From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 899EDC43458 for ; Mon, 13 Jul 2026 09:34:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 812936B009E; Mon, 13 Jul 2026 05:34:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7C33B6B009F; Mon, 13 Jul 2026 05:34:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6B1476B00A0; Mon, 13 Jul 2026 05:34:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 3DF496B009E for ; Mon, 13 Jul 2026 05:34:40 -0400 (EDT) Received: from smtpin30.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BAFE140A8A for ; Mon, 13 Jul 2026 09:34:39 +0000 (UTC) X-FDA: 84983243478.30.3AFBBFC Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf03.hostedemail.com (Postfix) with ESMTP id 2FC712000A for ; Mon, 13 Jul 2026 09:34:38 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=CH4JxXDE; spf=none (imf03.hostedemail.com: domain of BATV+55c33cd1421391a2a6eb+8359+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+55c33cd1421391a2a6eb+8359+infradead.org+hch@bombadil.srs.infradead.org; dmarc=fail reason="No valid SPF, DKIM not aligned (relaxed)" header.from=lst.de (policy=none) ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1783935278; b=S4j8qj3k4G4mBTzvSCEN2MJ+vo5t2djGwDjYkyqI80MiEYbiV81FBAe/nfPTj3GJkG7bGP kFaYbjmgG4WPOnKemDshhQA+s/v2G2MNFqgi8uO+GeRoPgaEbDtHvKDfX0lM8Y0M/sCYF7 OUQITaOw6i/py1jdnhxWw8NNvDZWtR4= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=CH4JxXDE; spf=none (imf03.hostedemail.com: domain of BATV+55c33cd1421391a2a6eb+8359+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+55c33cd1421391a2a6eb+8359+infradead.org+hch@bombadil.srs.infradead.org; dmarc=fail reason="No valid SPF, DKIM not aligned (relaxed)" header.from=lst.de (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1783935278; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=88u9WXhIp3bQx/HiJ3WvBlExgjDVfNL/4o7C34bvgwY=; b=r/0R4UpC5zmbKbwAF/5boyNSRegMEE1EEh2cK/bKk4puFRTdJNiJld2v7XwCcj1CnU0YBo 32DCtGUH9+TfMJX9imLSDo3vLcchwJDVNantFmTFNmkVm4RiPFSnQBR/v5AOfGHCf2hjRB FbmV5X0fG028LLCd8DYFTq2UetosRtk= 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=88u9WXhIp3bQx/HiJ3WvBlExgjDVfNL/4o7C34bvgwY=; b=CH4JxXDE2/p5RiJg08xxrcu3Td USkBrZ7Un7UovQ1HuzTQkeSDx1XFz9lwbuJHFhzd+H6nZMOnTozwf5hAUZE6zf6vtY23I3QxPGpGL T6LSuvLKyC31d7xgtrcVbBRGkptx+IfbtJoTldHwlmJZEXldM5vXr9FsIs5cGd6u7iPf9FPdssVL2 LaWEj6IOyp3l1NlXHW4FvpQTvvp34b8TLFAcpiCcTz1N2hpavaMikGDMV9qwhKbJcBbvrDeiaxA54 F1RZzzItt6TB9nT32C8jp+tXaHyyCwr1ZeqQFgq5kOoKkJTVgyoNs9vhsPeFa22Xdi4FAnrkDNzB6 7T0kQqIg==; Received: from [2001:4bb8:2c2:7dc3:4a7a:b4de:3d88:bc44] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wjD3X-00000008kli-1D10; Mon, 13 Jul 2026 09:34:31 +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, linux-mm@kvack.org Subject: [PATCH 5/7] mm/swap: use swap_ops to register swap device's methods Date: Mon, 13 Jul 2026 11:33:42 +0200 Message-ID: <20260713093350.2154226-6-hch@lst.de> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260713093350.2154226-1-hch@lst.de> References: <20260713093350.2154226-1-hch@lst.de> 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 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 2FC712000A X-Stat-Signature: 1rojdtnzhamngfogxsc8ygokf5ujm9fb X-HE-Tag: 1783935278-848282 X-HE-Meta: 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 jRF/6RBu 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This simplifies codes and makes logic clearer. And also makes later any new swap device type being added easier to handle. Currently there are two types of swap devices: fs and bdev. Suggested-by: Chris Li Signed-off-by: Baoquan He [hch: updated for the new submit and can_merge abstraction] Signed-off-by: Christoph Hellwig Reviewed-by: Nhat Pham --- include/linux/swap.h | 1 + mm/page_io.c | 68 ++++++++++++++++++++++++++++---------------- mm/swap.h | 10 +++++++ mm/swapfile.c | 4 +++ 4 files changed, 58 insertions(+), 25 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 696ed01709c2..ee84d4cc8457 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -276,6 +276,7 @@ struct swap_info_struct { struct work_struct