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| author | Chuhong Yuan <hslester96@gmail.com> | 2019-08-08 15:18:26 +0800 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2019-08-21 12:41:43 +0200 |
| commit | 40e90656c13587c0826e8afeef3cebe585db2d2c (patch) | |
| tree | 0d733b4321ccc910b63fcb1990dd30f52725a242 | |
| parent | 3434caec5b70519ead87e7b66dbdc18e8dbaa506 (diff) | |
| download | linux-40e90656c13587c0826e8afeef3cebe585db2d2c.tar.bz2 | |
s390/mm: use refcount_t for refcount
Reference counters are preferred to use refcount_t instead of
atomic_t.
This is because the implementation of refcount_t can prevent
overflows and detect possible use-after-free.
So convert atomic_t ref counters to refcount_t.
Link: http://lkml.kernel.org/r/20190808071826.6649-1-hslester96@gmail.com
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
| -rw-r--r-- | arch/s390/include/asm/gmap.h | 4 | ||||
| -rw-r--r-- | arch/s390/mm/gmap.c | 10 |
2 files changed, 8 insertions, 6 deletions
diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index fcbd638fb9f4..37f96b6f0e61 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -9,6 +9,8 @@ #ifndef _ASM_S390_GMAP_H #define _ASM_S390_GMAP_H +#include <linux/refcount.h> + /* Generic bits for GMAP notification on DAT table entry changes. */ #define GMAP_NOTIFY_SHADOW 0x2 #define GMAP_NOTIFY_MPROT 0x1 @@ -46,7 +48,7 @@ struct gmap { struct radix_tree_root guest_to_host; struct radix_tree_root host_to_guest; spinlock_t guest_table_lock; - atomic_t ref_count; + refcount_t ref_count; unsigned long *table; unsigned long asce; unsigned long asce_end; diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 1e668b95e0c6..3770f12d9252 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -67,7 +67,7 @@ static struct gmap *gmap_alloc(unsigned long limit) INIT_RADIX_TREE(&gmap->host_to_rmap, GFP_ATOMIC); spin_lock_init(&gmap->guest_table_lock); spin_lock_init(&gmap->shadow_lock); - atomic_set(&gmap->ref_count, 1); + refcount_set(&gmap->ref_count, 1); page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER); if (!page) goto out_free; @@ -214,7 +214,7 @@ static void gmap_free(struct gmap *gmap) */ struct gmap *gmap_get(struct gmap *gmap) { - atomic_inc(&gmap->ref_count); + refcount_inc(&gmap->ref_count); return gmap; } EXPORT_SYMBOL_GPL(gmap_get); @@ -227,7 +227,7 @@ EXPORT_SYMBOL_GPL(gmap_get); */ void gmap_put(struct gmap *gmap) { - if (atomic_dec_return(&gmap->ref_count) == 0) + if (refcount_dec_and_test(&gmap->ref_count)) gmap_free(gmap); } EXPORT_SYMBOL_GPL(gmap_put); @@ -1594,7 +1594,7 @@ static struct gmap *gmap_find_shadow(struct gmap *parent, unsigned long asce, continue; if (!sg->initialized) return ERR_PTR(-EAGAIN); - atomic_inc(&sg->ref_count); + refcount_inc(&sg->ref_count); return sg; } return NULL; @@ -1682,7 +1682,7 @@ struct gmap *gmap_shadow(struct gmap *parent, unsigned long asce, } } } - atomic_set(&new->ref_count, 2); + refcount_set(&new->ref_count, 2); list_add(&new->list, &parent->children); if (asce & _ASCE_REAL_SPACE) { /* nothing to protect, return right away */ |