Commit 63fc66f5 authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Andrew Morton
Browse files

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/20240830040101.822209-19-Liam.Howlett@oracle.com


Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
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: Mark Brown <broonie@kernel.org>
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>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 13d77e01

include/linux/mm.h

+3 −3
Original line number Diff line number Diff line
@@ -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)

ipc/shm.c

+4 −4
Original line number Diff line number Diff line
@@ -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);

mm/mmap.c

+6 −27
Original line number Diff line number Diff line
@@ -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 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 
		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 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 
	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

mm/vma.c

+6 −6
Original line number Diff line number Diff line
@@ -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 */

mm/vma.h

+1 −3
Original line number Diff line number Diff line
@@ -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