Re: [kvm-unit-tests PATCH v2 4/6] x86: lib/alloc: move heap management to lib

[Laurent Vivier <lvivier@redhat.com>]

On 02/11/2016 21:52, Andrew Jones wrote:
> This will allow other arches to use {alloc,free}_page.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  lib/alloc.c         | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/alloc.h         | 10 ++++++++++
>  lib/x86/vm.c        | 48 ++----------------------------------------------
>  x86/Makefile.common |  1 +
>  4 files changed, 62 insertions(+), 46 deletions(-)
> 
> diff --git a/lib/alloc.c b/lib/alloc.c
> index 1d990a803825..ce1198e2977f 100644
> --- a/lib/alloc.c
> +++ b/lib/alloc.c
> @@ -5,6 +5,7 @@
>   */
>  #include "alloc.h"
>  #include "asm/spinlock.h"
> +#include "asm/page.h"
>  #include "asm/io.h"
>  
>  #define MIN(a, b)		((a) < (b) ? (a) : (b))
> @@ -150,6 +151,54 @@ phys_addr_t phys_zalloc(phys_addr_t size)
>  	return phys_zalloc_aligned(size, phys_alloc_align_min);
>  }
>  
> +static struct spinlock heap_lock;
> +static void *heap_free_head;
> +
> +void heap_init(void *start, size_t size)
> +{
> +	void *p = start;

why do you introduce "p"? It's not obvious for me...

> +
> +	assert(!((unsigned long)start & ~PAGE_MASK));
> +
> +	spin_lock(&heap_lock);
> +
> +	heap_free_head = NULL;
> +
> +	while (size >= PAGE_SIZE) {
> +		*(void **)p = heap_free_head;
> +		heap_free_head = p;
> +		p += PAGE_SIZE;
> +		size -= PAGE_SIZE;
> +	}
> +
> +	spin_unlock(&heap_lock);
> +}
> +
> +void *alloc_page(void)
> +{
> +	void *p;
> +
> +	spin_lock(&heap_lock);
> +
> +	if (!heap_free_head)
> +		return NULL;

missing unlock propagated from PATCH 1

Laurent