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[S390] fix list corruption in gmap reverse mapping

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This introduces locking via mm->page_table_lock to protect
the rmap list for guest mappings from being corrupted by concurrent
operations.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Carsten Otte 2011-10-30 15:17:01 +01:00 committed by Martin Schwidefsky
parent a9162f238a
commit cc772456ac
1 changed files with 9 additions and 0 deletions
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9
arch/s390/mm/pgtable.c
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@ -222,6 +222,7 @@ void gmap_free(struct gmap *gmap)
/* Free all segment & region tables. */
down_read(&gmap->mm->mmap_sem);
spin_lock(&gmap->mm->page_table_lock);
list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
table = (unsigned long *) page_to_phys(page);
if ((*table & _REGION_ENTRY_TYPE_MASK) == 0)
@ -230,6 +231,7 @@ void gmap_free(struct gmap *gmap)
gmap_unlink_segment(gmap, table);
__free_pages(page, ALLOC_ORDER);
}
spin_unlock(&gmap->mm->page_table_lock);
up_read(&gmap->mm->mmap_sem);
list_del(&gmap->list);
kfree(gmap);
@ -300,6 +302,7 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
flush = 0;
down_read(&gmap->mm->mmap_sem);
spin_lock(&gmap->mm->page_table_lock);
for (off = 0; off < len; off += PMD_SIZE) {
/* Walk the guest addr space page table */
table = gmap->table + (((to + off) >> 53) & 0x7ff);
@ -321,6 +324,7 @@ int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len)
*table = _SEGMENT_ENTRY_INV;
}
out:
spin_unlock(&gmap->mm->page_table_lock);
up_read(&gmap->mm->mmap_sem);
if (flush)
gmap_flush_tlb(gmap);
@ -351,6 +355,7 @@ int gmap_map_segment(struct gmap *gmap, unsigned long from,
flush = 0;
down_read(&gmap->mm->mmap_sem);
spin_lock(&gmap->mm->page_table_lock);
for (off = 0; off < len; off += PMD_SIZE) {
/* Walk the gmap address space page table */
table = gmap->table + (((to + off) >> 53) & 0x7ff);
@ -374,12 +379,14 @@ int gmap_map_segment(struct gmap *gmap, unsigned long from,
flush |= gmap_unlink_segment(gmap, table);
*table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off);
}
spin_unlock(&gmap->mm->page_table_lock);
up_read(&gmap->mm->mmap_sem);
if (flush)
gmap_flush_tlb(gmap);
return 0;
out_unmap:
spin_unlock(&gmap->mm->page_table_lock);
up_read(&gmap->mm->mmap_sem);
gmap_unmap_segment(gmap, to, len);
return -ENOMEM;
@ -446,7 +453,9 @@ unsigned long gmap_fault(unsigned long address, struct gmap *gmap)
page = pmd_page(*pmd);
mp = (struct gmap_pgtable *) page->index;
rmap->entry = table;
spin_lock(&mm->page_table_lock);
list_add(&rmap->list, &mp->mapper);
spin_unlock(&mm->page_table_lock);
/* Set gmap segment table entry to page table. */
*table = pmd_val(*pmd) & PAGE_MASK;
return vmaddr | (address & ~PMD_MASK);