ipc/shm, mm: drop do_vma_munmap()

The do_vma_munmap() wrapper existed for callers that didn't have a vma
iterator and needed to check the vma mseal status prior to calling the
underlying munmap().  All callers now use a vma iterator and since the
mseal check has been moved to do_vmi_align_munmap() and the vmas are
aligned, this function can just be called instead.

do_vmi_align_munmap() can no longer be static as ipc/shm is using it and
it is exported via the mm.h header.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Liam R. Howlett <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Cc: Bert Karwatzki <[email protected]>
Cc: Jeff Xu <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Paul Moore <[email protected]>
Cc: Sidhartha Kumar <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6f6053d7ea6f5c921aede242016f6783de85e606..b0ff06d18c71fac66acd1d1dd5cf2d46a62a5c01 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3287,14 +3287,14 @@ extern unsigned long do_mmap(struct file *file, unsigned long addr,
 extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
                         unsigned long start, size_t len, struct list_head *uf,
                         bool unlock);
+int do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
+                   struct mm_struct *mm, unsigned long start,
+                   unsigned long end, struct list_head *uf, bool unlock);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t,
                     struct list_head *uf);
 extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior);
 
 #ifdef CONFIG_MMU
-extern int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
-                        unsigned long start, unsigned long end,
-                        struct list_head *uf, bool unlock);
 extern int __mm_populate(unsigned long addr, unsigned long len,
                         int ignore_errors);
 static inline void mm_populate(unsigned long addr, unsigned long len)

diff --git a/ipc/shm.c b/ipc/shm.c
index 3e3071252dac65350588cd3eb04b84f80a38411b..99564c87008408b649f1f7f6733d30d2913765d2 100644 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1778,8 +1778,8 @@ long ksys_shmdt(char __user *shmaddr)
                         */
                        file = vma->vm_file;
                        size = i_size_read(file_inode(vma->vm_file));
-                       do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
-                                     NULL, false);
+                       do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start,
+                                           vma->vm_end, NULL, false);
                        /*
                         * We discovered the size of the shm segment, so
                         * break out of here and fall through to the next
@@ -1803,8 +1803,8 @@ long ksys_shmdt(char __user *shmaddr)
                if ((vma->vm_ops == &shm_vm_ops) &&
                    ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
                    (vma->vm_file == file)) {
-                       do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
-                                     NULL, false);
+                       do_vmi_align_munmap(&vmi, vma, mm, vma->vm_start,
+                                           vma->vm_end, NULL, false);
                }
 
                vma = vma_next(&vmi);

diff --git a/mm/mmap.c b/mm/mmap.c
index 4faadc54e89db953eb4ba47f0fba090f7a06bc56..6485f2300692fd64e099fc58e76fb2474996cc50 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -169,11 +169,12 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
                        goto out; /* mapping intersects with an existing non-brk vma. */
                /*
                 * mm->brk must be protected by write mmap_lock.
-                * do_vma_munmap() will drop the lock on success,  so update it
-                * before calling do_vma_munmap().
+                * do_vmi_align_munmap() will drop the lock on success,  so
+                * update it before calling do_vma_munmap().
                 */
                mm->brk = brk;
-               if (do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true))
+               if (do_vmi_align_munmap(&vmi, brkvma, mm, newbrk, oldbrk, &uf,
+                                       /* unlock = */ true))
                        goto out;
 
                goto success_unlocked;
@@ -1479,9 +1480,9 @@ cannot_expand:
                vma->vm_file = get_file(file);
                /*
                 * call_mmap() may map PTE, so ensure there are no existing PTEs
-                * call the vm_ops close function if one exists.
+                * and call the vm_ops close function if one exists.
                 */
-               vms_clean_up_area(&vms, &mas_detach, true);
+               vms_clean_up_area(&vms, &mas_detach);
                error = call_mmap(file, vma);
                if (error)
                        goto unmap_and_free_vma;
@@ -1744,28 +1745,6 @@ out:
        return ret;
 }
 
