linux-kernel - Re: [PATCH 1/3] erofs: get rid of erofs_{find,insert}

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <cd756ca4-e83b-4b10-8792-fc0f1c1ae2fa@vivo.com>
Date: Fri, 18 Oct 2024 04:30:35 +0000
From: Chunhai Guo <guochunhai@...o.com>
To: Gao Xiang <hsiangkao@...ux.alibaba.com>, "linux-erofs@...ts.ozlabs.org"
	<linux-erofs@...ts.ozlabs.org>
CC: LKML <linux-kernel@...r.kernel.org>, Chunhai Guo <guochunhai@...o.com>
Subject: Re: [PATCH 1/3] erofs: get rid of erofs_{find,insert}_workgroup

> @@ -789,7 +798,16 @@ static int z_erofs_pcluster_begin(struct z_erofs_decompress_frontend *fe)
>   	DBG_BUGON(fe->owned_head == Z_EROFS_PCLUSTER_NIL);
>   
>   	if (!(map->m_flags & EROFS_MAP_META)) {
> -		grp = erofs_find_workgroup(sb, blknr);
> +		while (1) {
> +			rcu_read_lock();
> +			grp = xa_load(&EROFS_SB(sb)->managed_pslots, blknr);
> +			if (erofs_workgroup_get(grp)) {
I guess here should be modified as below, please refer to 
erofs_find_workgroup().

			if (grp && erofs_workgroup_get(grp)) {

> +				DBG_BUGON(blknr != grp->index);
> +				rcu_read_unlock();
> +				break;
> +			}
> +			rcu_read_unlock();
> +		}
>   	} else if ((map->m_pa & ~PAGE_MASK) + map->m_plen > PAGE_SIZE) {
>   		DBG_BUGON(1);
>   		return -EFSCORRUPTED;
> diff --git a/fs/erofs/zutil.c b/fs/erofs/zutil.c
> index 37afe2024840..218b0249a482 100644
> --- a/fs/erofs/zutil.c
> +++ b/fs/erofs/zutil.c
> @@ -214,7 +214,7 @@ void erofs_release_pages(struct page **pagepool)
>   	}
>   }
>   
> -static bool erofs_workgroup_get(struct erofs_workgroup *grp)
> +bool erofs_workgroup_get(struct erofs_workgroup *grp)
>   {
>   	if (lockref_get_not_zero(&grp->lockref))
>   		return true;
> @@ -231,54 +231,6 @@ static bool erofs_workgroup_get(struct erofs_workgroup *grp)
>   	return true;
>   }
>   
> -struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
> -					     pgoff_t index)
> -{
> -	struct erofs_sb_info *sbi = EROFS_SB(sb);
> -	struct erofs_workgroup *grp;
> -
> -repeat:
> -	rcu_read_lock();
> -	grp = xa_load(&sbi->managed_pslots, index);
> -	if (grp) {
Please refer to this logic.
> -		if (!erofs_workgroup_get(grp)) {
> -			/* prefer to relax rcu read side */
> -			rcu_read_unlock();
> -			goto repeat;
> -		}
> -
> -		DBG_BUGON(index != grp->index);
> -	}
> -	rcu_read_unlock();
> -	return grp;
> -}

Thanks,

Chunhai