[PATCH v12 06/12] bcache: get recs list head for allocated pages by specific uuid

[Coly Li <colyli@xxxxxxx>]

From: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>

This patch implements bch_get_nvmpg_head() of the buddy allocator
to be used to get recs list head for allocated pages by specific
uuid. Then the requester (owner) can find all previous allocated
nvdimm pages by iterating the recs list.

Signed-off-by: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
Co-developed-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
Signed-off-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
---
 drivers/md/bcache/nvm-pages.c | 6 ++++++
 drivers/md/bcache/nvm-pages.h | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/md/bcache/nvm-pages.c b/drivers/md/bcache/nvm-pages.c
index ef61fdaaac28..497360c60f26 100644
--- a/drivers/md/bcache/nvm-pages.c
+++ b/drivers/md/bcache/nvm-pages.c
@@ -523,6 +523,12 @@ void *bch_nvmpg_alloc_pages(int order, const char *uuid)
 }
 EXPORT_SYMBOL_GPL(bch_nvmpg_alloc_pages);
 
+struct bch_nvmpg_head *bch_get_nvmpg_head(const char *uuid)
+{
+	return find_nvmpg_head(uuid, false);
+}
+EXPORT_SYMBOL_GPL(bch_get_nvmpg_head);
+
 static inline void *nvm_end_addr(struct bch_nvmpg_ns *ns)
 {
 	return ns->base_addr + (ns->pages_total << PAGE_SHIFT);
diff --git a/drivers/md/bcache/nvm-pages.h b/drivers/md/bcache/nvm-pages.h
index 2529dc8b9d49..2f6f2ffbfd80 100644
--- a/drivers/md/bcache/nvm-pages.h
+++ b/drivers/md/bcache/nvm-pages.h
@@ -93,6 +93,7 @@ int bch_nvmpg_init(void);
 void bch_nvmpg_exit(void);
 void *bch_nvmpg_alloc_pages(int order, const char *uuid);
 void bch_nvmpg_free_pages(void *addr, int order, const char *uuid);
+struct bch_nvmpg_head *bch_get_nvmpg_head(const char *uuid);
 
 #else
 
@@ -115,6 +116,11 @@ static inline void *bch_nvmpg_alloc_pages(int order, const char *uuid)
 
 static inline void bch_nvmpg_free_pages(void *addr, int order, const char *uuid) { }
 
+static inline struct bch_nvmpg_head *bch_get_nvmpg_head(const char *uuid)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_BCACHE_NVM_PAGES */
 
 #endif /* _BCACHE_NVM_PAGES_H */
-- 
2.26.2