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From: Christoph Hellwig <hch@lst.de>
To: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Hongbo Li <lihongbo22@huawei.com>,
	chao@kernel.org, brauner@kernel.org, hch@lst.de,
	djwong@kernel.org, amir73il@gmail.com,
	linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v16 04/10] erofs: add erofs_inode_set_aops helper to set the aops.
Date: Fri, 23 Jan 2026 07:18:25 +0100	[thread overview]
Message-ID: <20260123061825.GA25722@lst.de> (raw)
In-Reply-To: <b20b263d-132b-464e-8314-d3f795e5e582@linux.alibaba.com>

On Thu, Jan 22, 2026 at 09:54:15PM +0800, Gao Xiang wrote:
>> @@ -455,6 +455,29 @@ static inline void *erofs_vm_map_ram(struct page **pages, unsigned int count)
>>   	return NULL;
>>   }
>>   +static inline int erofs_inode_set_aops(struct inode *inode,
>> +				       struct inode *realinode, bool no_fscache)
>> +{
>> +	if (erofs_inode_is_data_compressed(EROFS_I(realinode)->datalayout)) {
>> +		if (!IS_ENABLED(CONFIG_EROFS_FS_ZIP))
>> +			return -EOPNOTSUPP;
>> +		DO_ONCE_LITE_IF(realinode->i_blkbits != PAGE_SHIFT,
>> +			  erofs_info, realinode->i_sb,
>> +			  "EXPERIMENTAL EROFS subpage compressed block support in use. Use at your own risk!");
>> +		inode->i_mapping->a_ops = &z_erofs_aops;
>
> Is that available if CONFIG_EROFS_FS_ZIP is undefined?

z_erofs_aops is declared unconditionally, and the IS_ENABLED above
ensures the compiler will never generate a reference to it.

So this is fine, and a very usualy trick to make the code more
readable.


  reply	other threads:[~2026-01-23  6:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-22 13:37 [PATCH v16 00/10] erofs: Introduce page cache sharing feature Hongbo Li
2026-01-22 13:37 ` [PATCH v16 01/10] fs: Export alloc_empty_backing_file Hongbo Li
2026-01-22 13:37 ` [PATCH v16 02/10] erofs: decouple `struct erofs_anon_fs_type` Hongbo Li
2026-01-22 13:37 ` [PATCH v16 03/10] erofs: support user-defined fingerprint name Hongbo Li
2026-01-22 13:37 ` [PATCH v16 04/10] erofs: add erofs_inode_set_aops helper to set the aops Hongbo Li
2026-01-22 13:54   ` Gao Xiang
2026-01-23  6:18     ` Christoph Hellwig [this message]
2026-01-23  7:42       ` Gao Xiang
2026-01-23  8:21         ` Hongbo Li
2026-01-22 13:37 ` [PATCH v16 05/10] erofs: using domain_id in the safer way Hongbo Li
2026-01-22 13:37 ` [PATCH v16 06/10] erofs: introduce the page cache share feature Hongbo Li
2026-01-22 14:01   ` Gao Xiang
2026-01-22 15:09     ` Hongbo Li
2026-01-22 13:37 ` [PATCH v16 07/10] erofs: pass inode to trace_erofs_read_folio Hongbo Li
2026-01-22 13:37 ` [PATCH v16 08/10] erofs: support unencoded inodes for page cache share Hongbo Li
2026-01-22 13:37 ` [PATCH v16 09/10] erofs: support compressed " Hongbo Li
2026-01-22 13:37 ` [PATCH v16 10/10] erofs: implement .fadvise " Hongbo Li

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