Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 21 Jul 2021 04:42:36 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Mike Rapoport <rppt@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, Jeff Layton <jlayton@kernel.org>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        William Kucharski <william.kucharski@oracle.com>,
        Christoph Hellwig <hch@lst.de>,
        David Howells <dhowells@redhat.com>
Subject: Re: [PATCH v14 002/138] mm: Introduce struct folio
Message-ID: <YPeXrDf2RRJmXMFM@casper.infradead.org>
References: <20210715033704.692967-1-willy@infradead.org>
 <20210715033704.692967-3-willy@infradead.org>
 <YPaoBcXmrLv7zpD2@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YPaoBcXmrLv7zpD2@kernel.org>
Precedence: bulk

On Tue, Jul 20, 2021 at 01:40:05PM +0300, Mike Rapoport wrote:
> > +/**
> > + * folio_shift - The number of bits covered by this folio.
> 
> For me this sounds like the size of the folio in bits.
> Maybe just repeat "The base-2 logarithm of the size of this folio" here and
> in return description?
> 
> > + * @folio: The folio.
> > + *
> > + * A folio contains a number of bytes which is a power-of-two in size.
> > + * This function tells you which power-of-two the folio is.
> > + *
> > + * Context: The caller should have a reference on the folio to prevent
> > + * it from being split.  It is not necessary for the folio to be locked.
> > + * Return: The base-2 logarithm of the size of this folio.
> > + */

I've gone with:

 /**
- * folio_shift - The number of bits covered by this folio.
+ * folio_shift - The size of the memory described by this folio.
  * @folio: The folio.
  *
- * A folio contains a number of bytes which is a power-of-two in size.
- * This function tells you which power-of-two the folio is.
+ * A folio represents a number of bytes which is a power-of-two in size.
+ * This function tells you which power-of-two the folio is.  See also
+ * folio_size() and folio_order().
  *
  * Context: The caller should have a reference on the folio to prevent
  * it from being split.  It is not necessary for the folio to be locked.