a/net/sched/sch_fq.c
> +++ b/net/sched/sch_fq.c
> @@ -624,16 +624,6 @@ static void fq_rehash(struct fq_sched_data *q,
> q->stat_gc_flows += fcnt;
> }
>
> -static void *fq_alloc_node(size_t sz, int node)
> -{
> - void *ptr;
> -
> - ptr = kmalloc_node(sz, GFP_KERNEL | __GFP_REPEAT | __GFP_NOWARN, node);

Another patch 3 material?

> - if (!ptr)
> - ptr = vmalloc_node(sz, node);
> - return ptr;
> -}
> -
> static void fq_free(void *addr)
> {
> kvfree(addr);
> @@ -650,7 +640,7 @@ static int fq_resize(struct Qdisc *sch, u32 log)
> return 0;
>
> /* If XPS was setup, we can allocate memory on right NUMA node */
> - array = fq_alloc_node(sizeof(struct rb_root) << log,
> + array = kvmalloc_node(sizeof(struct rb_root) << log, GFP_KERNEL,
> netdev_queue_numa_node_read(sch->dev_queue));
> if (!array)
> return -ENOMEM;

With that fixed,

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>