From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 715156B66A9 for ; Mon, 3 Sep 2018 03:22:35 -0400 (EDT) Received: by mail-pf1-f200.google.com with SMTP id q21-v6so10804204pff.21 for ; Mon, 03 Sep 2018 00:22:35 -0700 (PDT) Received: from mga07.intel.com (mga07.intel.com. [134.134.136.100]) by mx.google.com with ESMTPS id r24-v6si4679764pgg.403.2018.09.03.00.22.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Sep 2018 00:22:34 -0700 (PDT) From: Huang Ying Subject: [PATCH -V5 02/21] swap: Add __swap_duplicate_locked() Date: Mon, 3 Sep 2018 15:21:55 +0800 Message-Id: <20180903072214.24602-3-ying.huang@intel.com> In-Reply-To: <20180903072214.24602-1-ying.huang@intel.com> References: <20180903072214.24602-1-ying.huang@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , "Kirill A. Shutemov" , Andrea Arcangeli , Michal Hocko , Johannes Weiner , Shaohua Li , Hugh Dickins , Minchan Kim , Rik van Riel , Dave Hansen , Naoya Horiguchi , Zi Yan , Daniel Jordan The part of __swap_duplicate() with lock held is separated into a new function __swap_duplicate_locked(). Because we will add more logic about the PMD swap mapping into __swap_duplicate() and keep the most PTE swap mapping related logic in __swap_duplicate_locked(). Just mechanical code refactoring, there is no any functional change in this patch. Signed-off-by: "Huang, Ying" Cc: "Kirill A. Shutemov" Cc: Andrea Arcangeli Cc: Michal Hocko Cc: Johannes Weiner Cc: Shaohua Li Cc: Hugh Dickins Cc: Minchan Kim Cc: Rik van Riel Cc: Dave Hansen Cc: Naoya Horiguchi Cc: Zi Yan Cc: Daniel Jordan --- mm/swapfile.c | 63 +++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 35 insertions(+), 28 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 1996dcd732b6..532de6f8ff39 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3436,32 +3436,12 @@ void si_swapinfo(struct sysinfo *val) spin_unlock(&swap_lock); } -/* - * Verify that a swap entry is valid and increment its swap map count. - * - * Returns error code in following case. - * - success -> 0 - * - swp_entry is invalid -> EINVAL - * - swp_entry is migration entry -> EINVAL - * - swap-cache reference is requested but there is already one. -> EEXIST - * - swap-cache reference is requested but the entry is not used. -> ENOENT - * - swap-mapped reference requested but needs continued swap count. -> ENOMEM - */ -static int __swap_duplicate(swp_entry_t entry, unsigned char usage) +static int __swap_duplicate_locked(struct swap_info_struct *p, + unsigned long offset, unsigned char usage) { - struct swap_info_struct *p; - struct swap_cluster_info *ci; - unsigned long offset; unsigned char count; unsigned char has_cache; - int err = -EINVAL; - - p = get_swap_device(entry); - if (!p) - goto out; - - offset = swp_offset(entry); - ci = lock_cluster_or_swap_info(p, offset); + int err = 0; count = p->swap_map[offset]; @@ -3471,12 +3451,11 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) */ if (unlikely(swap_count(count) == SWAP_MAP_BAD)) { err = -ENOENT; - goto unlock_out; + goto out; } has_cache = count & SWAP_HAS_CACHE; count &= ~SWAP_HAS_CACHE; - err = 0; if (usage == SWAP_HAS_CACHE) { @@ -3503,11 +3482,39 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) p->swap_map[offset] = count | has_cache; -unlock_out: +out: + return err; +} + +/* + * Verify that a swap entry is valid and increment its swap map count. + * + * Returns error code in following case. + * - success -> 0 + * - swp_entry is invalid -> EINVAL + * - swp_entry is migration entry -> EINVAL + * - swap-cache reference is requested but there is already one. -> EEXIST + * - swap-cache reference is requested but the entry is not used. -> ENOENT + * - swap-mapped reference requested but needs continued swap count. -> ENOMEM + */ +static int __swap_duplicate(swp_entry_t entry, unsigned char usage) +{ + struct swap_info_struct *p; + struct swap_cluster_info *ci; + unsigned long offset; + int err = -EINVAL; + + p = get_swap_device(entry); + if (!p) + goto out; + + offset = swp_offset(entry); + ci = lock_cluster_or_swap_info(p, offset); + err = __swap_duplicate_locked(p, offset, usage); unlock_cluster_or_swap_info(p, ci); + + put_swap_device(p); out: - if (p) - put_swap_device(p); return err; } -- 2.16.4