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mm: cma: fix the name of CMA areas

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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>
This commit is contained in:
Barry Song 2020-08-11 18:31:57 -07:00 committed by Linus Torvalds
parent 835832ba01
commit 18e98e56f4
2 changed files with 10 additions and 9 deletions
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15
mm/cma.c
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@ -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;

4
mm/cma.h
View File

@ -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];