mm: abstract vma_expand() to use vma_merge_struct

The purpose of the vmg is to thread merge state through functions and
avoid egregious parameter lists.  We expand this to vma_expand(), which is
used for a number of merge cases.

Accordingly, adjust its callers, mmap_region() and relocate_vma_down(), to
use a vmg.

An added purpose of this change is the ability in a future commit to
perform all new VMA range merging using vma_expand().

Link: https://lkml.kernel.org/r/4bc8c9dbc9ca52452ef8e587b28fe555854ceb38.1725040657.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Bert Karwatzki <spasswolf@web.de>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index 3af8459e4e885b471882fe72c49433c914737231..2b3006efd3fbc82b18a3ea81c169fa227c7a4b9b 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1371,7 +1371,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
        struct ma_state mas_detach;
        struct maple_tree mt_detach;
        unsigned long end = addr + len;
-       unsigned long merge_start = addr, merge_end = end;
        bool writable_file_mapping = false;
        int error = -ENOMEM;
        VMA_ITERATOR(vmi, mm, addr);
@@ -1424,8 +1423,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
        /* Attempt to expand an old mapping */
        /* Check next */
        if (next && next->vm_start == end && can_vma_merge_before(&vmg)) {
-               merge_end = next->vm_end;
-               vma = next;
+               vmg.end = next->vm_end;
+               vma = vmg.vma = next;
                vmg.pgoff = next->vm_pgoff - pglen;
                /*
                 * We set this here so if we will merge with the previous VMA in
@@ -1438,15 +1437,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 
        /* Check prev */
        if (prev && prev->vm_end == addr && can_vma_merge_after(&vmg)) {
-               merge_start = prev->vm_start;
-               vma = prev;
+               vmg.start = prev->vm_start;
+               vma = vmg.vma = prev;
                vmg.pgoff = prev->vm_pgoff;
                vma_prev(&vmi); /* Equivalent to going to the previous range */
        }
 
        if (vma) {
                /* Actually expand, if possible */
-               if (!vma_expand(&vmi, vma, merge_start, merge_end, vmg.pgoff, next)) {
+               if (!vma_expand(&vmg)) {
                        khugepaged_enter_vma(vma, vm_flags);
                        goto expanded;
                }
@@ -2320,6 +2319,7 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
        unsigned long new_start = old_start - shift;
        unsigned long new_end = old_end - shift;
        VMA_ITERATOR(vmi, mm, new_start);
+       VMG_STATE(vmg, mm, &vmi, new_start, old_end, 0, vma->vm_pgoff);
        struct vm_area_struct *next;
        struct mmu_gather tlb;
 
@@ -2336,7 +2336,8 @@ int relocate_vma_down(struct vm_area_struct *vma, unsigned long shift)
        /*
         * cover the whole range: [new_start, old_end)
         */
-       if (vma_expand(&vmi, vma, new_start, old_end, vma->vm_pgoff, NULL))
+       vmg.vma = vma;
+       if (vma_expand(&vmg))
                return -ENOMEM;
 
        /*

diff --git a/mm/vma.c b/mm/vma.c
index 3284bb778c3dae7326275b54dbdf6f3ae6ead4e8..d1033dade70e367d3fd8b10c7132df39f8505676 100644 (file)
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -467,30 +467,25 @@ void validate_mm(struct mm_struct *mm)
 /*
  * vma_expand - Expand an existing VMA
  *
- * @vmi: The vma iterator
- * @vma: The vma to expand
- * @start: The start of the vma
- * @end: The exclusive end of the vma
- * @pgoff: The page offset of vma
- * @next: The current of next vma.
+ * @vmg: Describes a VMA expansion operation.
  *
- * Expand @vma to @start and @end.  Can expand off the start and end.  Will
- * expand over @next if it's different from @vma and @end == @next->vm_end.
- * Checking if the @vma can expand and merge with @next needs to be handled by
- * the caller.
+ * Expand @vma to vmg->start and vmg->end.  Can expand off the start and end.
+ * Will expand over vmg->next if it's different from vmg->vma and vmg->end ==
+ * vmg->next->vm_end.  Checking if the vmg->vma can expand and merge with
+ * vmg->next needs to be handled by the caller.
  *
  * Returns: 0 on success
  */
-int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
-              unsigned long start, unsigned long end, pgoff_t pgoff,
-              struct vm_area_struct *next)
+int vma_expand(struct vma_merge_struct *vmg)
 {
        struct vm_area_struct *anon_dup = NULL;
        bool remove_next = false;
+       struct vm_area_struct *vma = vmg->vma;
+       struct vm_area_struct *next = vmg->next;
        struct vma_prepare vp;
 
