linux-kernel - [PATCH 1/2] btrfs: stop parsing crc32c driver name

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Message-ID: <20250613183753.31864-2-ebiggers@kernel.org>
Date: Fri, 13 Jun 2025 11:37:52 -0700
From: Eric Biggers <ebiggers@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: linux-crypto@...r.kernel.org,
	Ard Biesheuvel <ardb@...nel.org>,
	linux-btrfs@...r.kernel.org,
	Alexander Gordeev <agordeev@...ux.ibm.com>,
	Chris Mason <clm@...com>,
	Josef Bacik <josef@...icpanda.com>,
	David Sterba <dsterba@...e.com>
Subject: [PATCH 1/2] btrfs: stop parsing crc32c driver name

From: Eric Biggers <ebiggers@...gle.com>

To determine whether the crc32c implementation is "fast", use
crc32_optimizations() instead of parsing the crypto_shash driver name.
This keeps the code working as intended after the driver name is changed
by the next patch.

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 fs/btrfs/disk-io.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 1beb9458f622a..7bb453b69639c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2024,18 +2024,14 @@ static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info, u16 csum_type)
 		return PTR_ERR(csum_shash);
 	}
 
 	fs_info->csum_shash = csum_shash;
 
-	/*
-	 * Check if the checksum implementation is a fast accelerated one.
-	 * As-is this is a bit of a hack and should be replaced once the csum
-	 * implementations provide that information themselves.
-	 */
+	/* Check if the checksum implementation is a fast accelerated one. */
 	switch (csum_type) {
 	case BTRFS_CSUM_TYPE_CRC32:
-		if (!strstr(crypto_shash_driver_name(csum_shash), "generic"))
+		if (crc32_optimizations() & CRC32C_OPTIMIZATION)
 			set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
 		break;
 	case BTRFS_CSUM_TYPE_XXHASH:
 		set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
 		break;
-- 
2.49.0