Re: [bch-nvm-pages v9 5/6] bcache: bch_nvm_free_pages() of the buddy

[Coly Li <colyli@suse.de>]

On 4/29/21 5:39 AM, Qiaowei Ren wrote:
> From: Jianpeng Ma <jianpeng.ma@intel.com>
> 
> This patch implements the bch_nvm_free_pages() of the buddy.
> 
> The difference between this and page-buddy-free:
> it need owner_uuid to free owner allocated pages.And must
> persistent after free.
> 
> Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com>
> Co-developed-by: Qiaowei Ren <qiaowei.ren@intel.com>
> Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
> [colyli: fix typo in commit log]
> Signed-off-by: Coly Li <colyli@suse.de>
> ---
>  drivers/md/bcache/nvm-pages.c | 164 ++++++++++++++++++++++++++++++++--
>  drivers/md/bcache/nvm-pages.h |   3 +-
>  2 files changed, 159 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/md/bcache/nvm-pages.c b/drivers/md/bcache/nvm-pages.c
> index 2647ff997fab..39807046ecce 100644
> --- a/drivers/md/bcache/nvm-pages.c
> +++ b/drivers/md/bcache/nvm-pages.c
> @@ -52,7 +52,7 @@ static void release_nvm_set(struct bch_nvm_set *nvm_set)
>  	kfree(nvm_set);
>  }
>  
> -static struct page *nvm_vaddr_to_page(struct bch_nvm_namespace *ns, void *addr)
> +static struct page *nvm_vaddr_to_page(void *addr)
>  {
>  	return virt_to_page(addr);
>  }
> @@ -175,6 +175,155 @@ static void add_pgalloc_rec(struct bch_nvm_pgalloc_recs *recs, void *kaddr, int
>  	BUG_ON(i == recs->size);
>  }
>  
> +static inline void *nvm_end_addr(struct bch_nvm_namespace *ns)
> +{
> +	return ns->kaddr + (ns->pages_total << PAGE_SHIFT);
> +}
> +
> +static inline bool in_nvm_range(struct bch_nvm_namespace *ns,
> +		void *start_addr, void *end_addr)
> +{
> +	return (start_addr >= ns->kaddr) && (end_addr <= nvm_end_addr(ns));


Maybe it should be
return (start_addr >= ns->kaddr) && (end_addr < nvm_end_addr(ns)) ?


