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 X-Spam-Level: X-Spam-Status: No, score=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB72AC4708F for ; Sat, 29 May 2021 00:42:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A015F6113D for ; Sat, 29 May 2021 00:42:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229744AbhE2AoR (ORCPT ); Fri, 28 May 2021 20:44:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229559AbhE2AoP (ORCPT ); Fri, 28 May 2021 20:44:15 -0400 Received: from mail-yb1-xb35.google.com (mail-yb1-xb35.google.com [IPv6:2607:f8b0:4864:20::b35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90C06C061574 for ; Fri, 28 May 2021 17:42:40 -0700 (PDT) Received: by mail-yb1-xb35.google.com with SMTP id i4so7913793ybe.2 for ; Fri, 28 May 2021 17:42:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3rNp2fDhgwLzO7RkwblP26djFafGfFHWnlzvqzrDqZI=; b=JtO5JzwuwvNHdC8HPItbi1wgfO3RerPFQ7UvmufO2tmaQDI3nUvBkIYWx5Qw8bL7rW b4R/92IAdFYe9t0DOQSSY8rJaEV1Fi+kVw0rE4AeeAcmlby0gXRdh3TF4wI40160vnf2 PM4NofM66n+oYEjXwjnacFNBwGBPs647mX62tA9asWVExbxHfNZOKhQj8+qxQpPMX7Ag 33AG08O8L6XT/+8F3Nxnzu+u8iwDJaRAxoIC2kVZAOauSV02MuM+3bH7mJZRgQdzuy4T zACJxjavU8c7+boCEYycqQAxILr6g0SBGpQMSDYoXnlxc9y02/uQd0880A/gaJTGkTQC K14A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3rNp2fDhgwLzO7RkwblP26djFafGfFHWnlzvqzrDqZI=; b=HI+k52jtWM0VYtrW35aosg+rEayU+YrCby5L3TMvkD4PoQ3m07cZAqimdb729VDwr7 1wePvkvB1ovsyK7mtkBRBtWVxSCdwBW/byPsbGM/ethyZNdV1h/zXfbR1At7WPIKWDr2 ERI26Rjiij9xotSHVxcsYlHOJbIdIea0Y7ExPfvKvIm1zFf/5ntbchVm/37RLrokdC3J v5B73YTG6r6yRSUiqacp0OhI61j/p092Gj3R+6rmYEQa4S6Nz430YQAyhrbaOLO7lUix bjfPCkk/uHDeNO4ziFk8ON7SUuGzLBzzVvxrYHdt1ir87dEFmeolgLgreOrp0Q/LJtgV GeVA== X-Gm-Message-State: AOAM531lcg4kDNUEZvFISCCWw/23zkKPm664KtwmiH/oU7sOnxzDCACu pmDjPrP7L3j8iEl7JadABlIzFmhcCwuXDKl/TXCZEQ== X-Google-Smtp-Source: ABdhPJzYj5znEzvjKe5Vxy6OnJiZYUmbPY/dv7trRPa7wnbyk+9j71wVOX/3HQa/ISUv61OHwbSbZPOaMLj3xMIiX2A= X-Received: by 2002:a25:74c6:: with SMTP id p189mr10271289ybc.84.1622248959537; Fri, 28 May 2021 17:42:39 -0700 (PDT) MIME-Version: 1.0 References: <20210428153542.2814175-1-Liam.Howlett@Oracle.com> <20210428153542.2814175-33-Liam.Howlett@Oracle.com> In-Reply-To: <20210428153542.2814175-33-Liam.Howlett@Oracle.com> From: Suren Baghdasaryan Date: Fri, 28 May 2021 17:42:28 -0700 Message-ID: Subject: Re: [PATCH 32/94] kernel/fork: Convert dup_mmap to use maple tree To: Liam Howlett Cc: "maple-tree@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , Song Liu , Davidlohr Bueso , "Paul E . McKenney" , Matthew Wilcox , Laurent Dufour , David Rientjes , Axel Rasmussen , Vlastimil Babka , Rik van Riel , Peter Zijlstra , Michel Lespinasse Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 28, 2021 at 8:36 AM Liam Howlett wrote: > > Use the maple tree iterator to duplicate the mm_struct trees. > > Signed-off-by: Liam R. Howlett > --- > include/linux/mm.h | 2 -- > include/linux/sched/mm.h | 3 +++ > kernel/fork.c | 24 +++++++++++++++++++----- > mm/mmap.c | 4 ---- > 4 files changed, 22 insertions(+), 11 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index e89bacfa9145..7f7dff6ad884 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2498,8 +2498,6 @@ extern bool arch_has_descending_max_zone_pfns(void); > /* nommu.c */ > extern atomic_long_t mmap_pages_allocated; > extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t); > -/* maple_tree */ > -void vma_store(struct mm_struct *mm, struct vm_area_struct *vma); > > /* interval_tree.c */ > void vma_interval_tree_insert(struct vm_area_struct *node, > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h > index e24b1fe348e3..76cab3aea6ab 100644 > --- a/include/linux/sched/mm.h > +++ b/include/linux/sched/mm.h > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > > /* > * Routines for handling mm_structs > @@ -67,11 +68,13 @@ static inline void mmdrop(struct mm_struct *mm) > */ > static inline void mmget(struct mm_struct *mm) > { > + mt_set_in_rcu(&mm->mm_mt); > atomic_inc(&mm->mm_users); > } > > static inline bool mmget_not_zero(struct mm_struct *mm) > { > + mt_set_in_rcu(&mm->mm_mt); Should you be calling mt_set_in_rcu() if atomic_inc_not_zero() failed? I don't think mmput() is called after mmget_not_zero() fails and mt_clear_in_rcu() will not be called. > return atomic_inc_not_zero(&mm->mm_users); > } > > diff --git a/kernel/fork.c b/kernel/fork.c > index c37abaf28eb9..832416ff613e 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -477,7 +477,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > struct vm_area_struct *mpnt, *tmp, *prev, **pprev; > struct rb_node **rb_link, *rb_parent; > int retval; > - unsigned long charge; > + unsigned long charge = 0; > + MA_STATE(old_mas, &oldmm->mm_mt, 0, 0); > + MA_STATE(mas, &mm->mm_mt, 0, 0); > LIST_HEAD(uf); > > uprobe_start_dup_mmap(); > @@ -511,7 +513,13 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > goto out; > > prev = NULL; > - for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { > + > + retval = mas_entry_count(&mas, oldmm->map_count); > + if (retval) > + goto fail_nomem; > + > + rcu_read_lock(); > + mas_for_each(&old_mas, mpnt, ULONG_MAX) { > struct file *file; > > if (mpnt->vm_flags & VM_DONTCOPY) { > @@ -525,7 +533,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > */ > if (fatal_signal_pending(current)) { > retval = -EINTR; > - goto out; > + goto loop_out; > } > if (mpnt->vm_flags & VM_ACCOUNT) { > unsigned long len = vma_pages(mpnt); > @@ -594,7 +602,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > rb_parent = &tmp->vm_rb; > > /* Link the vma into the MT */ > - vma_store(mm, tmp); > + mas.index = tmp->vm_start; > + mas.last = tmp->vm_end - 1; > + mas_store(&mas, tmp); > > mm->map_count++; > if (!(tmp->vm_flags & VM_WIPEONFORK)) > @@ -604,14 +614,17 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > tmp->vm_ops->open(tmp); > > if (retval) > - goto out; > + goto loop_out; > } > /* a new mm has just been created */ > retval = arch_dup_mmap(oldmm, mm); > +loop_out: > out: > + rcu_read_unlock(); > mmap_write_unlock(mm); > flush_tlb_mm(oldmm); > mmap_write_unlock(oldmm); > + mas_destroy(&mas); > dup_userfaultfd_complete(&uf); > fail_uprobe_end: > uprobe_end_dup_mmap(); > @@ -1092,6 +1105,7 @@ static inline void __mmput(struct mm_struct *mm) > { > VM_BUG_ON(atomic_read(&mm->mm_users)); > > + mt_clear_in_rcu(&mm->mm_mt); > uprobe_clear_state(mm); > exit_aio(mm); > ksm_exit(mm); > diff --git a/mm/mmap.c b/mm/mmap.c > index 929c2f9eb3f5..1bd43f4db28e 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -780,10 +780,6 @@ static inline void vma_mt_store(struct mm_struct *mm, struct vm_area_struct *vma > GFP_KERNEL); > } > > -void vma_store(struct mm_struct *mm, struct vm_area_struct *vma) { > - vma_mt_store(mm, vma); > -} > - > static void > __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, > struct vm_area_struct *prev, struct rb_node **rb_link, > -- > 2.30.2 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 X-Spam-Level: X-Spam-Status: No, score=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8104C4708E for ; Sat, 29 May 2021 00:42:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4F7AD613EB for ; Sat, 29 May 2021 00:42:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F7AD613EB Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D722C6B0036; Fri, 28 May 2021 