[PATCH v13 05/12] bcache: bch_nvmpg_free_pages() of the buddy allocator

Coly Li
2021-12-12T17:06:30Z

From: Jianpeng Ma <jianpeng.ma@intel.com>

This patch implements the bch_nvmpg_free_pages() of the buddy allocator.

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>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
---
drivers/md/bcache/nvmpg.c | 164 ++++++++++++++++++++++++++++++++++++--
drivers/md/bcache/nvmpg.h | 3 +
2 files changed, 160 insertions(+), 7 deletions(-)

diff --git a/drivers/md/bcache/nvmpg.c b/drivers/md/bcache/nvmpg.c
index a920779eb548..8ce0c4389b42 100644
--- a/drivers/md/bcache/nvmpg.c
+++ b/drivers/md/bcache/nvmpg.c
@@ -248,6 +248,57 @@ static int init_nvmpg_set_header(struct bch_nvmpg_ns *ns)
return rc;
}

+static void __free_space(struct bch_nvmpg_ns *ns, unsigned long nvmpg_offset,
+ int order)
+{
+ unsigned long add_pages = (1L << order);
+ pgoff_t pgoff;
+ struct page *page;
+ void *va;
+
+ if (nvmpg_offset == 0) {
+ pr_err("free pages on offset 0\n");
+ return;
+ }
+
+ page = bch_nvmpg_va_to_pg(bch_nvmpg_offset_to_ptr(nvmpg_offset));
+ WARN_ON((!page) || (page->private != order));
+ pgoff = page->index;
+
+ while (order < BCH_MAX_ORDER - 1) {
+ struct page *buddy_page;
+
+ pgoff_t buddy_pgoff = pgoff ^ (1L << order);
+ pgoff_t parent_pgoff = pgoff & ~(1L << order);
+
+ if ((parent_pgoff + (1L << (order + 1)) > ns->pages_total))
+ break;
+
+ va = bch_nvmpg_pgoff_to_ptr(ns, buddy_pgoff);
+ buddy_page = bch_nvmpg_va_to_pg(va);
+ 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;
+ }
+
+ va = bch_nvmpg_pgoff_to_ptr(ns, pgoff);
+ page = bch_nvmpg_va_to_pg(va);
+ 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;
+}
+
static void bch_nvmpg_init_free_space(struct bch_nvmpg_ns *ns)
{
unsigned int start, end, pages;
@@ -261,21 +312,19 @@ static void bch_nvmpg_init_free_space(struct bch_nvmpg_ns *ns)
pages = end - start;

while (pages) {
- void *addr;
-
for (i = BCH_MAX_ORDER - 1; i >= 0; i--) {
if ((pgoff_start % (1L << i) == 0) &&
(pages >= (1L << i)))
break;
}

- addr = bch_nvmpg_pgoff_to_ptr(ns, pgoff_start);
- page = bch_nvmpg_va_to_pg(addr);
+ page = bch_nvmpg_va_to_pg(
+ bch_nvmpg_pgoff_to_ptr(ns, pgoff_start));
set_page_private(page, i);
page->index = pgoff_start;
- __SetPageBuddy(page);
- list_add((struct list_head *)&page->zone_device_data,
- &ns->free_area[i]);
+
+ /* In order to update ns->free */
+ __free_space(ns, pgoff_start, i);

pgoff_start += 1L << i;
pages -= 1L << i;
@@ -490,6 +539,106 @@ unsigned long bch_nvmpg_alloc_pages(int order, const char *uuid)
return nvmpg_offset;
}

