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| author |   Chuhong Yuan <hslester96@gmail.com> | 2019-08-08 15:18:17 +0800 |
|---|---|---|
| committer |   Vasily Gorbik <gor@linux.ibm.com> | 2019-08-21 12:41:43 +0200 |
| commit | 3434caec5b70519ead87e7b66dbdc18e8dbaa506 (patch) | |
| tree | d1664307d7535e986df81f880aee8f9edb6fd685 /arch/s390/mm/extmem.c | |
| parent | s390/pci: PCI_IOV_RESOURCES loop refactoring in zpci_map_resources (diff) | |
| download | linux-dev-3434caec5b70519ead87e7b66dbdc18e8dbaa506.tar.xz linux-dev-3434caec5b70519ead87e7b66dbdc18e8dbaa506.zip | |
s390/extmem: 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/20190808071817.6595-1-hslester96@gmail.com
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/s390/mm/extmem.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c index 0b5622714c12..fd0dae9d10f4 100644 --- a/arch/s390/mm/extmem.c +++ b/arch/s390/mm/extmem.c @@ -19,6 +19,7 @@ #include <linux/memblock.h> #include <linux/ctype.h> #include <linux/ioport.h> +#include <linux/refcount.h> #include <asm/diag.h> #include <asm/page.h> #include <asm/pgtable.h> @@ -64,7 +65,7 @@ struct dcss_segment { char res_name[16]; unsigned long start_addr; unsigned long end; - atomic_t ref_count; + refcount_t ref_count; int do_nonshared; unsigned int vm_segtype; struct qrange range[6]; @@ -362,7 +363,7 @@ __segment_load (char *name, int do_nonshared, unsigned long *addr, unsigned long seg->start_addr = start_addr; seg->end = end_addr; seg->do_nonshared = do_nonshared; - atomic_set(&seg->ref_count, 1); + refcount_set(&seg->ref_count, 1); list_add(&seg->list, &dcss_list); *addr = seg->start_addr; *end = seg->end; @@ -422,7 +423,7 @@ segment_load (char *name, int do_nonshared, unsigned long *addr, rc = __segment_load (name, do_nonshared, addr, end); else { if (do_nonshared == seg->do_nonshared) { - atomic_inc(&seg->ref_count); + refcount_inc(&seg->ref_count); *addr = seg->start_addr; *end = seg->end; rc = seg->vm_segtype; @@ -468,7 +469,7 @@ segment_modify_shared (char *name, int do_nonshared) rc = 0; goto out_unlock; } - if (atomic_read (&seg->ref_count) != 1) { + if (refcount_read(&seg->ref_count) != 1) { pr_warn("DCSS %s is in use and cannot be reloaded\n", name); rc = -EAGAIN; goto out_unlock; @@ -544,7 +545,7 @@ segment_unload(char *name) pr_err("Unloading unknown DCSS %s failed\n", name); goto out_unlock; } - if (atomic_dec_return(&seg->ref_count) != 0) + if (!refcount_dec_and_test(&seg->ref_count)) goto out_unlock; release_resource(seg->res); kfree(seg->res); |