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Date: Thu, 7 Nov 2024 08:20:53 +0100
From: Christoph Hellwig <hch@lst.de>
To: Kundan Kumar <kundan.kumar@samsung.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 2/2] block: share more code for bio addition helpers
Message-ID: <20241107072053.GA4112@lst.de>
References: <20241105155235.460088-1-hch@lst.de> <20241105155235.460088-3-hch@lst.de> <CGME20241106101119epcas5p474ef1db0344f36c701535643af318f2a@epcas5p4.samsung.com> <20241106100338.35xxy2mcpp4u36xl@green245>
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On Wed, Nov 06, 2024 at 03:33:38PM +0530, Kundan Kumar wrote:
>> -int bio_add_page(struct bio *bio, struct page *page,
>> -		 unsigned int len, unsigned int offset)
>> +static int bio_do_add_page(struct bio *bio, struct page *page,
>> +		 unsigned int len, unsigned int offset, bool *same_page)
>
> As we are passing length within a folio, values will reach near UINT_MAX.
> It will be better to make len and offset as size_t, also to add a check like :
> if (len > UINT_MAX || offset > UINT_MAX)
> 		return 0;

Not sure what the point is.  IFF we get folio sizes overflowing an
unsigned int we'll have a massive problem as it will overflow the
bv_offset and bv_len fields.  So we'd need to address that first before
doing anything else.

>> {
>> -	bool same_page = false;
>
> nit: extra line got added

Yes, the previous code was missing the empty line after the variable
declaration, so this got fixed.