btrfs: use a shared helper to calculate data checksum for a bio

Since we are already calculating data checksum using bio interface,
extract the generation part into btrfs_csum_one_bio_block(), and use that
to replace the paddrs[] array based solution in csum_one_bio().

This will reduce 128 bytes on-stack memory usage for csum_one_bio().

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 171f96bdb8aa76110df3eb52f81a4b013bcdb424..e137a99151bd070dc3a67724c16006aad86d80d0 100644 (file)
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -515,6 +515,8 @@ int btrfs_check_block_csum(struct btrfs_fs_info *fs_info, phys_addr_t paddr, u8
                           const u8 * const csum_expected);
 bool btrfs_bio_data_csum_ok(struct btrfs_bio *bbio, const struct bvec_iter *orig_iter,
                            struct btrfs_device *dev);
+void btrfs_csum_one_bio_block(struct btrfs_fs_info *fs_info, struct bio *bio,
+                             const struct bvec_iter *orig_iter, u8 *csum);
 noinline int can_nocow_extent(struct btrfs_inode *inode, u64 offset, u64 *len,
                              struct btrfs_file_extent *file_extent,
                              bool nowait);

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index cf50fd623f41a8013fc3a70c76fb93ee20a893a9..581ca5653be93af866ea78caf6b50802b03993eb 100644 (file)
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -801,25 +801,16 @@ static void csum_one_bio(struct btrfs_bio *bbio, struct bvec_iter *src)
 {
        struct btrfs_inode *inode = bbio->inode;
        struct btrfs_fs_info *fs_info = inode->root->fs_info;
-       struct bio *bio = &bbio->bio;
        struct btrfs_ordered_sum *sums = bbio->sums;
-       struct bvec_iter iter = *src;
-       phys_addr_t paddr;
+       struct bvec_iter iter;
        const u32 blocksize = fs_info->sectorsize;
-       const u32 step = min(blocksize, PAGE_SIZE);
-       const u32 nr_steps = blocksize / step;
-       phys_addr_t paddrs[BTRFS_MAX_BLOCKSIZE / PAGE_SIZE];
-       u32 offset = 0;
        int index = 0;
 
-       btrfs_bio_for_each_block(paddr, bio, &iter, step) {
-               paddrs[(offset / step) % nr_steps] = paddr;
-               offset += step;
+       for (iter = *src; iter.bi_size; bio_advance_iter(&bbio->bio, &iter, blocksize)) {
+               btrfs_csum_one_bio_block(fs_info, &bbio->bio, &iter,
+                                        sums->sums + index);
 
-               if (IS_ALIGNED(offset, blocksize)) {
-                       btrfs_calculate_block_csum_pages(fs_info, paddrs, sums->sums + index);
-                       index += fs_info->csum_size;
-               }
+               index += fs_info->csum_size;
        }
 }
 

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 005f8f9da8b139f34428685f015e82bee598e316..11f8aad8601f509b1db0b1a7423fc37c83fd97a7 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3531,6 +3531,32 @@ int btrfs_check_block_csum(struct btrfs_fs_info *fs_info, phys_addr_t paddr, u8
        return 0;
 }
 
+/* Generate data checksum for a single fs block, pointed to by @orig_iter. */
+void btrfs_csum_one_bio_block(struct btrfs_fs_info *fs_info, struct bio *bio,
+                             const struct bvec_iter *orig_iter, u8 *csum)
+{
+       struct btrfs_csum_ctx cctx;
+       struct bvec_iter iter = *orig_iter;
+       const u32 blocksize = fs_info->sectorsize;
+       u32 cur = 0;
+
+       btrfs_csum_init(&cctx, fs_info->csum_type);
+       while (cur < blocksize) {
+               struct page *page = bio_iter_page(bio, iter);
+               const u32 pg_off = bio_iter_offset(bio, iter);
+               const u32 cur_len = min(bio_iter_len(bio, iter), blocksize - cur);
+               void *kaddr;
+
+               kaddr = kmap_local_page(page) + pg_off;
+               btrfs_csum_update(&cctx, kaddr, cur_len);
+               kunmap_local(kaddr);
+
+               bio_advance_iter_single(bio, &iter, cur_len);
+               cur += cur_len;
+       }
+       btrfs_csum_final(&cctx, csum);
+}
+
 /*
  * Verify the checksum of a single data sector, which can be scattered at
  * different noncontiguous pages.
@@ -3551,7 +3577,6 @@ bool btrfs_bio_data_csum_ok(struct btrfs_bio *bbio,
        struct btrfs_inode *inode = bbio->inode;
        struct btrfs_fs_info *fs_info = inode->root->fs_info;
        struct bvec_iter iter = *orig_iter;
-       struct btrfs_csum_ctx cctx;
        const u32 blocksize = fs_info->sectorsize;
        const u32 bio_offset = (iter.bi_sector - bbio->saved_iter.bi_sector) << SECTOR_SHIFT;
        u64 file_offset = bbio->file_offset + bio_offset;
@@ -3576,22 +3601,7 @@ bool btrfs_bio_data_csum_ok(struct btrfs_bio *bbio,
 
        csum_expected = bbio->csum + (bio_offset >> fs_info->sectorsize_bits) *
                                fs_info->csum_size;
-       btrfs_csum_init(&cctx, fs_info->csum_type);
-       while (cur < blocksize) {
-               struct page *page = bio_iter_page(&bbio->bio, iter);
-               const u32 pg_off = bio_iter_offset(&bbio->bio, iter);
-               const u32 cur_len = min(bio_iter_len(&bbio->bio, iter), blocksize - cur);
-               void *kaddr;
-
-               kaddr = kmap_local_page(page) + pg_off;
-               btrfs_csum_update(&cctx, kaddr, cur_len);
-               kunmap_local(kaddr);
-
-               bio_advance_iter_single(&bbio->bio, &iter, cur_len);
-               cur += cur_len;
-       }
-       btrfs_csum_final(&cctx, csum);
-
+       btrfs_csum_one_bio_block(fs_info, &bbio->bio, orig_iter, csum);
        if (unlikely(memcmp(csum, csum_expected, fs_info->csum_size) != 0))
                goto zeroit;
        return true;
@@ -3601,8 +3611,6 @@ zeroit:
                                    bbio->mirror_num);
        if (dev)
                btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS);
-       cur = 0;
-       iter = *orig_iter;
        while (cur < blocksize) {
                struct page *page = bio_iter_page(&bbio->bio, iter);
                const u32 pg_off = bio_iter_offset(&bbio->bio, iter);