From 31fecccbd7b2174487a6b7361153b60a4eda6108 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Thu, 22 Nov 2018 17:16:46 +0100 Subject: [PATCH] btrfs: remove redundant csum buffer in btrfs_io_bio The io_bio tracks checksums and has an inline buffer or an allocated one. And there's a third member that points to the right one, but we don't need to use an extra pointer for that. Let btrfs_io_bio::csum point to the right buffer and check that the inline buffer is not accidentally freed. This shrinks struct btrfs_io_bio by 8 bytes. Reviewed-by: Nikolay Borisov Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba --- fs/btrfs/file-item.c | 12 +++++++----- fs/btrfs/volumes.h | 1 - 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index ba74827..1f2d0a6 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -144,7 +144,10 @@ int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, static void btrfs_io_bio_endio_readpage(struct btrfs_io_bio *bio, int err) { - kfree(bio->csum_allocated); + if (bio->csum != bio->csum_inline) { + kfree(bio->csum); + bio->csum = NULL; + } } static blk_status_t __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, @@ -175,13 +178,12 @@ static blk_status_t __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits; if (!dst) { if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) { - btrfs_bio->csum_allocated = kmalloc_array(nblocks, - csum_size, GFP_NOFS); - if (!btrfs_bio->csum_allocated) { + btrfs_bio->csum = kmalloc_array(nblocks, csum_size, + GFP_NOFS); + if (!btrfs_bio->csum) { btrfs_free_path(path); return BLK_STS_RESOURCE; } - btrfs_bio->csum = btrfs_bio->csum_allocated; btrfs_bio->end_io = btrfs_io_bio_endio_readpage; } else { btrfs_bio->csum = btrfs_bio->csum_inline; diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 8b092bb..702c78c 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -274,7 +274,6 @@ struct btrfs_io_bio { u64 logical; u8 *csum; u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE]; - u8 *csum_allocated; btrfs_io_bio_end_io_t *end_io; struct bvec_iter iter; /* -- 2.7.4