* [PATCH] btrfs: switch to on-stack csum buffer in csum_tree_block
@ 2017-11-06 18:23 David Sterba
0 siblings, 0 replies; only message in thread
From: David Sterba @ 2017-11-06 18:23 UTC (permalink / raw)
To: linux-btrfs; +Cc: David Sterba
The maximum size of a checksum buffer is known, BTRFS_CSUM_SIZE, and we
don't have to allocate it dynamically. This code path is not used at all
as we have only the crc32c and use an on-stack buffer already.
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/disk-io.c | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5713c50959e0..53c9145a56e9 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -285,7 +285,7 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
int verify)
{
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
- char *result = NULL;
+ char result[BTRFS_CSUM_SIZE];
unsigned long len;
unsigned long cur_len;
unsigned long offset = BTRFS_CSUM_SIZE;
@@ -294,7 +294,6 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
unsigned long map_len;
int err;
u32 crc = ~(u32)0;
- unsigned long inline_result;
len = buf->len - offset;
while (len > 0) {
@@ -308,13 +307,7 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
len -= cur_len;
offset += cur_len;
}
- if (csum_size > sizeof(inline_result)) {
- result = kzalloc(csum_size, GFP_NOFS);
- if (!result)
- return -ENOMEM;
- } else {
- result = (char *)&inline_result;
- }
+ memset(result, 0, BTRFS_CSUM_SIZE);
btrfs_csum_final(crc, result);
@@ -329,15 +322,12 @@ static int csum_tree_block(struct btrfs_fs_info *fs_info,
"%s checksum verify failed on %llu wanted %X found %X level %d",
fs_info->sb->s_id, buf->start,
val, found, btrfs_header_level(buf));
- if (result != (char *)&inline_result)
- kfree(result);
return -EUCLEAN;
}
} else {
write_extent_buffer(buf, result, 0, csum_size);
}
- if (result != (char *)&inline_result)
- kfree(result);
+
return 0;
}
--
2.14.3
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