-/*
- * do_vma_munmap() - Unmap a full or partial vma.
- * @vmi: The vma iterator pointing at the vma
- * @vma: The first vma to be munmapped
- * @start: the start of the address to unmap
- * @end: The end of the address to unmap
- * @uf: The userfaultfd list_head
- * @unlock: Drop the lock on success
- *
- * unmaps a VMA mapping when the vma iterator is already in position.
- * Does not handle alignment.
- *
- * Return: 0 on success drops the lock of so directed, error on failure and will
- * still hold the lock.
- */
-int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
-               unsigned long start, unsigned long end, struct list_head *uf,
-               bool unlock)
-{
-       return do_vmi_align_munmap(vmi, vma, vma->vm_mm, start, end, uf, unlock);
-}
-
 /*
  * do_brk_flags() - Increase the brk vma if the flags match.
  * @vmi: The vma iterator

diff --git a/mm/vma.c b/mm/vma.c
index d2d71d659d1e6f480975fec9da863c69756a525d..713b2196d351a44f19fce1792f1e60068d5a1d56 100644 (file)
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -658,8 +658,8 @@ static inline void vms_clear_ptes(struct vma_munmap_struct *vms,
         */
        mas_set(mas_detach, 1);
        lru_add_drain();
-       tlb_gather_mmu(&tlb, vms->mm);
-       update_hiwater_rss(vms->mm);
+       tlb_gather_mmu(&tlb, vms->vma->vm_mm);
+       update_hiwater_rss(vms->vma->vm_mm);
        unmap_vmas(&tlb, mas_detach, vms->vma, vms->start, vms->end,
                   vms->vma_count, mm_wr_locked);
 
@@ -672,14 +672,14 @@ static inline void vms_clear_ptes(struct vma_munmap_struct *vms,
 }
 
 void vms_clean_up_area(struct vma_munmap_struct *vms,
-               struct ma_state *mas_detach, bool mm_wr_locked)
+               struct ma_state *mas_detach)
 {
        struct vm_area_struct *vma;
 
        if (!vms->nr_pages)
                return;
 
-       vms_clear_ptes(vms, mas_detach, mm_wr_locked);
+       vms_clear_ptes(vms, mas_detach, true);
        mas_set(mas_detach, 0);
        mas_for_each(mas_detach, vma, ULONG_MAX)
                if (vma->vm_ops && vma->vm_ops->close)
@@ -702,7 +702,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
        struct vm_area_struct *vma;
        struct mm_struct *mm;
 
-       mm = vms->mm;
+       mm = current->mm;
        mm->map_count -= vms->vma_count;
        mm->locked_vm -= vms->locked_vm;
        if (vms->unlock)
@@ -770,7 +770,7 @@ int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
                 * its limit temporarily, to help free resources as expected.
                 */
                if (vms->end < vms->vma->vm_end &&
-                   vms->mm->map_count >= sysctl_max_map_count)
+                   vms->vma->vm_mm->map_count >= sysctl_max_map_count)
                        goto map_count_exceeded;
 
                /* Don't bother splitting the VMA if we can't unmap it anyway */

diff --git a/mm/vma.h b/mm/vma.h
index 37b4b5d00b995f4a5686b4c840a8588fa8d9d6d8..b59d470cc223f8bb9c3510bf7c11472a8f048004 100644 (file)
--- a/mm/vma.h
+++ b/mm/vma.h
@@ -31,7 +31,6 @@ struct unlink_vma_file_batch {
  */
 struct vma_munmap_struct {
        struct vma_iterator *vmi;
-       struct mm_struct *mm;
        struct vm_area_struct *vma;     /* The first vma to munmap */
        struct vm_area_struct *prev;    /* vma before the munmap area */
        struct vm_area_struct *next;    /* vma after the munmap area */
@@ -114,7 +113,6 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms,
                unsigned long start, unsigned long end, struct list_head *uf,
                bool unlock)
 {
-       vms->mm = current->mm;
        vms->vmi = vmi;
        vms->vma = vma;
        if (vma) {
@@ -142,7 +140,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
                struct ma_state *mas_detach);
 
 void vms_clean_up_area(struct vma_munmap_struct *vms,
-               struct ma_state *mas_detach, bool mm_wr_locked);
+               struct ma_state *mas_detach);
 
 /*
  * reattach_vmas() - Undo any munmap work and free resources