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Subject: Re: [PATCH v3] bcache: avoid oversized read request in cache missing
 code path
To:     Christoph Hellwig <hch@infradead.org>
Cc:     linux-bcache@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Kent Overstreet <kent.overstreet@gmail.com>
References: <20210518110009.11413-1-colyli@suse.de>
 <YKYYNVD+NsXaOFNe@infradead.org>
From:   Coly Li <colyli@suse.de>
Message-ID: <fea14938-8347-d549-4a2a-4f1810e02bf7@suse.de>
Date:   Fri, 21 May 2021 11:30:08 +0800
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On 5/20/21 4:05 PM, Christoph Hellwig wrote:
> This fix is pretty gross.  Adding pages to bios can fail for all kinds
> of reasons, so the fix is to use bio_add_page and check its return
> value, and if it needs another bio keep looping and chaining more bios.
> 

OK, I will try this idea and avoid to access BIO_MAX_VECS directly.

> And maybe capping the readahead to some sane upper bound still makes
> sense, but it should never look at BIO_MAX_VECS for that.
> 

Thanks for the hint.

Coly Li