linux-kernel - [PATCH v4 57/66] mm/mprotect: Use maple tree navigation instead of vma linked list

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Date:   Wed, 1 Dec 2021 14:30:15 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     "maple-tree@...ts.infradead.org" <maple-tree@...ts.infradead.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>
CC:     Song Liu <songliubraving@...com>,
        Davidlohr Bueso <dave@...olabs.net>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        Laurent Dufour <ldufour@...ux.ibm.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>,
        Michel Lespinasse <walken.cr@...il.com>,
        Jerome Glisse <jglisse@...hat.com>,
        Minchan Kim <minchan@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Rom Lemarchand <romlem@...gle.com>,
        Liam Howlett <liam.howlett@...cle.com>
Subject: [PATCH v4 57/66] mm/mprotect: Use maple tree navigation instead of
 vma linked list

From: "Liam R. Howlett" <Liam.Howlett@...cle.com>

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 mm/mprotect.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index e552f5e0ccbd..7af58fd467c6 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -528,6 +528,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	const int grows = prot & (PROT_GROWSDOWN|PROT_GROWSUP);
 	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
 				(prot & PROT_READ);
+	MA_STATE(mas, &current->mm->mm_mt, start, start);
 
 	start = untagged_addr(start);
 
@@ -559,7 +560,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
 		goto out;
 
-	vma = find_vma(current->mm, start);
+	vma = mas_find(&mas, ULONG_MAX);
 	error = -ENOMEM;
 	if (!vma)
 		goto out;
@@ -585,7 +586,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	if (start > vma->vm_start)
 		prev = vma;
 	else
-		prev = vma->vm_prev;
+		prev = mas_prev(&mas, 0);
 
 	for (nstart = start ; ; ) {
 		unsigned long mask_off_old_flags;
@@ -647,7 +648,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 		if (nstart >= end)
 			goto out;
 
-		vma = prev->vm_next;
+		vma = find_vma(current->mm, prev->vm_end);
 		if (!vma || vma->vm_start != nstart) {
 			error = -ENOMEM;
 			goto out;
-- 
2.30.2