> +}
> +
> +static struct bch_nvm_namespace *find_nvm_by_addr(void *addr, int order)
> +{
> +	int i;
> +	struct bch_nvm_namespace *ns;
> +
> +	for (i = 0; i < only_set->total_namespaces_nr; i++) {
> +		ns = only_set->nss[i];
> +		if (ns && in_nvm_range(ns, addr, addr + (1 << order)))
> +			return ns;
> +	}
> +	return NULL;
> +}
> +
> +static int remove_pgalloc_rec(struct bch_nvm_pgalloc_recs *pgalloc_recs, int ns_nr,
> +				void *kaddr, int order)
> +{
> +	struct bch_nvm_pages_owner_head *owner_head = pgalloc_recs->owner;
> +	struct bch_nvm_pgalloc_recs *prev_recs, *sys_recs;
> +	u64 pgoff = (unsigned long)kaddr >> PAGE_SHIFT;
> +	struct bch_nvm_namespace *ns = only_set->nss[0];
> +	int i;
> +
> +	prev_recs = pgalloc_recs;
> +	sys_recs = ns->kaddr + BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET;
> +	while (pgalloc_recs) {
> +		for (i = 0; i < pgalloc_recs->size; i++) {
> +			struct bch_pgalloc_rec *rec = &(pgalloc_recs->recs[i]);
> +
> +			if (rec->pgoff == pgoff) {
> +				WARN_ON(rec->order != order);
> +				rec->pgoff = 0;
> +				rec->order = 0;
> +				pgalloc_recs->used--;
> +
> +				if (pgalloc_recs->used == 0) {
> +					int recs_pos = pgalloc_recs - sys_recs;
> +
> +					if (pgalloc_recs == prev_recs)
> +						owner_head->recs[ns_nr] = pgalloc_recs->next;
> +					else
> +						prev_recs->next = pgalloc_recs->next;
> +
> +					pgalloc_recs->next = NULL;
> +					pgalloc_recs->owner = NULL;
> +
> +					bitmap_clear(ns->pgalloc_recs_bitmap, recs_pos, 1);
> +				}
> +				goto exit;
> +			}
> +		}
> +		prev_recs = pgalloc_recs;
> +		pgalloc_recs = pgalloc_recs->next;
> +	}
> +exit:
> +	return pgalloc_recs ? 0 : -ENOENT;
> +}
> +
> +static void __free_space(struct bch_nvm_namespace *ns, void *addr, int order)
> +{
> +	unsigned int add_pages = (1 << order);
> +	pgoff_t pgoff;
> +	struct page *page;
> +
> +	page = nvm_vaddr_to_page(addr);
> +	WARN_ON((!page) || (page->private != order));
> +	pgoff = page->index;
> +
> +	while (order < BCH_MAX_ORDER - 1) {
> +		struct page *buddy_page;
> +
> +		pgoff_t buddy_pgoff = pgoff ^ (1 << order);
> +		pgoff_t parent_pgoff = pgoff & ~(1 << order);
> +
> +		if ((parent_pgoff + (1 << (order + 1)) > ns->pages_total))
> +			break;
> +
> +		buddy_page = nvm_vaddr_to_page(nvm_pgoff_to_vaddr(ns, buddy_pgoff));
> +		WARN_ON(!buddy_page);
> +
> +		if (PageBuddy(buddy_page) && (buddy_page->private == order)) {
> +			list_del((struct list_head *)&buddy_page->zone_device_data);
> +			__ClearPageBuddy(buddy_page);
> +			pgoff = parent_pgoff;
> +			order++;
> +			continue;
> +		}
> +		break;
> +	}
> +
> +	page = nvm_vaddr_to_page(nvm_pgoff_to_vaddr(ns, pgoff));
> +	WARN_ON(!page);
> +	list_add((struct list_head *)&page->zone_device_data, &ns->free_area[order]);
> +	page->index = pgoff;
> +	set_page_private(page, order);
> +	__SetPageBuddy(page);
> +	ns->free += add_pages;
> +}
> +
> +void bch_nvm_free_pages(void *addr, int order, const char *owner_uuid)
> +{
> +	struct bch_nvm_namespace *ns;
> +	struct bch_nvm_pages_owner_head *owner_head;
> +	struct bch_nvm_pgalloc_recs *pgalloc_recs;
> +	int r;
> +
> +	mutex_lock(&only_set->lock);
> +
> +	ns = find_nvm_by_addr(addr, order);
> +	if (!ns) {
> +		pr_info("can't find nvm_dev by kaddr %p\n", addr);

Let's use pr_err() for this error condition.

> +		goto unlock;
> +	}
> +
> +	owner_head = find_owner_head(owner_uuid, false);
> +	if (!owner_head) {
> +		pr_info("can't found bch_nvm_pages_owner_head by(uuid=%s)\n", owner_uuid);

Let's use pr_err() for this error condition.

> +		goto unlock;
> +	}
> +
> +	pgalloc_recs = find_nvm_pgalloc_recs(ns, owner_head, false);
> +	if (!pgalloc_recs) {
> +		pr_info("can't find bch_nvm_pgalloc_recs by(uuid=%s)\n", owner_uuid);

Let's use pr_err() for this error condition.

> +		goto unlock;
> +	}
> +
> +	r = remove_pgalloc_rec(pgalloc_recs, ns->sb->this_namespace_nr, addr, order);
> +	if (r < 0) {
> +		pr_info("can't find bch_pgalloc_rec\n");

Let's use pr_err() for this error condition.

