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s390/mm: use a single lock for the fields in mm_context_t

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The three locks 'lock', 'pgtable_lock' and 'gmap_lock' in the
mm_context_t can be reduced to a single lock.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2017-08-17 18:17:49 +02:00
parent 60f07c8ec5
commit f28a4b4ddf
4 changed files with 12 additions and 19 deletions
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5
arch/s390/include/asm/mmu.h
View File

@ -9,9 +9,7 @@ typedef struct {
cpumask_t cpu_attach_mask;
atomic_t flush_count;
unsigned int flush_mm;
spinlock_t pgtable_lock;
struct list_head pgtable_list;
spinlock_t gmap_lock;
struct list_head gmap_list;
unsigned long gmap_asce;
unsigned long asce;
@ -29,10 +27,7 @@ typedef struct {
#define INIT_MM_CONTEXT(name) \
.context.lock = __SPIN_LOCK_UNLOCKED(name.context.lock), \
.context.pgtable_lock = \
__SPIN_LOCK_UNLOCKED(name.context.pgtable_lock), \
.context.pgtable_list = LIST_HEAD_INIT(name.context.pgtable_list), \
.context.gmap_lock = __SPIN_LOCK_UNLOCKED(name.context.gmap_lock), \
.context.gmap_list = LIST_HEAD_INIT(name.context.gmap_list),
static inline int tprot(unsigned long addr)

2
arch/s390/include/asm/mmu_context.h
View File

@ -18,9 +18,7 @@ static inline int init_new_context(struct task_struct *tsk,
struct mm_struct *mm)
{
spin_lock_init(&mm->context.lock);
spin_lock_init(&mm->context.pgtable_lock);
INIT_LIST_HEAD(&mm->context.pgtable_list);
spin_lock_init(&mm->context.gmap_lock);
INIT_LIST_HEAD(&mm->context.gmap_list);
cpumask_clear(&mm->context.cpu_attach_mask);
atomic_set(&mm->context.flush_count, 0);

8
arch/s390/mm/gmap.c
View File

@ -100,14 +100,14 @@ struct gmap *gmap_create(struct mm_struct *mm, unsigned long limit)
if (!gmap)
return NULL;
gmap->mm = mm;
spin_lock(&mm->context.gmap_lock);
spin_lock(&mm->context.lock);
list_add_rcu(&gmap->list, &mm->context.gmap_list);
if (list_is_singular(&mm->context.gmap_list))
gmap_asce = gmap->asce;
else
gmap_asce = -1UL;
WRITE_ONCE(mm->context.gmap_asce, gmap_asce);
spin_unlock(&mm->context.gmap_lock);
spin_unlock(&mm->context.lock);
return gmap;
}
EXPORT_SYMBOL_GPL(gmap_create);
@ -248,7 +248,7 @@ void gmap_remove(struct gmap *gmap)
spin_unlock(&gmap->shadow_lock);
}
/* Remove gmap from the pre-mm list */
spin_lock(&gmap->mm->context.gmap_lock);
spin_lock(&gmap->mm->context.lock);
list_del_rcu(&gmap->list);
if (list_empty(&gmap->mm->context.gmap_list))
gmap_asce = 0;
@ -258,7 +258,7 @@ void gmap_remove(struct gmap *gmap)
else
gmap_asce = -1UL;
WRITE_ONCE(gmap->mm->context.gmap_asce, gmap_asce);
spin_unlock(&gmap->mm->context.gmap_lock);
spin_unlock(&gmap->mm->context.lock);
synchronize_rcu();
/* Put reference */
gmap_put(gmap);

16
arch/s390/mm/pgalloc.c
View File

@ -188,7 +188,7 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
/* Try to get a fragment of a 4K page as a 2K page table */
if (!mm_alloc_pgste(mm)) {
table = NULL;
spin_lock_bh(&mm->context.pgtable_lock);
spin_lock_bh(&mm->context.lock);
if (!list_empty(&mm->context.pgtable_list)) {
page = list_first_entry(&mm->context.pgtable_list,
struct page, lru);
@ -203,7 +203,7 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
list_del(&page->lru);
}
}
spin_unlock_bh(&mm->context.pgtable_lock);
spin_unlock_bh(&mm->context.lock);
if (table)
return table;
}
@ -227,9 +227,9 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
/* Return the first 2K fragment of the page */
atomic_set(&page->_mapcount, 1);
clear_table(table, _PAGE_INVALID, PAGE_SIZE);
spin_lock_bh(&mm->context.pgtable_lock);
spin_lock_bh(&mm->context.lock);
list_add(&page->lru, &mm->context.pgtable_list);
spin_unlock_bh(&mm->context.pgtable_lock);
spin_unlock_bh(&mm->context.lock);
}
return table;
}
@ -243,13 +243,13 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
if (!mm_alloc_pgste(mm)) {
/* Free 2K page table fragment of a 4K page */
bit = (__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
spin_lock_bh(&mm->context.pgtable_lock);
spin_lock_bh(&mm->context.lock);
mask = atomic_xor_bits(&page->_mapcount, 1U << bit);
if (mask & 3)
list_add(&page->lru, &mm->context.pgtable_list);
else
list_del(&page->lru);
spin_unlock_bh(&mm->context.pgtable_lock);
spin_unlock_bh(&mm->context.lock);
if (mask != 0)
return;
}
@ -275,13 +275,13 @@ void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
return;
}
bit = (__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
spin_lock_bh(&mm->context.pgtable_lock);
spin_lock_bh(&mm->context.lock);
mask = atomic_xor_bits(&page->_mapcount, 0x11U << bit);
if (mask & 3)
list_add_tail(&page->lru, &mm->context.pgtable_list);
else
list_del(&page->lru);
spin_unlock_bh(&mm->context.pgtable_lock);
spin_unlock_bh(&mm->context.lock);
table = (unsigned long *) (__pa(table) | (1U << bit));
tlb_remove_table(tlb, table);
}