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Date: Thu, 13 Jun 2024 10:45:45 +0200
From: Christoph Hellwig <hch@lst.de>
To: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
Cc: david@fromorbit.com, djwong@kernel.org, chandan.babu@oracle.com,
	brauner@kernel.org, akpm@linux-foundation.org, willy@infradead.org,
	mcgrof@kernel.org, linux-mm@kvack.org, hare@suse.de,
	linux-kernel@vger.kernel.org, yang@os.amperecomputing.com,
	Zi Yan <zi.yan@sent.com>, linux-xfs@vger.kernel.org,
	p.raghav@samsung.com, linux-fsdevel@vger.kernel.org, hch@lst.de,
	gost.dev@samsung.com, cl@os.amperecomputing.com,
	john.g.garry@oracle.com
Subject: Re: [PATCH v7 10/11] xfs: make the calculation generic in
 xfs_sb_validate_fsb_count()
Message-ID: <20240613084545.GB23371@lst.de>
References: <20240607145902.1137853-1-kernel@pankajraghav.com> <20240607145902.1137853-11-kernel@pankajraghav.com>
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> +	uint64_t		max_index;
> +	uint64_t		max_bytes;
> +
>  	ASSERT(PAGE_SHIFT >= sbp->sb_blocklog);
>  	ASSERT(sbp->sb_blocklog >= BBSHIFT);
>  
> +	if (check_shl_overflow(nblocks, sbp->sb_blocklog, &max_bytes))
> +		return -EFBIG;
> +
>  	/* Limited by ULONG_MAX of page cache index */
> -	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
> +	max_index = max_bytes >> PAGE_SHIFT;
> +
> +	if (max_index > ULONG_MAX)

Do we really need the max_index variable for a single user here?
Or do you plan to add more uses of it later (can't really think of one
though)?