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Wong" , Andrew Morton , Christian Brauner , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/6] fs: add CONFIG_BUFFER_HEAD Message-ID: References: <20230720140452.63817-1-hch@lst.de> <20230720140452.63817-7-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230720140452.63817-7-hch@lst.de> X-Stat-Signature: 71gnuqu4g5thabcm7zzn83y8k7qri5mk X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: C02894000B X-Rspam-User: X-HE-Tag: 1689864324-513786 X-HE-Meta: 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 LTIjVlqF gG0RO5LtVGFqF7GNMnzNsMXlKzALa2CVUdLiV8dLX/66cnlajMgruJp3m3cBoc0+BJPAXnJ5VIS4EABoXwY1EQDwLcU8QSWocsFuRPQMOs66Cnbiw2qRfhTyspctuXhaYbkL7rBOIdE1OG+3MOGrxaSHIS03HxLRJEmp8O4KXEzXKhfH5JOXJ0kXOHw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Jul 20, 2023 at 04:04:52PM +0200, Christoph Hellwig wrote: > @@ -400,7 +391,8 @@ static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > iomap->type = IOMAP_MAPPED; > iomap->addr = iomap->offset; > iomap->length = isize - iomap->offset; > - iomap->flags |= IOMAP_F_BUFFER_HEAD; > + if (IS_ENABLED(CONFIG_BUFFER_HEAD)) > + iomap->flags |= IOMAP_F_BUFFER_HEAD; Wouldn't it be simpler to do ... +#ifdef CONFIG_BUFFER_HEAD #define IOMAP_F_BUFFER_HEAD (1U << 4) +#else +#define IOMAP_F_BUFFER_HEAD 0 +#endif in include/linux/iomap.h ? > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 0607790827b48a..6dc585c010c020 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -41,6 +41,12 @@ static inline struct iomap_page *to_iomap_page(struct folio *folio) > return NULL; > } > > +static inline bool iomap_use_buffer_heads(const struct iomap *iomap) > +{ > + return IS_ENABLED(CONFIG_BUFFER_HEAD) && > + (iomap->flags & IOMAP_F_BUFFER_HEAD); > +} ... because this function then goes away. > @@ -675,7 +681,7 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, > > if (srcmap->type == IOMAP_INLINE) > status = iomap_write_begin_inline(iter, folio); > - else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) > + else if (iomap_use_buffer_heads(srcmap)) ... as this will be optimised away.