On 6/15/21 7:49 AM, Coly Li wrote:

Please, don't name is 'heads'. If this is supposed to be a linked list,
use the standard list implementation and initialize the pointers correctly.
If it isn't use an array (as you know in advance how many array entries
you can allocate).

+	if (!owner_head && create) {
+		u32 used = only_set->owner_list_used;
+
+		if (only_set->owner_list_size > used) {
+			memcpy_flushcache(owner_list_head->heads[used].uuid, owner_uuid, 16);
+			only_set->owner_list_used++;
+
+			owner_list_head->used++;
+			owner_head = &(owner_list_head->heads[used]);
+		} else
+			pr_info("no free bch_nvm_pages_owner_head\n");
+	}
+
+out:
+	return owner_head;
+}
+
+static struct bch_nvm_pgalloc_recs *find_empty_pgalloc_recs(void)
+{
+	unsigned int start;
+	struct bch_nvm_namespace *ns = only_set->nss[0];
+	struct bch_nvm_pgalloc_recs *recs;
+
+	start = bitmap_find_next_zero_area(ns->pgalloc_recs_bitmap, BCH_MAX_PGALLOC_RECS, 0, 1, 0);
+	if (start > BCH_MAX_PGALLOC_RECS) {
+		pr_info("no free struct bch_nvm_pgalloc_recs\n");
+		return NULL;
+	}
+
+	bitmap_set(ns->pgalloc_recs_bitmap, start, 1);
+	recs = (struct bch_nvm_pgalloc_recs *)(ns->kaddr + BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET)
+		+ start;
+	return recs;
+}
+
+static struct bch_nvm_pgalloc_recs *find_nvm_pgalloc_recs(struct bch_nvm_namespace *ns,
+		struct bch_nvm_pages_owner_head *owner_head, bool create)
+{
+	int ns_nr = ns->sb->this_namespace_nr;
+	struct bch_nvm_pgalloc_recs *prev_recs = NULL, *recs = owner_head->recs[ns_nr];
+
+	/* If create=false, we return recs[nr] */
+	if (!create)
+		return recs;
+
+	/*
+	 * If create=true, it mean we need a empty struct bch_pgalloc_rec
+	 * So we should find non-empty struct bch_nvm_pgalloc_recs or alloc
+	 * new struct bch_nvm_pgalloc_recs. And return this bch_nvm_pgalloc_recs
+	 */
+	while (recs && (recs->used == recs->size)) {
+		prev_recs = recs;
+		recs = recs->next;
+	}
+
+	/* Found empty struct bch_nvm_pgalloc_recs */
+	if (recs)
+		return recs;
+	/* Need alloc new struct bch_nvm_galloc_recs */
+	recs = find_empty_pgalloc_recs();
+	if (recs) {
+		recs->next = NULL;
+		recs->owner = owner_head;
+		memcpy_flushcache(recs->magic, bch_nvm_pages_pgalloc_magic, 16);
+		memcpy_flushcache(recs->owner_uuid, owner_head->uuid, 16);
+		recs->size = BCH_MAX_RECS;
+		recs->used = 0;
+
+		if (prev_recs)
+			prev_recs->next = recs;
+		else
+			owner_head->recs[ns_nr] = recs;
+	}
+

Wouldn't it be easier if the bitmap covers the entire range, and not
just the non-empty ones?
Eventually (ie if the NVM set becomes full) it'll cover it anyway, so
can't we save ourselves some time to allocate a large enough bitmap
upfront and only use it do figure out empty recs?

+	return recs;
+}
+
+static void add_pgalloc_rec(struct bch_nvm_pgalloc_recs *recs, void *kaddr, int order)
+{
+	int i;
+
+	for (i = 0; i < recs->size; i++) {
+		if (recs->recs[i].pgoff == 0) {
+			recs->recs[i].pgoff = (unsigned long)kaddr >> PAGE_SHIFT;
+			recs->recs[i].order = order;
+			recs->used++;
+			break;
+		}
+	}
+	BUG_ON(i == recs->size);
+}
+
+void *bch_nvm_alloc_pages(int order, const char *owner_uuid)
+{
+	void *kaddr = NULL;
+	struct bch_nvm_pgalloc_recs *pgalloc_recs;
+	struct bch_nvm_pages_owner_head *owner_head;
+	int i, j;
+
+	mutex_lock(&only_set->lock);
+	owner_head = find_owner_head(owner_uuid, true);
+
+	if (!owner_head) {
+		pr_err("can't find bch_nvm_pgalloc_recs by(uuid=%s)\n", owner_uuid);
+		goto unlock;
+	}
+
+	for (j = 0; j < only_set->total_namespaces_nr; j++) {
+		struct bch_nvm_namespace *ns = only_set->nss[j];
+
+		if (!ns || (ns->free < (1L << order)))
+			continue;
+
+		for (i = order; i < BCH_MAX_ORDER; i++) {
+			struct list_head *list;
+			struct page *page, *buddy_page;
+
+			if (list_empty(&ns->free_area[i]))
+				continue;
+
+			list = ns->free_area[i].next;

list_first_entry()?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
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