reclaim_work; /* reclaim worker */ struct list_head discard_clusters; /* discard clusters list */ struct plist_node avail_list; /* entry in swap_avail_head */ + const struct swap_ops *ops; }; static inline swp_entry_t page_swap_entry(struct page *page) diff --git a/mm/page_io.c b/mm/page_io.c index 56f21e49572e..c36b44ffe947 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -334,21 +334,7 @@ static bool swap_can_merge(struct swap_io_ctx *ctx, struct folio *folio, if (ctx->sis != sis) return false; - - if (sis->flags & SWP_FS_OPS) { - if (swap_dev_pos(folio->swap) != - swap_dev_pos(prev_folio->swap) + prev_folio_size) - return false; - } else { - if (swap_folio_sector(folio) != - swap_folio_sector(prev_folio) + - (prev_folio_size >> SECTOR_SHIFT)) - return false; - if (rw == WRITE && !folio_blkg_can_merge(folio, prev_folio)) - return false; - } - - return true; + return sis->ops->can_merge(folio, prev_folio, prev_folio_size, rw); } static void swap_add_folio(struct swap_io_ctx *ctx, struct folio *folio, int rw) @@ -646,6 +632,23 @@ static void swap_bdev_submit_read(struct swap_io_ctx *ctx) } } +static bool swap_bdev_can_merge(struct folio *folio, struct folio *prev_folio, + size_t prev_folio_size, int rw) +{ + if (swap_folio_sector(folio) != + swap_folio_sector(prev_folio) + (prev_folio_size >> SECTOR_SHIFT)) + return false; + if (rw == WRITE && !folio_blkg_can_merge(folio, prev_folio)) + return false; + return true; +} + +const struct swap_ops swap_bdev_ops = { + .submit_write = swap_bdev_submit_write, + .submit_read = swap_bdev_submit_read, + .can_merge = swap_bdev_can_merge, +}; + static void swap_fs_submit(struct swap_io_ctx *ctx, int rw) { struct swap_iocb *sio = ctx->sio; @@ -666,15 +669,34 @@ static void swap_fs_submit(struct swap_io_ctx *ctx, int rw) sio->iocb.ki_complete(&sio->iocb, ret); } +static void swap_fs_submit_write(struct swap_io_ctx *ctx) +{ + swap_fs_submit(ctx, WRITE); +} + +static void swap_fs_submit_read(struct swap_io_ctx *ctx) +{ + swap_fs_submit(ctx, READ); +} + +static bool swap_fs_can_merge(struct folio *folio, struct folio *prev_folio, + size_t prev_folio_size, int rw) +{ + return swap_dev_pos(folio->swap) == + swap_dev_pos(prev_folio->swap) + prev_folio_size; +} + +const struct swap_ops swap_fs_ops = { + .submit_write = swap_fs_submit_write, + .submit_read = swap_fs_submit_read, + .can_merge = swap_fs_can_merge, +}; + void swap_write_submit(struct swap_io_ctx *ctx) { if (!ctx->sio) return; - - if (ctx->sis->flags & SWP_FS_OPS) - swap_fs_submit(ctx, WRITE); - else - swap_bdev_submit_write(ctx); + ctx->sis->ops->submit_write(ctx); ctx->sio = NULL; ctx->sis = NULL; } @@ -683,11 +705,7 @@ void swap_read_submit(struct swap_io_ctx *ctx) { if (!ctx->sio) return; - - if (ctx->sis->flags & SWP_FS_OPS) - swap_fs_submit(ctx, READ); - else - swap_bdev_submit_read(ctx); + ctx->sis->ops->submit_read(ctx); ctx->sio = NULL; ctx->sis = NULL; } diff --git a/mm/swap.h b/mm/swap.h index 1d169bf96d1d..33a258c77064 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -82,6 +82,13 @@ struct swap_io_ctx { struct swap_info_struct *sis; }; +struct swap_ops { + 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 */ @@ -469,6 +476,9 @@ static inline unsigned int folio_swap_flags(struct folio *folio) #endif /* CONFIG_SWAP */ +extern const struct swap_ops swap_bdev_ops; +extern const struct swap_ops swap_fs_ops; + int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, struct list_head *folio_list); diff --git a/mm/swapfile.c b/mm/swapfile.c index 881511fb7a46..c6b3e4278045 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2950,6 +2950,8 @@ static int setup_swap_extents(struct swap_info_struct *sis, if (ret) return ret; + sis->ops = &swap_bdev_ops; + if (S_ISBLK(inode->i_mode)) { ret = add_swap_extent(sis, 0, sis->max, 0); *span = sis->pages; @@ -2960,6 +2962,8 @@ static int setup_swap_extents(struct swap_info_struct *sis, ret = mapping->a_ops->swap_activate(sis, swap_file, span); if (ret < 0) return ret; + if (sis->flags & SWP_FS_OPS) + sis->ops = &swap_fs_ops; sis->flags |= SWP_ACTIVATED; return ret; } -- 2.53.0