Commit 18e98e56 authored by Barry Song's avatar Barry Song Committed by Linus Torvalds
Browse files

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: default avatarBarry Song <song.bao.hua@hisilicon.com>
Signed-off-by: default avatarNathan Chancellor <natechancellor@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Acked-by: default avatarRoman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/20200616223131.33828-2-song.bao.hua@hisilicon.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 835832ba

mm/cma.c

+7 −8
Original line number Diff line number Diff line
@@ -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;

mm/cma.h

+3 −1
Original line number Diff line number Diff line
@@ -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];