Alignment padding inserts a pseudo block header in front of the allocation,
sets its size field to the pad size and then ORs in 1, which is equivalent
to marking it as a free block, so that xfree() can distinguish it from a
real block header.
This patch simply replaces the magic '1' with the defined 'FREE_BLOCK' to
make it more obvious what's going on. Also, whilst in the neighbourhood,
it removes a stray space after a cast.
Signed-off-by: Paul Durrant <paul.durr...@citrix.com>
---
Cc: Andrew Cooper <andrew.coop...@citrix.com>
Cc: George Dunlap <george.dun...@eu.citrix.com>
Cc: Ian Jackson <ian.jack...@eu.citrix.com>
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Julien Grall <julien.gr...@arm.com>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Tim Deegan <t...@xen.org>
Cc: Wei Liu <w...@xen.org>
---
xen/common/xmalloc_tlsf.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/xen/common/xmalloc_tlsf.c b/xen/common/xmalloc_tlsf.c
index 2076953ac4..6d889b7bdc 100644
--- a/xen/common/xmalloc_tlsf.c
+++ b/xen/common/xmalloc_tlsf.c
@@ -595,7 +595,7 @@ void *_xmalloc(unsigned long size, unsigned long align)
char *q = (char *)p + pad;
struct bhdr *b = (struct bhdr *)(q - BHDR_OVERHEAD);
ASSERT(q > (char *)p);
- b->size = pad | 1;
+ b->size = pad | FREE_BLOCK;
p = q;
}
@@ -638,12 +638,12 @@ void xfree(void *p)
}
/* Strip alignment padding. */
- b = (struct bhdr *)((char *) p - BHDR_OVERHEAD);
- if ( b->size & 1 )
+ b = (struct bhdr *)((char *)p - BHDR_OVERHEAD);
+ if ( b->size & FREE_BLOCK )
{
p = (char *)p - (b->size & ~1u);
b = (struct bhdr *)((char *)p - BHDR_OVERHEAD);
- ASSERT(!(b->size & 1));
+ ASSERT(!(b->size & FREE_BLOCK));
}
xmem_pool_free(p, xenpool);
--
2.20.1.2.gb21ebb671
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