btrfs: advertise which crc32c implementation is being used at module load

Since several architectures support hardware-accelerated crc32c
calculation, it would be nice to confirm that btrfs is actually using it.

We can see an elevated use count for the module, but it doesn't actually
show who the users are.  This patch simply prints the name of the driver
after successfully initializing the shash.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
[ added a helper and used in module load-time message ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
index aae520b2aee535f069946ba332b83a3ab0d44644..a97fdc156a03512bf36df40dd1b4278df845115f 100644 (file)
--- a/fs/btrfs/hash.c
+++ b/fs/btrfs/hash.c
@@ -24,6 +24,11 @@ int __init btrfs_hash_init(void)
        return PTR_ERR_OR_ZERO(tfm);
 }
 
+const char* btrfs_crc32c_impl(void)
+{
+       return crypto_tfm_alg_driver_name(crypto_shash_tfm(tfm));
+}
+
 void btrfs_hash_exit(void)
 {
        crypto_free_shash(tfm);

diff --git a/fs/btrfs/hash.h b/fs/btrfs/hash.h
index 118a2316e5d39f51cc6293e912ed9d2598d6afd8..c3a2ec554361f5d33b4b5a1a6eda29dca5b82aad 100644 (file)
--- a/fs/btrfs/hash.h
+++ b/fs/btrfs/hash.h
@@ -22,6 +22,7 @@
 int __init btrfs_hash_init(void);
 
 void btrfs_hash_exit(void);
+const char* btrfs_crc32c_impl(void);
 
 u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length);
 

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4e59a91a11e0447ab05f5c39b9f5baa58121fc23..4397a303fc6c82a50ac99166c35e0a3972a2f718 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2303,7 +2303,7 @@ static void btrfs_interface_exit(void)
 
 static void btrfs_print_mod_info(void)
 {
-       printk(KERN_INFO "Btrfs loaded"
+       printk(KERN_INFO "Btrfs loaded, crc32c=%s"
 #ifdef CONFIG_BTRFS_DEBUG
                        ", debug=on"
 #endif
@@ -2313,7 +2313,8 @@ static void btrfs_print_mod_info(void)
 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
                        ", integrity-checker=on"
 #endif
-                       "\n");
+                       "\n",
+                       btrfs_crc32c_impl());
 }
 
 static int btrfs_run_sanity_tests(void)