From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753652Ab1CEQtd (ORCPT ); Sat, 5 Mar 2011 11:49:33 -0500 Received: from smtp-03.mandic.com.br ([200.225.81.143]:36937 "EHLO smtp-03.mandic.com.br" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753523Ab1CEQtX (ORCPT ); Sat, 5 Mar 2011 11:49:23 -0500 From: Cesar Eduardo Barros To: linux-mm@kvack.org Cc: Andrew Morton , Hugh Dickins , KAMEZAWA Hiroyuki , Minchan Kim , Jens Axboe , linux-kernel@vger.kernel.org, Eric B Munson , Cesar Eduardo Barros Subject: [PATCHv2 24/24] sys_swapon: separate final enabling of the swapfile Date: Sat, 5 Mar 2011 13:42:25 -0300 Message-Id: <1299343345-3984-25-git-send-email-cesarb@cesarb.net> X-Mailer: git-send-email 1.7.4 In-Reply-To: <1299343345-3984-1-git-send-email-cesarb@cesarb.net> References: <1299343345-3984-1-git-send-email-cesarb@cesarb.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The block in sys_swapon which does the final adjustments to the swap_info_struct and to swap_list is the same as the block which re-inserts it again at sys_swapoff on failure of try_to_unuse(). Move this code to a separate function, and use it both in sys_swapon and sys_swapoff. Signed-off-by: Cesar Eduardo Barros Tested-by: Eric B Munson Acked-by: Eric B Munson --- mm/swapfile.c | 84 ++++++++++++++++++++++++++++---------------------------- 1 files changed, 42 insertions(+), 42 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index c9825aa..49eb310 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1550,6 +1550,36 @@ bad_bmap: goto out; } +static void enable_swap_info(struct swap_info_struct *p, int prio, + unsigned char *swap_map) +{ + int i, prev; + + spin_lock(&swap_lock); + if (prio >= 0) + p->prio = prio; + else + p->prio = --least_priority; + p->swap_map = swap_map; + p->flags |= SWP_WRITEOK; + nr_swap_pages += p->pages; + total_swap_pages += p->pages; + + /* insert swap space into swap_list: */ + prev = -1; + for (i = swap_list.head; i >= 0; i = swap_info[i]->next) { + if (p->prio >= swap_info[i]->prio) + break; + prev = i; + } + p->next = i; + if (prev < 0) + swap_list.head = swap_list.next = p->type; + else + swap_info[prev]->next = p->type; + spin_unlock(&swap_lock); +} + SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) { struct swap_info_struct *p = NULL; @@ -1621,26 +1651,14 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) current->flags &= ~PF_OOM_ORIGIN; if (err) { + /* + * reading p->prio and p->swap_map outside the lock is + * safe here because only sys_swapon and sys_swapoff + * change them, and there can be no other sys_swapon or + * sys_swapoff for this swap_info_struct at this point. + */ /* re-insert swap space back into swap_list */ - spin_lock(&swap_lock); - if (p->prio < 0) - p->prio = --least_priority; - p->flags |= SWP_WRITEOK; - nr_swap_pages += p->pages; - total_swap_pages += p->pages; - - prev = -1; - for (i = swap_list.head; i >= 0; i = swap_info[i]->next) { - if (p->prio >= swap_info[i]->prio) - break; - prev = i; - } - p->next = i; - if (prev < 0) - swap_list.head = swap_list.next = type; - else - swap_info[prev]->next = type; - spin_unlock(&swap_lock); + enable_swap_info(p, p->prio, p->swap_map); goto out_dput; } @@ -2037,7 +2055,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) char *name; struct file *swap_file = NULL; struct address_space *mapping; - int i, prev; + int i; + int prio; int error; union swap_header *swap_header; int nr_extents; @@ -2134,30 +2153,11 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) } mutex_lock(&swapon_mutex); - spin_lock(&swap_lock); + prio = -1; if (swap_flags & SWAP_FLAG_PREFER) - p->prio = + prio = (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; - else - p->prio = --least_priority; - p->swap_map = swap_map; - p->flags |= SWP_WRITEOK; - nr_swap_pages += p->pages; - total_swap_pages += p->pages; - - /* insert swap space into swap_list: */ - prev = -1; - for (i = swap_list.head; i >= 0; i = swap_info[i]->next) { - if (p->prio >= swap_info[i]->prio) - break; - prev = i; - } - p->next = i; - if (prev < 0) - swap_list.head = swap_list.next = p->type; - else - swap_info[prev]->next = p->type; - spin_unlock(&swap_lock); + enable_swap_info(p, prio, swap_map); printk(KERN_INFO "Adding %uk swap on %s. " "Priority:%d extents:%d across:%lluk %s%s\n", -- 1.7.4