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Date: Thu, 11 Sep 2025 08:10:33 +0200
From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 1/2] block: add a bio_init_inline helper
Message-ID: <20250911061033.GB12964@lst.de>
References: <20250908105653.4079264-1-hch@lst.de> <20250908105653.4079264-2-hch@lst.de> <b4b28858-0d55-4d98-99c8-d872e902515e@oracle.com>
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On Tue, Sep 09, 2025 at 09:43:55AM +0100, John Garry wrote:
>> +static inline void bio_init_inline(struct bio *bio, struct block_device *bdev,
>> +	      unsigned short max_vecs, blk_opf_t opf)
>> +{
>
> I suppose that a WARN_ON(max_vecs > BIO_MAX_INLINE_VECS) could be added, 
> but I don't think that we generally protect against such self-inflicted 
> programming errors.

It's not needed because there isn't actually any such limit.
BIO_MAX_INLINE_VECS is misnamed and misguided.  Various places in the
block layer require non-passthrough bios to not have more vectors than
BIO_MAX_VECS, while BIO_MAX_INLINE_VECS is a random upper bound for
passthrough I/O without a deeper meaning.