Re: [akpm-mm:mm-unstable 208/262] lib/maple_tree.c:5506:30: error: 'struct ma_state' has no member named 'end'

[Sidhartha Kumar <sidhartha.kumar@oracle.com>]

On 12/13/23 6:24 AM, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> head:   4d9256c0c56bafd76b8b1517916451e168fae495
> commit: 84bda0b24555d3fdf52b56040696ee1ee00700c9 [208/262] maple_tree: do not preallocate nodes for slot stores
> config: arc-allnoconfig (https://download.01.org/0day-ci/archive/20231213/202312132207.KsGGGt1v-lkp@intel.com/config)
> compiler: arc-elf-gcc (GCC) 13.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231213/202312132207.KsGGGt1v-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202312132207.KsGGGt1v-lkp@intel.com/
> 
> Note: the akpm-mm/mm-unstable HEAD 4d9256c0c56bafd76b8b1517916451e168fae495 builds fine.
>        It only hurts bisectability.
> 
> All errors (new ones prefixed by >>):
> 
>     lib/maple_tree.c: In function 'mas_preallocate':
>>> lib/maple_tree.c:5506:30: error: 'struct ma_state' has no member named 'end'
>      5506 |         if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree))
>           |                              ^~
> 
Hi Andrew,

I developed this patch over mm-unstable which contains the change to make end a 
member of struct ma_state. But because this patch is a hotfix, it shouldn't have 
been developed on top of feature commits that won't be a part of a 6.7 rc. I'll 
send a v2 with the coding style changes and using wr_mas->node_end.

When this fix is merged into mm-unstable, it will cause another build error 
because  Liam's series [PATCH 00/12] maple_tree: iterator state changes[1] will 
have to be updated to converting this patch's use of wr_mas->node.

Thanks,
Sid



[1]: 
https://lore.kernel.org/all/20231101171629.3612299-5-Liam.Howlett@oracle.com/T/#mc0e5000f6de822182bf7579c230030c5ec4ec1a7

> 
> vim +5506 lib/maple_tree.c
> 
>    5465	
>    5466	/**
>    5467	 * mas_preallocate() - Preallocate enough nodes for a store operation
>    5468	 * @mas: The maple state
>    5469	 * @entry: The entry that will be stored
>    5470	 * @gfp: The GFP_FLAGS to use for allocations.
>    5471	 *
>    5472	 * Return: 0 on success, -ENOMEM if memory could not be allocated.
>    5473	 */
>    5474	int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
>    5475	{
>    5476		MA_WR_STATE(wr_mas, mas, entry);
>    5477		unsigned char node_size;
>    5478		int request = 1;
>    5479		int ret;
>    5480	
>    5481	
>    5482		if (unlikely(!mas->index && mas->last == ULONG_MAX))
>    5483			goto ask_now;
>    5484	
>    5485		mas_wr_store_setup(&wr_mas);
>    5486		wr_mas.content = mas_start(mas);
>    5487		/* Root expand */
>    5488		if (unlikely(mas_is_none(mas) || mas_is_ptr(mas)))
>    5489			goto ask_now;
>    5490	
>    5491		if (unlikely(!mas_wr_walk(&wr_mas))) {
>    5492			/* Spanning store, use worst case for now */
>    5493			request = 1 + mas_mt_height(mas) * 3;
>    5494			goto ask_now;
>    5495		}
>    5496	
>    5497		/* At this point, we are at the leaf node that needs to be altered. */
>    5498		/* Exact fit, no nodes needed. */
>    5499		if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last)
>    5500			return 0;
>    5501	
>    5502		mas_wr_end_piv(&wr_mas);
>    5503		node_size = mas_wr_new_end(&wr_mas);
>    5504	
>    5505		/* Slot store, does not require additional nodes */
>> 5506		if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree))
>    5507			|| (wr_mas.offset_end - mas->offset == 1)))
>    5508			return 0;
>    5509	
>    5510		if (node_size >= mt_slots[wr_mas.type]) {
>    5511			/* Split, worst case for now. */
>    5512			request = 1 + mas_mt_height(mas) * 2;
>    5513			goto ask_now;
>    5514		}
>    5515	
>    5516		/* New root needs a singe node */
>    5517		if (unlikely(mte_is_root(mas->node)))
>    5518			goto ask_now;
>    5519	
>    5520		/* Potential spanning rebalance collapsing a node, use worst-case */
>    5521		if (node_size  - 1 <= mt_min_slots[wr_mas.type])
>    5522			request = mas_mt_height(mas) * 2 - 1;
>    5523	
>    5524		/* node store, slot store needs one node */
>    5525	ask_now:
>    5526		mas_node_count_gfp(mas, request, gfp);
>    5527		mas->mas_flags |= MA_STATE_PREALLOC;
>    5528		if (likely(!mas_is_err(mas)))
>    5529			return 0;
>    5530	
>    5531		mas_set_alloc_req(mas, 0);
>    5532		ret = xa_err(mas->node);
>    5533		mas_reset(mas);
>    5534		mas_destroy(mas);
>    5535		mas_reset(mas);
>    5536		return ret;
>    5537	}
>    5538	EXPORT_SYMBOL_GPL(mas_preallocate);
>    5539	
>