20:42:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D1A436B006E; Fri, 28 May 2021 20:42:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 835E96B0070; Fri, 28 May 2021 20:42:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0171.hostedemail.com [216.40.44.171]) by kanga.kvack.org (Postfix) with ESMTP id 42ACD6B0036 for ; Fri, 28 May 2021 20:42:41 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B5D5C181AEF3E for ; Sat, 29 May 2021 00:42:40 +0000 (UTC) X-FDA: 78192418080.23.2FEC8DA Received: from mail-yb1-f176.google.com (mail-yb1-f176.google.com [209.85.219.176]) by imf13.hostedemail.com (Postfix) with ESMTP id 33D2CE000130 for ; Sat, 29 May 2021 00:42:31 +0000 (UTC) Received: by mail-yb1-f176.google.com with SMTP id p184so7857837yba.11 for ; Fri, 28 May 2021 17:42:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=3rNp2fDhgwLzO7RkwblP26djFafGfFHWnlzvqzrDqZI=; b=JtO5JzwuwvNHdC8HPItbi1wgfO3RerPFQ7UvmufO2tmaQDI3nUvBkIYWx5Qw8bL7rW b4R/92IAdFYe9t0DOQSSY8rJaEV1Fi+kVw0rE4AeeAcmlby0gXRdh3TF4wI40160vnf2 PM4NofM66n+oYEjXwjnacFNBwGBPs647mX62tA9asWVExbxHfNZOKhQj8+qxQpPMX7Ag 33AG08O8L6XT/+8F3Nxnzu+u8iwDJaRAxoIC2kVZAOauSV02MuM+3bH7mJZRgQdzuy4T zACJxjavU8c7+boCEYycqQAxILr6g0SBGpQMSDYoXnlxc9y02/uQd0880A/gaJTGkTQC K14A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=3rNp2fDhgwLzO7RkwblP26djFafGfFHWnlzvqzrDqZI=; b=CPM5Tfbf/WhMxV+vREY3OlPH2R+i7JO0ORUxlSmB2gpK93NA0n3DsrsiCl8wxAQGIb E5UkXpnnse7kJ9mbvxYiccpmqU7cuqKXTZwIzjuShcruItHvf0MlCtfJhW04PeAHJsrz BELaHXCKHqAy0aigWrwQxWL+auAfCjeWjgDhh9VK006Jp1Mi5NDmyYjU0RLWNLO87Er4 e/UgkNABs76iv++xR+niTtQ7jbt0n1adupqgYJCn0eCjIRWmZZgBRp6EE7REwpE40WNW ZEfZWo5oQ5kMb6I1xOCcdXW1fn4IgWniyTAbbILDzz/5msZG5odd/wIR55XZ1OzzrzKR 3YQg== X-Gm-Message-State: AOAM530a5bpMYhmm4U9XuX8nNHvChHR4p4oakgHV9Ro+RDttU312MrEl I+Zbu9HbA0RXVcUKM5J5O1U8GRXgW9YxxWmJYzodkg== X-Google-Smtp-Source: ABdhPJzYj5znEzvjKe5Vxy6OnJiZYUmbPY/dv7trRPa7wnbyk+9j71wVOX/3HQa/ISUv61OHwbSbZPOaMLj3xMIiX2A= X-Received: by 2002:a25:74c6:: with SMTP id p189mr10271289ybc.84.1622248959537; Fri, 28 May 2021 17:42:39 -0700 (PDT) MIME-Version: 1.0 References: <20210428153542.2814175-1-Liam.Howlett@Oracle.com> <20210428153542.2814175-33-Liam.Howlett@Oracle.com> In-Reply-To: <20210428153542.2814175-33-Liam.Howlett@Oracle.com> From: Suren Baghdasaryan Date: Fri, 28 May 2021 17:42:28 -0700 Message-ID: Subject: Re: [PATCH 32/94] kernel/fork: Convert dup_mmap to use maple tree To: Liam Howlett Cc: "maple-tree@lists.infradead.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , Song Liu , Davidlohr Bueso , "Paul E . McKenney" , Matthew Wilcox , Laurent Dufour , David Rientjes , Axel Rasmussen , Vlastimil Babka , Rik van Riel , Peter Zijlstra , Michel Lespinasse Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=JtO5Jzwu; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf13.hostedemail.com: domain of surenb@google.com designates 209.85.219.176 as permitted sender) smtp.mailfrom=surenb@google.com X-Stat-Signature: bbihdhbuenmqg9cj6zrfsrzmbbprporq X-Rspamd-Queue-Id: 33D2CE000130 X-Rspamd-Server: rspam02 X-HE-Tag: 1622248951-332022 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 28, 2021 at 8:36 AM Liam Howlett wrote: > > Use the maple tree iterator to duplicate the mm_struct trees. > > Signed-off-by: Liam R. Howlett > --- > include/linux/mm.h | 2 -- > include/linux/sched/mm.h | 3 +++ > kernel/fork.c | 24 +++++++++++++++++++----- > mm/mmap.c | 4 ---- > 4 files changed, 22 insertions(+), 11 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index e89bacfa9145..7f7dff6ad884 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2498,8 +2498,6 @@ extern bool arch_has_descending_max_zone_pfns(void); > /* nommu.c */ > extern atomic_long_t mmap_pages_allocated; > extern int nommu_shrink_inode_mappings(struct inode *, size_t, size_t); > -/* maple_tree */ > -void vma_store(struct mm_struct *mm, struct vm_area_struct *vma); > > /* interval_tree.c */ > void vma_interval_tree_insert(struct vm_area_struct *node, > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h > index e24b1fe348e3..76cab3aea6ab 100644 > --- a/include/linux/sched/mm.h > +++ b/include/linux/sched/mm.h > @@ -8,6 +8,7 @@ > #include > #include > #include > +#include > > /* > * Routines for handling mm_structs > @@ -67,11 +68,13 @@ static inline void mmdrop(struct mm_struct *mm) > */ > static inline void mmget(struct mm_struct *mm) > { > + mt_set_in_rcu(&mm->mm_mt); > atomic_inc(&mm->mm_users); > } > > static inline bool mmget_not_zero(struct mm_struct *mm) > { > + mt_set_in_rcu(&mm->mm_mt); Should you be calling mt_set_in_rcu() if atomic_inc_not_zero() failed? I don't think mmput() is called after mmget_not_zero() fails and mt_clear_in_rcu() will not be called. > return atomic_inc_not_zero(&mm->mm_users); > } > > diff --git a/kernel/fork.c b/kernel/fork.c > index c37abaf28eb9..832416ff613e 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -477,7 +477,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > struct vm_area_struct *mpnt, *tmp, *prev, **pprev; > struct rb_node **rb_link, *rb_parent; > int retval; > - unsigned long charge; > + unsigned long charge = 0; > + MA_STATE(old_mas, &oldmm->mm_mt, 0, 0); > + MA_STATE(mas, &mm->mm_mt, 0, 0); > LIST_HEAD(uf); > > uprobe_start_dup_mmap(); > @@ -511,7 +513,13 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > goto out; > > prev = NULL; > - for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { > + > + retval = mas_entry_count(&mas, oldmm->map_count); > + if (retval) > + goto fail_nomem; > + > + rcu_read_lock(); > + mas_for_each(&old_mas, mpnt, ULONG_MAX) { > struct file *file; > > if (mpnt->vm_flags & VM_DONTCOPY) { > @@ -525,7 +533,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > */ > if (fatal_signal_pending(current)) { > retval = -EINTR; > - goto out; > + goto loop_out; > } > if (mpnt->vm_flags & VM_ACCOUNT) { > unsigned long len = vma_pages(mpnt); > @@ -594,7 +602,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > rb_parent = &tmp->vm_rb; > > /* Link the vma into the MT */ > - vma_store(mm, tmp); > + mas.index = tmp->vm_start; > + mas.last = tmp->vm_end - 1; > + mas_store(&mas, tmp); > > mm->map_count++; > if (!(tmp->vm_flags & VM_WIPEONFORK)) > @@ -604,14 +614,17 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm, > tmp->vm_ops->open(tmp); > > if (retval) > - goto out; > + goto loop_out; > } > /* a new mm has just been created */ > retval = arch_dup_mmap(oldmm, mm); > +loop_out: > out: > + rcu_read_unlock(); > mmap_write_unlock(mm); > flush_tlb_mm(oldmm); > mmap_write_unlock(oldmm); > + mas_destroy(&mas); > dup_userfaultfd_complete(&uf); > fail_uprobe_end: > uprobe_end_dup_mmap(); > @@ -1092,6 +1105,7 @@ static inline void __mmput(struct mm_struct *mm) > { > VM_BUG_ON(atomic_read(&mm->mm_users)); > > + mt_clear_in_rcu(&mm->mm_mt); > uprobe_clear_state(mm); > exit_aio(mm); > ksm_exit(mm); > diff --git a/mm/mmap.c b/mm/mmap.c > index 929c2f9eb3f5..1bd43f4db28e 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -780,10 +780,6 @@ static inline void vma_mt_store(struct mm_struct *mm, struct vm_area_struct *vma > GFP_KERNEL); > } > > -void vma_store(struct mm_struct *mm, struct vm_area_struct *vma) { > - vma_mt_store(mm, vma); > -} > - > static void > __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, > struct vm_area_struct *prev, struct rb_node **rb_link, > -- > 2.30.2