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Date: Tue, 12 Jan 2021 11:11:41 -0500 From: "Liam R. Howlett" <Liam.Howlett@...cle.com> To: maple-tree@...ts.infradead.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org Cc: Andrew Morton <akpm@...gle.com>, Song Liu <songliubraving@...com>, Davidlohr Bueso <dave@...olabs.net>, "Paul E . McKenney" <paulmck@...nel.org>, Matthew Wilcox <willy@...radead.org>, Jerome Glisse <jglisse@...hat.com>, David Rientjes <rientjes@...gle.com>, Axel Rasmussen <axelrasmussen@...gle.com>, Suren Baghdasaryan <surenb@...gle.com>, Vlastimil Babka <vbabka@...e.cz>, Rik van Riel <riel@...riel.com>, Peter Zijlstra <peterz@...radead.org> Subject: [PATCH v2 11/70] kernel/fork: Convert dup_mmap to use maple tree Use the maple tree iterator to duplicate the mm_struct trees. Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com> --- include/linux/sched/mm.h | 3 +++ kernel/fork.c | 22 +++++++++++++++++----- 2 files changed, 20 insertions(+), 5 deletions(-) diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index d5ece7a9a403f..919e2e44b764e 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -8,6 +8,7 @@ #include <linux/mm_types.h> #include <linux/gfp.h> #include <linux/sync_core.h> +#include <linux/maple_tree.h> /* * 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); return atomic_inc_not_zero(&mm->mm_users); } diff --git a/kernel/fork.c b/kernel/fork.c index 8c7273b0d4b77..8fcbd970666c3 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -472,7 +472,9 @@ 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(); @@ -506,7 +508,12 @@ 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; + + mas_for_each(&old_mas, mpnt, ULONG_MAX) { struct file *file; if (mpnt->vm_flags & VM_DONTCOPY) { @@ -520,7 +527,7 @@ 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); @@ -589,7 +596,9 @@ 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)) @@ -599,14 +608,16 @@ 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: 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(); @@ -1076,6 +1087,7 @@ 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); -- 2.28.0
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