From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 C599D3A5E78; Thu, 23 Jul 2026 05:47:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784785632; cv=none; b=OK/z78sD9u9pda0w9L5DgZbkv2w1iVRspFHP/r/A/ND2GvAlmMQqGqal/a/68lMsW04iO/VwJsjTvYoVDTCNRYWLTSKsv39QKuX4y6xawWNmsop8mFRP5BuXo2f0gWAIae1VI0gn6ZatrqUeKtM1ngbjfJD1NHzYiesqJdemmI4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784785632; c=relaxed/simple; bh=JKlVujbKqPmSjU4imQ8+jc4U5jq+Qtfs4fW/S0ydewQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dejWfarDUZtBEokq9wv2J8plXURWiOg7zw9n6En43O5CcAlxvzTawYitVnvxxYpt4QEt/G+wLZuWy48cUpyb+uQwdwj1/5y6aELlooYtiRbfoO6ahwGi/Px/tRbf8umzQb3+QmJ7UvtXetgFs6sp/cFREUehwVaEEy1N5qhbX+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Q3GzORIT; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Q3GzORIT" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=SCgrBV4+wiYD8yTajffrCoLTiOuVuwvpUdCa94y7WYw=; b=Q3GzORIT8IOzxH4aY6CLKstcSn 8RWluq5HE3u2ureWMAc32d7zum9Dtn7XTrXkqpMQevAphF/RU/rizQhCD2WFKZGD2fXaB1puAfoV9 jfYGjSUVWuEwhRg3LjFY+3KWt7x0/U6FvyN762Kn27KdPm2T3+tVQ6tZD8PXElk8P0YS4xA1E7I0K Bq98lSMl2faOXexrO9n3XC50Lx7f/DbhodkZcRMvyv5APhB5KKZb6hw+Xd0XDYEiY6AC6Z5mdMveF 99AeknObJ78qDzaAPHRjRPniQ5tylPCiAiPrB0XT6/czQgybnJPfTHu1Y4G78WRnb4gGR6UODZFSp 111OQjeQ==; Received: from 217-76-162-32.static.highway.a1.net ([217.76.162.32] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmmGs-0000000DV1n-1gJf; Thu, 23 Jul 2026 05:47:04 +0000 From: Christoph Hellwig To: Cc: baoquan.he@linux.dev, akpm@linux-foundation.org, chrisl@kernel.org, usama.arif@linux.dev, kasong@tencent.com, nphamcs@gmail.com, shikemeng@huaweicloud.com, youngjun.park@lge.com, ryncsn@gmail.com, trondmy@kernel.org, anna@kernel.org, sfrench@samba.org, linux-mm@kvack.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org Subject: [PATCH 2/3] mm/swap: add a new swap_ops.h header to allow for pluggable swap ops Date: Thu, 23 Jul 2026 07:46:05 +0200 Message-ID: <20260723054622.3460249-3-hch@lst.de> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260723054622.3460249-1-hch@lst.de> References: <20260723054622.3460249-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Add a new header to declare the swap_iocb, swap_ops and swap_ctx to allow for swap_ops implementations outside of mm/page_io.c. This will be used to remove the double indirection for file system-based swap. There is no functional change, just a move of the declarations. Note that there already is a swapops.h header, which is totally unrelated to struct swap_ops. The close naming is a bit unfortunate, but I could not think of a better name for this header. Signed-off-by: Christoph Hellwig --- MAINTAINERS | 1 + include/linux/swap_ops.h | 39 +++++++++++++++++++++++++++++++++++++++ mm/madvise.c | 1 + mm/page_io.c | 10 +--------- mm/shmem.c | 1 + mm/swap.h | 23 +---------------------- mm/swap_state.c | 1 + mm/vmscan.c | 1 + mm/zswap.c | 2 +- 9 files changed, 47 insertions(+), 32 deletions(-) create mode 100644 include/linux/swap_ops.h diff --git a/MAINTAINERS b/MAINTAINERS index 15dd00c7ffec..713275f62ec4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17240,6 +17240,7 @@ S: Maintained F: Documentation/ABI/testing/sysfs-kernel-mm-swap F: Documentation/mm/swap-table.rst F: include/linux/swap.h +F: include/linux/swap_ops.h F: include/linux/swapfile.h F: include/linux/swapops.h F: mm/page_io.c diff --git a/include/linux/swap_ops.h b/include/linux/swap_ops.h new file mode 100644 index 000000000000..e92b4f532604 --- /dev/null +++ b/include/linux/swap_ops.