linux-kernel - [PATCH v3 23/66] mm/mmap: Change do_brk_munmap() to use do_mas_align

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Date:   Tue, 5 Oct 2021 01:30:46 +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>,
        David Hildenbrand <david@...hat.com>,
        Douglas Gilbert <dgilbert@...erlog.com>
CC:     Song Liu <songliubraving@...com>,
        Davidlohr Bueso <dave@...olabs.net>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        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 v3 23/66] mm/mmap: Change do_brk_munmap() to use
 do_mas_align_munmap()

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

do_brk_munmap() has already aligned the address and has a maple tree
state to be used.  Use the new do_mas_align_munmap() to avoid
unnecessary alignment and error checks.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 mm/mmap.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 25fcdf2ff739..56da5a23e293 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3009,13 +3009,16 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
 	struct mm_struct *mm = vma->vm_mm;
 	struct vm_area_struct unmap;
 	unsigned long unmap_pages;
-	int ret = 1;
+	int ret;
 
 	arch_unmap(mm, newbrk, oldbrk);
 
-	if (likely(vma->vm_start >= newbrk)) { // remove entire mapping(s)
+	if (likely((vma->vm_end < oldbrk) ||
+		   ((vma->vm_start == newbrk) && (vma->vm_end == oldbrk)))) {
+		// remove entire mapping(s)
 		mas_lock(mas);
-		ret = do_mas_munmap(mas, mm, newbrk, oldbrk-newbrk, uf, true);
+		ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf,
+					  true);
 		if (ret != 1)
 			mas_unlock(mas);
 		goto munmap_full_vma;
-- 
2.30.2