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authorBarry Song <song.bao.hua@hisilicon.com>2020-08-11 18:31:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-12 10:57:57 -0700
commit18e98e56f4407b8c766b6f6d9f2850fd2a081e4d (patch)
tree9ddb1fef5f305dcca449ed76a8c2389d00353f9f
parent835832ba01bb444c7e45139e4b807527c119dafc (diff)
mm: cma: fix the name of CMA areas
Patch series "mm: fix the names of general cma and hugetlb cma", v2. The current code of CMA can only work when users pass a const string as name parameter. we need to fix the way to handle names in CMA. On the other hand, to avoid name conflicts after enabling CMA_DEBUGFS, each hugetlb should get a different CMA name. This patch (of 2): If users give a name saved in stack, the current code will generate magic pointer. if users don't give a name(NULL), kasprintf() will always return NULL as we are at the early stage. that means cma_init_reserved_mem() will return -ENOMEM if users set name parameter as NULL. [natechancellor@gmail.com: return cma->name directly in cma_get_name] Link: https://github.com/ClangBuiltLinux/linux/issues/1063 Link: http://lkml.kernel.org/r/20200623015840.621964-1-natechancellor@gmail.com Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Roman Gushchin <guro@fb.com> Link: http://lkml.kernel.org/r/20200616223131.33828-2-song.bao.hua@hisilicon.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/cma.c15
-rw-r--r--mm/cma.h4
2 files changed, 10 insertions, 9 deletions
diff --git a/mm/cma.c b/mm/cma.c
index 3a18f8d8ea5e..aa2df0bd49c3 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -52,7 +52,7 @@ unsigned long cma_get_size(const struct cma *cma)
const char *cma_get_name(const struct cma *cma)
{
- return cma->name ? cma->name : "(undefined)";
+ return cma->name;
}
static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
@@ -202,13 +202,12 @@ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
* subsystems (like slab allocator) are available.
*/
cma = &cma_areas[cma_area_count];
- if (name) {
- cma->name = name;
- } else {
- cma->name = kasprintf(GFP_KERNEL, "cma%d\n", cma_area_count);
- if (!cma->name)
- return -ENOMEM;
- }
+
+ if (name)
+ snprintf(cma->name, CMA_MAX_NAME, name);
+ else
+ snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);
+
cma->base_pfn = PFN_DOWN(base);
cma->count = size >> PAGE_SHIFT;
cma->order_per_bit = order_per_bit;
diff --git a/mm/cma.h b/mm/cma.h
index 6698fa63279b..20f6e24bc477 100644
--- a/mm/cma.h
+++ b/mm/cma.h
@@ -4,6 +4,8 @@
#include <linux/debugfs.h>
+#define CMA_MAX_NAME 64
+
struct cma {
unsigned long base_pfn;
unsigned long count;
@@ -15,7 +17,7 @@ struct cma {
spinlock_t mem_head_lock;
struct debugfs_u32_array dfs_bitmap;
#endif
- const char *name;
+ char name[CMA_MAX_NAME];
};
extern struct cma cma_areas[MAX_CMA_AREAS];