From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F8EA1A256E; Fri, 9 Jan 2026 18:14:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767982483; cv=none; b=AHTAdwF5j7thp7f2NpkWDjc1s7U5+TEudX+nvsSpVHQS8SRdkbWfmIYy8zWf8cAyy2LMXah8kxm1Yz3nUwYp9bwdOkKUK4cFWffNJq/9g5tTC9cYLgvZV4o5QjmTCF1pc0cDFCId4fqoTVLsOvjVDQjgVMNJicXjjDrsT8s6du4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767982483; c=relaxed/simple; bh=D3sAcAQ7a72l6rkZ0vUO4cd30Fr3P4FlXUAXDmvF250=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=SYmBHxY8ZH6XS+KtnYJ1AxTn0E6HuOopld1S9Aw/QaQxzJYmBEWdfc3ScGMMfcj1SWcQtCedgnJHYjINu4ACne2kEz9KnjMv10Rgm5ZJyKy4yMr+Qid0kGocTuQVgOL+pyirr+A5zqQNL5ZKsQNH2dZ9VkcI86p8CuIe7Go+rgE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UMumko4L; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UMumko4L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 28C48C4CEF1; Fri, 9 Jan 2026 18:14:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767982483; bh=D3sAcAQ7a72l6rkZ0vUO4cd30Fr3P4FlXUAXDmvF250=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UMumko4LbvmJitdMGI1Z305NZuO/VqFkUoxywLmzdQvYoQfqYRsT4dmoWb3mtUkmE MWLTKQx0A2r6o5xK07beirTFpxuZXyZnK18i7DvSp7ncmLl+U9UaWf2IensqNEEzmt aALnWUzCHmvoQfQZdCmmtPd3OIzsvFBYVkMW7g6HUefOCnBQWYknpRkOWWVXG2JwNT vNp4AQi2PD8nRM1xe0XK/Qe9LvTezvXicCt8KbTqPI0+sAe8sn2l3t4GZNlzUCjpfj xHwsqZ88RFZsNIGIezRadirwxZo6LfDIpqud6ZgAXAsARPOf5tQvtA0LmPVw62af2/ 7uo2WfqXOkDbQ== Date: Fri, 9 Jan 2026 10:14:42 -0800 From: "Darrick J. Wong" To: Hongbo Li Cc: hsiangkao@linux.alibaba.com, chao@kernel.org, brauner@kernel.org, amir73il@gmail.com, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v14 01/10] iomap: stash iomap read ctx in the private field of iomap_iter Message-ID: <20260109181442.GA15532@frogsfrogsfrogs> References: <20260109102856.598531-1-lihongbo22@huawei.com> <20260109102856.598531-2-lihongbo22@huawei.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260109102856.598531-2-lihongbo22@huawei.com> On Fri, Jan 09, 2026 at 10:28:47AM +0000, Hongbo Li wrote: > It's useful to get filesystem-specific information using the > existing private field in the @iomap_iter passed to iomap_{begin,end} > for advanced usage for iomap buffered reads, which is much like the > current iomap DIO. > > For example, EROFS needs it to: > > - implement an efficient page cache sharing feature, since iomap > needs to apply to anon inode page cache but we'd like to get the > backing inode/fs instead, so filesystem-specific private data is > needed to keep such information; > > - pass in both struct page * and void * for inline data to avoid > kmap_to_page() usage (which is bogus). > > Signed-off-by: Hongbo Li > Reviewed-by: Gao Xiang This looks like a dead simple patch to allow iomap pagecache users to set iomap_iter::private, so no objections here: Reviewed-by: "Darrick J. Wong" --D > --- > fs/fuse/file.c | 4 ++-- > fs/iomap/buffered-io.c | 6 ++++-- > include/linux/iomap.h | 8 ++++---- > 3 files changed, 10 insertions(+), 8 deletions(-) > > diff --git a/fs/fuse/file.c b/fs/fuse/file.c > index 01bc894e9c2b..f5d8887c1922 100644 > --- a/fs/fuse/file.c > +++ b/fs/fuse/file.c > @@ -979,7 +979,7 @@ static int fuse_read_folio(struct file *file, struct folio *folio) > return -EIO; > } > > - iomap_read_folio(&fuse_iomap_ops, &ctx); > + iomap_read_folio(&fuse_iomap_ops, &ctx, NULL); > fuse_invalidate_atime(inode); > return 0; > } > @@ -1081,7 +1081,7 @@ static void fuse_readahead(struct readahead_control *rac) > if (fuse_is_bad(inode)) > return; > > - iomap_readahead(&fuse_iomap_ops, &ctx); > + iomap_readahead(&fuse_iomap_ops, &ctx, NULL); > } > > static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to) > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index e5c1ca440d93..5f7dcbabbda3 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -555,13 +555,14 @@ static int iomap_read_folio_iter(struct iomap_iter *iter, > } > > void iomap_read_folio(const struct iomap_ops *ops, > - struct iomap_read_folio_ctx *ctx) > + struct iomap_read_folio_ctx *ctx, void *private) > { > struct folio *folio = ctx->cur_folio; > struct iomap_iter iter = { > .inode = folio->mapping->host, > .pos = folio_pos(folio), > .len = folio_size(folio), > + .private = private, > }; > size_t bytes_submitted = 0; > int ret; > @@ -620,13 +621,14 @@ static int iomap_readahead_iter(struct iomap_iter *iter, > * the filesystem to be reentered. > */ > void iomap_readahead(const struct iomap_ops *ops, > - struct iomap_read_folio_ctx *ctx) > + struct iomap_read_folio_ctx *ctx, void *private) > { > struct readahead_control *rac = ctx->rac; > struct iomap_iter iter = { > .inode = rac->mapping->host, > .pos = readahead_pos(rac), > .len = readahead_length(rac), > + .private = private, > }; > size_t cur_bytes_submitted; > > diff --git a/include/linux/iomap.h b/include/linux/iomap.h > index 520e967cb501..441d614e9fdf 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -341,9 +341,9 @@ ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, > const struct iomap_ops *ops, > const struct iomap_write_ops *write_ops, void *private); > void iomap_read_folio(const struct iomap_ops *ops, > - struct iomap_read_folio_ctx *ctx); > + struct iomap_read_folio_ctx *ctx, void *private); > void iomap_readahead(const struct iomap_ops *ops, > - struct iomap_read_folio_ctx *ctx); > + struct iomap_read_folio_ctx *ctx, void *private); > bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count); > struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len); > bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags); > @@ -595,7 +595,7 @@ static inline void iomap_bio_read_folio(struct folio *folio, > .cur_folio = folio, > }; > > - iomap_read_folio(ops, &ctx); > + iomap_read_folio(ops, &ctx, NULL); > } > > static inline void iomap_bio_readahead(struct readahead_control *rac, > @@ -606,7 +606,7 @@ static inline void iomap_bio_readahead(struct readahead_control *rac, > .rac = rac, > }; > > - iomap_readahead(ops, &ctx); > + iomap_readahead(ops, &ctx, NULL); > } > #endif /* CONFIG_BLOCK */ > > -- > 2.22.0 > >