linux-kernel - [PATCH v4 63/66] i915: Use the VMA iterator

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Message-ID: <20211201142918.921493-64-Liam.Howlett@oracle.com>
Date:   Wed, 1 Dec 2021 14:30:27 +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 63/66] i915: Use the VMA iterator

From: "Matthew Wilcox (Oracle)" <willy@...radead.org>

Replace the O(n.log(n)) loop with an O(n) loop.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 3173c9f9a040..39960973c130 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -425,12 +425,11 @@ static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
 static int
 probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len)
 {
-	const unsigned long end = addr + len;
+	VMA_ITERATOR(vmi, mm, addr);
 	struct vm_area_struct *vma;
-	int ret = -EFAULT;
 
 	mmap_read_lock(mm);
-	for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
+	for_each_vma_range(vmi, vma, addr + len) {
 		/* Check for holes, note that we also update the addr below */
 		if (vma->vm_start > addr)
 			break;
@@ -438,16 +437,13 @@ probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len)
 		if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
 			break;
 
-		if (vma->vm_end >= end) {
-			ret = 0;
-			break;
-		}
-
 		addr = vma->vm_end;
 	}
 	mmap_read_unlock(mm);
 
-	return ret;
+	if (vma)
+		return -EFAULT;
+	return 0;
 }
 
 /*
-- 
2.30.2