+static inline void *nvm_end_addr(struct bch_nvmpg_ns *ns)
+{
+ return ns->base_addr + (ns->pages_total << PAGE_SHIFT);
+}
+
+static inline bool in_nvmpg_ns_range(struct bch_nvmpg_ns *ns,
+ void *start_addr, void *end_addr)
+{
+ return (start_addr >= ns->base_addr) && (end_addr < nvm_end_addr(ns));
+}
+
+static int remove_nvmpg_rec(struct bch_nvmpg_recs *recs, int ns_id,
+ unsigned long nvmpg_offset, int order)
+{
+ struct bch_nvmpg_head *head;
+ struct bch_nvmpg_recs *prev_recs, *sys_recs;
+ struct bch_nvmpg_ns *ns;
+ unsigned long pgoff;
+ int i;
+
+ ns = global_nvmpg_set->ns_tbl[0];
+ pgoff = bch_nvmpg_offset_to_pgoff(nvmpg_offset);
+
+ head = bch_nvmpg_offset_to_ptr(recs->head_offset);
+ prev_recs = recs;
+ sys_recs = bch_nvmpg_offset_to_ptr(BCH_NVMPG_SYSRECS_OFFSET);
+ while (recs) {
+ for (i = 0; i < recs->size; i++) {
+ struct bch_nvmpg_rec *rec = &(recs->recs[i]);
+
+ if ((rec->pgoff == pgoff) && (rec->ns_id == ns_id)) {
+ WARN_ON(rec->order != order);
+ rec->_v = 0;
+ recs->used--;
+
+ if (recs->used == 0) {
+ int recs_pos = recs - sys_recs;
+
+ if (recs == prev_recs)
+ head->recs_offset[ns_id] =
+ recs->next_offset;
+ else
+ prev_recs->next_offset =
+ recs->next_offset;
+
+ recs->next_offset = 0;
+ recs->head_offset = 0;
+
+ bitmap_clear(ns->recs_bitmap, recs_pos, 1);
+ }
+ goto out;
+ }
+ }
+ prev_recs = recs;
+ recs = bch_nvmpg_offset_to_ptr(recs->next_offset);
+ }
+out:
+ return (recs ? 0 : -ENOENT);
+}
+
+void bch_nvmpg_free_pages(unsigned long nvmpg_offset, int order,
+ const char *uuid)
+{
+ struct bch_nvmpg_ns *ns;
+ struct bch_nvmpg_head *head;
+ struct bch_nvmpg_recs *recs;
+ int r;
+
+ mutex_lock(&global_nvmpg_set->lock);
+
+ ns = global_nvmpg_set->ns_tbl[BCH_NVMPG_GET_NS_ID(nvmpg_offset)];
+ if (!ns) {
+ pr_err("can't find namespace by given kaddr from namespace\n");
+ goto unlock;
+ }
+
+ head = find_nvmpg_head(uuid, false);
+ if (!head) {
+ pr_err("can't found bch_nvmpg_head by uuid\n");
+ goto unlock;
+ }
+
+ recs = find_nvmpg_recs(ns, head, false);
+ if (!recs) {
+ pr_err("can't find bch_nvmpg_recs by uuid\n");
+ goto unlock;
+ }
+
+ r = remove_nvmpg_rec(recs, ns->sb->this_ns, nvmpg_offset, order);
+ if (r < 0) {
+ pr_err("can't find bch_nvmpg_rec\n");
+ goto unlock;
+ }
+
+ __free_space(ns, nvmpg_offset, order);
+
+unlock:
+ mutex_unlock(&global_nvmpg_set->lock);
+}
+
static int attach_nvmpg_set(struct bch_nvmpg_ns *ns)
{
struct bch_nvmpg_sb *sb = ns->sb;
@@ -686,6 +835,7 @@ struct bch_nvmpg_ns *bch_register_namespace(const char *dev_path)
ns->pages_offset = sb->pages_offset;
ns->pages_total = sb->pages_total;
ns->sb = sb;
+ /* increase by __free_space() */
ns->free = 0;
ns->bdev = bdev;
ns->set = global_nvmpg_set;
diff --git a/drivers/md/bcache/nvmpg.h b/drivers/md/bcache/nvmpg.h
index d03f3241b45a..e089936e7f13 100644
--- a/drivers/md/bcache/nvmpg.h
+++ b/drivers/md/bcache/nvmpg.h
@@ -93,6 +93,7 @@ struct bch_nvmpg_ns *bch_register_namespace(const char *dev_path);
int bch_nvmpg_init(void);
void bch_nvmpg_exit(void);
unsigned long bch_nvmpg_alloc_pages(int order, const char *uuid);
+void bch_nvmpg_free_pages(unsigned long nvmpg_offset, int order, const char *uuid);

#else

@@ -113,6 +114,8 @@ static inline unsigned long bch_nvmpg_alloc_pages(int order, const char *uuid)
return 0;
}

+static inline void bch_nvmpg_free_pages(void *addr, int order, const char *uuid) { }
+
#endif /* CONFIG_BCACHE_NVM_PAGES */

#endif /* _BCACHE_NVM_PAGES_H */
--
2.31.1