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Subject[PATCH] zpool: add zpool_has_pool()
Date
Add zpool_has_pool() function, indicating if the specified type of zpool
is available (i.e. zsmalloc or zbud). This allows checking if a pool is
available, without actually trying to allocate it, similar to
crypto_has_alg().

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
---
include/linux/zpool.h | 2 ++
mm/zpool.c | 25 +++++++++++++++++++++++++
2 files changed, 27 insertions(+)

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 56529b3..31b79e2 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -36,6 +36,8 @@ enum zpool_mapmode {
ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
};

+bool zpool_has_pool(char *type);
+
struct zpool *zpool_create_pool(char *type, char *name,
gfp_t gfp, struct zpool_ops *ops);

diff --git a/mm/zpool.c b/mm/zpool.c
index 884659d..bff40ce 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -127,6 +127,31 @@ static void zpool_put_driver(struct zpool_driver *driver)
}

/**
+ * zpool_has_pool() - Check if the pool driver is available
+ * @type The type of the zpool to check (e.g. zbud, zsmalloc)
+ *
+ * This checks if the @type pool driver is available.
+ *
+ * Returns: true if @type pool is available, false if not
+ */
+bool zpool_has_pool(char *type)
+{
+ struct zpool_driver *driver = zpool_get_driver(type);
+
+ if (!driver) {
+ request_module("zpool-%s", type);
+ driver = zpool_get_driver(type);
+ }
+
+ if (!driver)
+ return false;
+
+ zpool_put_driver(driver);
+ return true;
+}
+EXPORT_SYMBOL(zpool_has_pool);
+
+/**
* zpool_create_pool() - Create a new zpool
* @type The type of the zpool to create (e.g. zbud, zsmalloc)
* @name The name of the zpool (e.g. zram0, zswap)
--
2.1.0


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