> +		goto unlock;
> +	}
> +
> +	__free_space(ns, addr, order);
> +
> +unlock:
> +	mutex_unlock(&only_set->lock);
> +}
> +EXPORT_SYMBOL_GPL(bch_nvm_free_pages);
> +
>  void *bch_nvm_alloc_pages(int order, const char *owner_uuid)
>  {
>  	void *kaddr = NULL;
> @@ -209,7 +358,7 @@ void *bch_nvm_alloc_pages(int order, const char *owner_uuid)
>  			list_del(list);
>  
>  			while (i != order) {
> -				buddy_page = nvm_vaddr_to_page(ns,
> +				buddy_page = nvm_vaddr_to_page(
>  					nvm_pgoff_to_vaddr(ns, page->index + (1 << (i - 1))));
>  				set_page_private(buddy_page, i - 1);
>  				buddy_page->index = page->index + (1 << (i - 1));
> @@ -291,7 +440,7 @@ static int init_owner_info(struct bch_nvm_namespace *ns)
>  						BUG_ON(rec->pgoff <= offset);
>  
>  						/* init struct page: index/private */
> -						page = nvm_vaddr_to_page(ns,
> +						page = nvm_vaddr_to_page(
>  							BCH_PGOFF_TO_KVADDR(rec->pgoff));
>  
>  						set_page_private(page, rec->order);
> @@ -330,11 +479,12 @@ static void init_nvm_free_space(struct bch_nvm_namespace *ns)
>  					break;
>  			}
>  
> -			page = nvm_vaddr_to_page(ns, nvm_pgoff_to_vaddr(ns, pgoff_start));
> +			page = nvm_vaddr_to_page(nvm_pgoff_to_vaddr(ns, pgoff_start));
>  			page->index = pgoff_start;
>  			set_page_private(page, i);
> -			__SetPageBuddy(page);
> -			list_add((struct list_head *)&page->zone_device_data, &ns->free_area[i]);
> +
> +			/* in order to update ns->free */
> +			__free_space(ns, nvm_pgoff_to_vaddr(ns, pgoff_start), i);
>  
>  			pgoff_start += 1 << i;
>  			pages -= 1 << i;
> @@ -515,7 +665,7 @@ struct bch_nvm_namespace *bch_register_namespace(const char *dev_path)
>  	ns->page_size = ns->sb->page_size;
>  	ns->pages_offset = ns->sb->pages_offset;
>  	ns->pages_total = ns->sb->pages_total;
> -	ns->free = 0;
> +	ns->free = 0; /* increase by __free_space() */
>  	ns->bdev = bdev;
>  	ns->nvm_set = only_set;
>  	mutex_init(&ns->lock);
> diff --git a/drivers/md/bcache/nvm-pages.h b/drivers/md/bcache/nvm-pages.h
> index 4fd5205146a2..918aee6a9afc 100644
> --- a/drivers/md/bcache/nvm-pages.h
> +++ b/drivers/md/bcache/nvm-pages.h
> @@ -63,6 +63,7 @@ struct bch_nvm_namespace *bch_register_namespace(const char *dev_path);
>  int bch_nvm_init(void);
>  void bch_nvm_exit(void);
>  void *bch_nvm_alloc_pages(int order, const char *owner_uuid);
> +void bch_nvm_free_pages(void *addr, int order, const char *owner_uuid);
>  
>  #else
>  
> @@ -79,7 +80,7 @@ static inline void *bch_nvm_alloc_pages(int order, const char *owner_uuid)
>  {
>  	return NULL;
>  }
> -
> +static inline void bch_nvm_free_pages(void *addr, int order, const char *owner_uuid) { }
>  
>  #endif /* CONFIG_BCACHE_NVM_PAGES */
>  
> 

The rested are fine to me. Thanks for the great work :-)

Coly Li