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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, Liam.Howlett@Oracle.com,
	linux-mm@kvack.org, mm-commits@vger.kernel.org,
	torvalds@linux-foundation.org
Subject: [patch 11/40] mm/mmap: add inline munmap_vma_range() for code readability
Date: Sat, 17 Oct 2020 16:14:09 -0700
Message-ID: <20201017231409.Qiho8zkqA%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201017161314.88890b87fae7446ccc13c902@linux-foundation.org>

From: "Liam R. Howlett" <Liam.Howlett@Oracle.com>
Subject: mm/mmap: add inline munmap_vma_range() for code readability

There are two locations that have a block of code for munmapping a vma
range.  Change those two locations to use a function and add meaningful
comments about what happens to the arguments, which was unclear in the
previous code.

Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap.c |   48 +++++++++++++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 15 deletions(-)

--- a/mm/mmap.c~mm-mmap-add-inline-munmap_vma_range-for-code-readability
+++ a/mm/mmap.c
@@ -575,6 +575,33 @@ static inline struct vm_area_struct *vma
 
 	return vma->vm_next;
 }
+
+/*
+ * munmap_vma_range() - munmap VMAs that overlap a range.
+ * @mm: The mm struct
+ * @start: The start of the range.
+ * @len: The length of the range.
+ * @pprev: pointer to the pointer that will be set to previous vm_area_struct
+ * @rb_link: the rb_node
+ * @rb_parent: the parent rb_node
+ *
+ * Find all the vm_area_struct that overlap from @start to
+ * @end and munmap them.  Set @pprev to the previous vm_area_struct.
+ *
+ * Returns: -ENOMEM on munmap failure or 0 on success.
+ */
+static inline int
+munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
+		 struct vm_area_struct **pprev, struct rb_node ***link,
+		 struct rb_node **parent, struct list_head *uf)
+{
+
+	while (find_vma_links(mm, start, start + len, pprev, link, parent))
+		if (do_munmap(mm, start, len, uf))
+			return -ENOMEM;
+
+	return 0;
+}
 static unsigned long count_vma_pages_range(struct mm_struct *mm,
 		unsigned long addr, unsigned long end)
 {
@@ -1721,13 +1748,9 @@ unsigned long mmap_region(struct file *f
 			return -ENOMEM;
 	}
 
-	/* Clear old maps */
-	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
-			      &rb_parent)) {
-		if (do_munmap(mm, addr, len, uf))
-			return -ENOMEM;
-	}
-
+	/* Clear old maps, set up prev, rb_link, rb_parent, and uf */
+	if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+		return -ENOMEM;
 	/*
 	 * Private writable mapping: check memory availability
 	 */
@@ -3063,14 +3086,9 @@ static int do_brk_flags(unsigned long ad
 	if (error)
 		return error;
 
-	/*
-	 * Clear old maps.  this also does some error checking for us
-	 */
-	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
-			      &rb_parent)) {
-		if (do_munmap(mm, addr, len, uf))
-			return -ENOMEM;
-	}
+	/* Clear old maps, set up prev, rb_link, rb_parent, and uf */
+	if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))
+		return -ENOMEM;
 
 	/* Check against address space limits *after* clearing old maps... */
 	if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))
_

