Commit 182ea1d7 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

coredump: remove vma linked list walk 

Use the Maple Tree iterator instead.  This is too complicated for the VMA
iterator to handle, so let's open-code it for now.  If this turns out to
be a common pattern, we can migrate it to common code.

Link: https://lkml.kernel.org/r/20220906194824.2110408-41-Liam.Howlett@oracle.com


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: default avatarYu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent cbd43755

fs/coredump.c

+12 −22
Original line number Diff line number Diff line
@@ -1072,30 +1072,20 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma, 
	return vma->vm_end - vma->vm_start;

}



static struct vm_area_struct *first_vma(struct task_struct *tsk,

					struct vm_area_struct *gate_vma)

{

	struct vm_area_struct *ret = tsk->mm->mmap;



	if (ret)

		return ret;

	return gate_vma;

}



/*

 * Helper function for iterating across a vma list.  It ensures that the caller

 * will visit `gate_vma' prior to terminating the search.

 */

static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,

static struct vm_area_struct *coredump_next_vma(struct ma_state *mas,

				       struct vm_area_struct *vma,

				       struct vm_area_struct *gate_vma)

{

	struct vm_area_struct *ret;



	ret = this_vma->vm_next;

	if (ret)

		return ret;

	if (this_vma == gate_vma)

	if (gate_vma && (vma == gate_vma))

		return NULL;



	vma = mas_next(mas, ULONG_MAX);

	if (vma)

		return vma;

	return gate_vma;

}
@@ -1119,9 +1109,10 @@ static void free_vma_snapshot(struct coredump_params *cprm) 
 */

static bool dump_vma_snapshot(struct coredump_params *cprm)

{

	struct vm_area_struct *vma, *gate_vma;

	struct vm_area_struct *gate_vma, *vma = NULL;

	struct mm_struct *mm = current->mm;

	int i;

	MA_STATE(mas, &mm->mm_mt, 0, 0);

	int i = 0;



	/*

	 * Once the stack expansion code is fixed to not change VMA bounds
@@ -1141,8 +1132,7 @@ static bool dump_vma_snapshot(struct coredump_params *cprm) 
		return false;

	}



	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;

			vma = next_vma(vma, gate_vma), i++) {

	while ((vma = coredump_next_vma(&mas, vma, gate_vma)) != NULL) {

		struct core_vma_metadata *m = cprm->vma_meta + i;



		m->start = vma->vm_start;
@@ -1150,10 +1140,10 @@ static bool dump_vma_snapshot(struct coredump_params *cprm) 
		m->flags = vma->vm_flags;

		m->dump_size = vma_dump_size(vma, cprm->mm_flags);

		m->pgoff = vma->vm_pgoff;



		m->file = vma->vm_file;

		if (m->file)

			get_file(m->file);

		i++;

	}



	mmap_write_unlock(mm);