Subject: Re: [PATCH] Allow sharing xvmalloc for zram and zcache

From: Randy Dunlap <[email-masked]>
Date: Thu, 10 Feb 2011 13:08:27 -0800

On 02/10/11 13:00, Nitin Gupta wrote:
> Both zram and zcache use xvmalloc allocator. If xvmalloc
> is compiled separately for both of them, we will get linker
> error if they are both selected as "built-in". We can also
> get linker error regarding missing xvmalloc symbols if zram
> is not built.
> 
> So, we now compile xvmalloc separately and export its symbols
> which are then used by both of zram and zcache.
> 
> Signed-off-by: Nitin Gupta <[email-masked]>

Acked-by: Randy Dunlap <[email-masked]>

but what does this patch apply to?  It does not apply cleanly to
linux-next of 20110210.

> ---
>  drivers/staging/Makefile        |    1 +
>  drivers/staging/zcache/Makefile |    4 +++-
>  drivers/staging/zram/Kconfig    |    5 +++++
>  drivers/staging/zram/Makefile   |    3 ++-
>  drivers/staging/zram/xvmalloc.c |    8 ++++++++
>  5 files changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
> index 9edbfec..f7ab035 100644
> --- a/drivers/staging/Makefile
> +++ b/drivers/staging/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_DX_SEP)            += sep/
>  obj-$(CONFIG_IIO)		+= iio/
>  obj-$(CONFIG_CS5535_GPIO)	+= cs5535_gpio/
>  obj-$(CONFIG_ZRAM)		+= zram/
> +obj-$(CONFIG_XVMALLOC)		+= zram/
>  obj-$(CONFIG_ZCACHE)		+= zcache/
>  obj-$(CONFIG_WLAGS49_H2)	+= wlags49_h2/
>  obj-$(CONFIG_WLAGS49_H25)	+= wlags49_h25/
> diff --git a/drivers/staging/zcache/Makefile b/drivers/staging/zcache/Makefile
> index 7f64de4..f5ec64f 100644
> --- a/drivers/staging/zcache/Makefile
> +++ b/drivers/staging/zcache/Makefile
> @@ -1 +1,3 @@
> -obj-$(CONFIG_ZCACHE)	+=	zcache.o tmem.o
> +zcache-y	:=	tmem.o
> +
> +obj-$(CONFIG_ZCACHE)	+=	zcache.o
> diff --git a/drivers/staging/zram/Kconfig b/drivers/staging/zram/Kconfig
> index da079f8..1516ea4 100644
> --- a/drivers/staging/zram/Kconfig
> +++ b/drivers/staging/zram/Kconfig
> @@ -1,6 +1,11 @@
> +config XVMALLOC
> +	bool
> +	default n
> +
>  config ZRAM
>  	tristate "Compressed RAM block device support"
>  	depends on BLOCK
> +	select XVMALLOC
>  	select LZO_COMPRESS
>  	select LZO_DECOMPRESS
>  	default n
> diff --git a/drivers/staging/zram/Makefile b/drivers/staging/zram/Makefile
> index b1709c5..2a6d321 100644
> --- a/drivers/staging/zram/Makefile
> +++ b/drivers/staging/zram/Makefile
> @@ -1,3 +1,4 @@
> -zram-y	:=	zram_drv.o zram_sysfs.o xvmalloc.o
> +zram-y	:=	zram_drv.o zram_sysfs.o
>  
>  obj-$(CONFIG_ZRAM)	+=	zram.o
> +obj-$(CONFIG_XVMALLOC)	+=	xvmalloc.o
> \ No newline at end of file
> diff --git a/drivers/staging/zram/xvmalloc.c b/drivers/staging/zram/xvmalloc.c
> index b644067..aa6fcd8 100644
> --- a/drivers/staging/zram/xvmalloc.c
> +++ b/drivers/staging/zram/xvmalloc.c
> @@ -10,6 +10,8 @@
>   * Released under the terms of GNU General Public License Version 2.0
>   */
>  
> +#include <linux/module.h>
> +#include <linux/kernel.h>
>  #include <linux/bitops.h>
>  #include <linux/errno.h>
>  #include <linux/highmem.h>
> @@ -320,11 +322,13 @@ struct xv_pool *xv_create_pool(void)
>  
>  	return pool;
>  }
> +EXPORT_SYMBOL_GPL(xv_create_pool);
>  
>  void xv_destroy_pool(struct xv_pool *pool)
>  {
>  	kfree(pool);
>  }
> +EXPORT_SYMBOL_GPL(xv_destroy_pool);
>  
>  /**
>   * xv_malloc - Allocate block of given size from pool.
> @@ -413,6 +417,7 @@ int xv_malloc(struct xv_pool *pool, u32 size, struct page **page,
>  
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(xv_malloc);
>  
>  /*
>   * Free block identified with <page, offset>
> @@ -489,6 +494,7 @@ void xv_free(struct xv_pool *pool, struct page *page, u32 offset)
>  	put_ptr_atomic(page_start, KM_USER0);
>  	spin_unlock(&pool->lock);
>  }
> +EXPORT_SYMBOL_GPL(xv_free);
>  
>  u32 xv_get_object_size(void *obj)
>  {
> @@ -497,6 +503,7 @@ u32 xv_get_object_size(void *obj)
>  	blk = (struct block_header *)((char *)(obj) - XV_ALIGN);
>  	return blk->size;
>  }
> +EXPORT_SYMBOL_GPL(xv_get_object_size);
>  
>  /*
>   * Returns total memory used by allocator (userdata + metadata)
> @@ -505,3 +512,4 @@ u64 xv_get_total_size_bytes(struct xv_pool *pool)
>  {
>  	return pool->total_pages << PAGE_SHIFT;
>  }
> +EXPORT_SYMBOL_GPL(xv_get_total_size_bytes);

-- 
~Randy
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