  parent reply index

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-17 23:13 incoming Andrew Morton
2020-10-17 23:13 ` [patch 01/40] ia64: fix build error with !COREDUMP Andrew Morton
2020-10-17 23:13 ` [patch 02/40] mm, memcg: rework remote charging API to support nesting Andrew Morton
2020-10-17 23:13 ` [patch 03/40] mm: kmem: move memcg_kmem_bypass() calls to get_mem/obj_cgroup_from_current() Andrew Morton
2020-10-17 23:13 ` [patch 04/40] mm: kmem: remove redundant checks from get_obj_cgroup_from_current() Andrew Morton
2020-10-17 23:13 ` [patch 05/40] mm: kmem: prepare remote memcg charging infra for interrupt contexts Andrew Morton
2020-10-17 23:13 ` [patch 06/40] mm: kmem: enable kernel memcg accounting from " Andrew Morton
2020-10-17 23:13 ` [patch 07/40] mm/memory-failure: remove a wrapper for alloc_migration_target() Andrew Morton
2020-10-17 23:14 ` [patch 08/40] mm/memory_hotplug: " Andrew Morton
2020-10-17 23:14 ` [patch 09/40] mm/migrate: avoid possible unnecessary process right check in kernel_move_pages() Andrew Morton
2020-10-17 23:14 ` [patch 10/40] mm/mmap: add inline vma_next() for readability of mmap code Andrew Morton
2020-10-17 23:14 ` Andrew Morton [this message]
2020-10-17 23:14 ` [patch 12/40] mm/gup_benchmark: take the mmap lock around GUP Andrew Morton
2020-10-17 23:14 ` [patch 13/40] binfmt_elf: take the mmap lock around find_extend_vma() Andrew Morton
2020-10-17 23:14 ` [patch 14/40] mm/gup: assert that the mmap lock is held in __get_user_pages() Andrew Morton
2020-10-17 23:14 ` [patch 15/40] mm/gup_benchmark: rename to mm/gup_test Andrew Morton
2020-10-17 23:14 ` [patch 16/40] selftests/vm: use a common gup_test.h Andrew Morton
2020-10-17 23:14 ` [patch 17/40] selftests/vm: rename run_vmtests --> run_vmtests.sh Andrew Morton
2020-10-17 23:14 ` [patch 18/40] selftests/vm: minor cleanup: Makefile and gup_test.c Andrew Morton
2020-10-17 23:14 ` [patch 19/40] selftests/vm: only some gup_test items are really benchmarks Andrew Morton
2020-10-17 23:14 ` [patch 20/40] selftests/vm: gup_test: introduce the dump_pages() sub-test Andrew Morton
2020-10-17 23:14 ` [patch 21/40] selftests/vm: run_vmtests.sh: update and clean up gup_test invocation Andrew Morton
2020-10-17 23:14 ` [patch 22/40] selftests/vm: hmm-tests: remove the libhugetlbfs dependency Andrew Morton
2020-10-17 23:14 ` [patch 23/40] selftests/vm: 10x speedup for hmm-tests Andrew Morton
2020-10-17 23:14 ` [patch 24/40] mm/madvise: pass mm to do_madvise Andrew Morton
2020-10-17 23:14 ` [patch 25/40] pid: move pidfd_get_pid() to pid.c Andrew Morton
2020-10-17 23:14 ` [patch 26/40] mm/madvise: introduce process_madvise() syscall: an external memory hinting API Andrew Morton
2020-10-17 23:15 ` [patch 27/40] mm: update the documentation for vfree Andrew Morton
2020-10-17 23:15 ` [patch 28/40] mm: add a VM_MAP_PUT_PAGES flag for vmap Andrew Morton
2020-10-17 23:15 ` [patch 29/40] mm: add a vmap_pfn function Andrew Morton
2020-10-17 23:15 ` [patch 30/40] mm: allow a NULL fn callback in apply_to_page_range Andrew Morton
2020-10-17 23:15 ` [patch 31/40] zsmalloc: switch from alloc_vm_area to get_vm_area Andrew Morton
2020-10-17 23:15 ` [patch 32/40] drm/i915: use vmap in shmem_pin_map Andrew Morton
2020-10-17 23:15 ` [patch 33/40] drm/i915: stop using kmap in i915_gem_object_map Andrew Morton
2020-10-17 23:15 ` [patch 34/40] drm/i915: use vmap " Andrew Morton
2020-10-17 23:15 ` [patch 35/40] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv Andrew Morton
2020-10-17 23:15 ` [patch 36/40] x86/xen: open code alloc_vm_area in arch_gnttab_valloc Andrew Morton
2020-10-17 23:15 ` [patch 37/40] mm: remove alloc_vm_area Andrew Morton
2020-10-17 23:15 ` [patch 38/40] mm: cleanup the gfp_mask handling in __vmalloc_area_node Andrew Morton
2020-10-17 23:15 ` [patch 39/40] mm: remove the filename in the top of file comment in vmalloc.c Andrew Morton
2020-10-17 23:15 ` [patch 40/40] mm: remove duplicate include statement in mmu.c Andrew Morton

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