Re: [PATCH RFC] btrfs: allow extent buffer helpers to skip cross-page handling

[David Sterba <dsterba@suse.cz>]

On Thu, Nov 23, 2023 at 06:31:41AM +1030, Qu Wenruo wrote:
> 
> 
> On 2023/11/23 00:16, David Sterba wrote:
> > On Thu, Nov 16, 2023 at 03:49:06PM +1030, Qu Wenruo wrote:
> >> --- a/fs/btrfs/disk-io.c
> >> +++ b/fs/btrfs/disk-io.c
> >> @@ -80,8 +80,16 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result)
> >>   	char *kaddr;
> >>   	int i;
> >>
> >> +	memset(result, 0, BTRFS_CSUM_SIZE);
> >>   	shash->tfm = fs_info->csum_shash;
> >>   	crypto_shash_init(shash);
> >> +
> >> +	if (buf->addr) {
> >> +		crypto_shash_digest(shash, buf->addr + offset_in_page(buf->start) + BTRFS_CSUM_SIZE,
> >> +				    buf->len - BTRFS_CSUM_SIZE, result);
> >> +		return;
> >> +	}
> >
> > This duplicates the address and size
> >> +
> >>   	kaddr = page_address(buf->pages[0]) + offset_in_page(buf->start);
> >>   	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
> >>   			    first_page_part - BTRFS_CSUM_SIZE);
> >> @@ -90,7 +98,6 @@ static void csum_tree_block(struct extent_buffer *buf, u8 *result)
> >>   		kaddr = page_address(buf->pages[i]);
> >>   		crypto_shash_update(shash, kaddr, PAGE_SIZE);
> >>   	}
> >> -	memset(result, 0, BTRFS_CSUM_SIZE);
> >>   	crypto_shash_final(shash, result);
> >
> > I'd like to have only one code doing the crypto_shash_ calls, so I'm
> > suggesting this as the final code (the diff is not clear);
> 
> This looks good to me, mind to update it inside your branch?

There's something wrong with my updates, it fails in the first test so
I've verified your works and the used it in misc-next for now.