        vma_start_write(vma);
-       if (next && (vma != next) && (end == next->vm_end)) {
+       if (next && (vma != next) && (vmg->end == next->vm_end)) {
                int ret;
 
                remove_next = true;
@@ -503,21 +498,21 @@ int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
        init_multi_vma_prep(&vp, vma, NULL, remove_next ? next : NULL, NULL);
        /* Not merging but overwriting any part of next is not handled. */
        VM_WARN_ON(next && !vp.remove &&
-                 next != vma && end > next->vm_start);
+                 next != vma && vmg->end > next->vm_start);
        /* Only handles expanding */
-       VM_WARN_ON(vma->vm_start < start || vma->vm_end > end);
+       VM_WARN_ON(vma->vm_start < vmg->start || vma->vm_end > vmg->end);
 
        /* Note: vma iterator must be pointing to 'start' */
-       vma_iter_config(vmi, start, end);
-       if (vma_iter_prealloc(vmi, vma))
+       vma_iter_config(vmg->vmi, vmg->start, vmg->end);
+       if (vma_iter_prealloc(vmg->vmi, vma))
                goto nomem;
 
        vma_prepare(&vp);
-       vma_adjust_trans_huge(vma, start, end, 0);
-       vma_set_range(vma, start, end, pgoff);
-       vma_iter_store(vmi, vma);
+       vma_adjust_trans_huge(vma, vmg->start, vmg->end, 0);
+       vma_set_range(vma, vmg->start, vmg->end, vmg->pgoff);
+       vma_iter_store(vmg->vmi, vma);
 
-       vma_complete(&vp, vmi, vma->vm_mm);
+       vma_complete(&vp, vmg->vmi, vma->vm_mm);
        return 0;
 
 nomem:

diff --git a/mm/vma.h b/mm/vma.h
index e761713f855fe9ecdca3c172a41b43256f83c49d..218d884ff5ff952396866c99fc579ec233c1cf87 100644 (file)
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -128,10 +128,7 @@ void init_vma_prep(struct vma_prepare *vp,
 void vma_complete(struct vma_prepare *vp,
                  struct vma_iterator *vmi, struct mm_struct *mm);
 
-int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
-              unsigned long start, unsigned long end, pgoff_t pgoff,
-              struct vm_area_struct *next);
-
+int vma_expand(struct vma_merge_struct *vmg);
 int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma,
               unsigned long start, unsigned long end, pgoff_t pgoff);
 

diff --git a/tools/testing/vma/vma.c b/tools/testing/vma/vma.c
index 7a3f59186464217b78a4ba51420dc5f29ea877f0..f6c4706a861f5fac2722776e7e4594353081128b 100644 (file)
--- a/tools/testing/vma/vma.c
+++ b/tools/testing/vma/vma.c
@@ -121,8 +121,7 @@ static struct vm_area_struct *merge_existing(struct vma_merge_struct *vmg)
  */
 static int expand_existing(struct vma_merge_struct *vmg)
 {
-       return vma_expand(vmg->vmi, vmg->vma, vmg->start, vmg->end, vmg->pgoff,
-                         vmg->next);
+       return vma_expand(vmg);
 }
 
 /*