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _MM_SWAP_OPS_H +#define _MM_SWAP_OPS_H + +#include /* for SWAP_CLUSTER_MAX */ + +struct swap_iocb { + union { + struct kiocb iocb; + struct bio bio; + }; + struct bio_vec bvecs[SWAP_CLUSTER_MAX]; + int nr_bvecs; + int len; +}; + +struct swap_io_ctx { + struct swap_iocb *sio; + struct swap_info_struct *sis; +}; + +/* + * SWAP_OPS_F_REQUIRE_NOFS: + * When set, all reclaim operations must operated as GFS_NOFS and not + * just GFP_NOIO, as GFP_NOIO allocations could recourse into the + * file system backing this swap file. + */ +#define SWAP_OPS_F_REQUIRE_NOFS (1U << 0) + +struct swap_ops { + unsigned int flags; + + bool (*can_merge)(struct folio *folio, struct folio *prev_folio, + size_t prev_folio_size, int rw); + void (*submit_write)(struct swap_io_ctx *ctx); + void (*submit_read)(struct swap_io_ctx *ctx); +}; + +#endif /* _MM_SWAP_OPS_H */ diff --git a/mm/madvise.c b/mm/madvise.c index 07a21ca31bad..c179938097bf 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -32,6 +32,7 @@ #include #include #include +#include #include diff --git a/mm/page_io.c b/mm/page_io.c index c984a4023a65..e741e67d6592 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -25,6 +25,7 @@ #include #include #include +#include #include "swap.h" #include "swap_table.h" @@ -300,15 +301,6 @@ static bool folio_blkg_can_merge(struct folio *folio, struct folio *prev_folio) #define bio_associate_blkg_from_page(bio, folio) do { } while (0) #endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */ -struct swap_iocb { - union { - struct kiocb iocb; - struct bio bio; - }; - struct bio_vec bvecs[SWAP_CLUSTER_MAX]; - int nr_bvecs; - int len; -}; static mempool_t *sio_pool; int sio_pool_init(void) diff --git a/mm/shmem.c b/mm/shmem.c index 5071177059a9..797c42f024a0 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -41,6 +41,7 @@ #include #include #include +#include #include "swap.h" static struct vfsmount *shm_mnt __ro_after_init; diff --git a/mm/swap.h b/mm/swap.h index abd26588abd2..19ea61c97df2 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -8,6 +8,7 @@ struct mempolicy; struct swap_iocb; struct swap_memcg_table; +struct swap_io_ctx; #if defined(MAX_POSSIBLE_PHYSMEM_BITS) #define SWAP_CACHE_PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT) @@ -77,28 +78,6 @@ enum swap_cluster_flags { CLUSTER_FLAG_MAX, }; -struct swap_io_ctx { - struct swap_iocb *sio; - struct swap_info_struct *sis; -}; - -/* - * SWAP_OPS_F_REQUIRE_NOFS: - * When set, all reclaim operations must operated as GFS_NOFS and not - * just GFP_NOIO, as GFP_NOIO allocations could recourse into the - * file system backing this swap file. - */ -#define SWAP_OPS_F_REQUIRE_NOFS (1U << 0) - -struct swap_ops { - unsigned int flags; - - bool (*can_merge)(struct folio *folio, struct folio *prev_folio, - size_t prev_folio_size, int rw); - void (*submit_write)(struct swap_io_ctx *ctx); - void (*submit_read)(struct swap_io_ctx *ctx); -}; - #ifdef CONFIG_SWAP #include /* for swp_offset */ #include /* for bio_end_io_t */ diff --git a/mm/swap_state.c b/mm/swap_state.c index 5be825911e64..b76eb3d876fd 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "internal.h" #include "swap_table.h" #include "swap.h" diff --git a/mm/vmscan.c b/mm/vmscan.c index 9b8ee902f972..efe24bb36ce1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -58,6 +58,7 @@ #include #include #include +#include #include #include diff --git a/mm/zswap.c b/mm/zswap.c index 4e76a4a87cdc..9c4c337790fd 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -20,7 +20,7 @@ #include #include #include -#include +#include #include #include #include -- 2.53.0