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Date: Mon, 26 Feb 2024 13:21:56 +0000
From: Matthew Wilcox <willy@infradead.org>
To: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, david@fromorbit.com,
	chandan.babu@oracle.com, akpm@linux-foundation.org,
	mcgrof@kernel.org, ziy@nvidia.com, hare@suse.de, djwong@kernel.org,
	gost.dev@samsung.com, linux-mm@kvack.org,
	Pankaj Raghav <p.raghav@samsung.com>
Subject: Re: [PATCH 12/13] xfs: make the calculation generic in
 xfs_sb_validate_fsb_count()
Message-ID: <ZdyQdGkSIw9OsSqc@casper.infradead.org>
References: <20240226094936.2677493-1-kernel@pankajraghav.com>
 <20240226094936.2677493-13-kernel@pankajraghav.com>
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On Mon, Feb 26, 2024 at 10:49:35AM +0100, Pankaj Raghav (Samsung) wrote:
> +	if (check_mul_overflow(nblocks, (1 << sbp->sb_blocklog), &bytes))

Why would you not use check_shl_overflow()?

> +		return -EFBIG;
> +
> +	mapping_count = bytes >> PAGE_SHIFT;
>  	/* Limited by ULONG_MAX of page cache index */
> -	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
> +	if (mapping_count > ULONG_MAX)
>  		return -EFBIG;
>  	return 0;
>  }
> -- 
> 2.43.0
>