Re: [PATCH RESEND v8 05/16] module: make module_memory_{alloc,free} more self-contained

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On Sun,  5 May 2024 19:06:17 +0300
Mike Rapoport <rppt@xxxxxxxxxx> wrote:

> From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
> 
> Move the logic related to the memory allocation and freeing into
> module_memory_alloc() and module_memory_free().
> 

Looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

Thanks,

> Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
> ---
>  kernel/module/main.c | 64 +++++++++++++++++++++++++++-----------------
>  1 file changed, 39 insertions(+), 25 deletions(-)
> 
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index e1e8a7a9d6c1..5b82b069e0d3 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -1203,15 +1203,44 @@ static bool mod_mem_use_vmalloc(enum mod_mem_type type)
>  		mod_mem_type_is_core_data(type);
>  }
>  
> -static void *module_memory_alloc(unsigned int size, enum mod_mem_type type)
> +static int module_memory_alloc(struct module *mod, enum mod_mem_type type)
>  {
> +	unsigned int size = PAGE_ALIGN(mod->mem[type].size);
> +	void *ptr;
> +
> +	mod->mem[type].size = size;
> +
>  	if (mod_mem_use_vmalloc(type))
> -		return vzalloc(size);
> -	return module_alloc(size);
> +		ptr = vmalloc(size);
> +	else
> +		ptr = module_alloc(size);
> +
> +	if (!ptr)
> +		return -ENOMEM;
> +
> +	/*
> +	 * The pointer to these blocks of memory are stored on the module
> +	 * structure and we keep that around so long as the module is
> +	 * around. We only free that memory when we unload the module.
> +	 * Just mark them as not being a leak then. The .init* ELF
> +	 * sections *do* get freed after boot so we *could* treat them
> +	 * slightly differently with kmemleak_ignore() and only grey
> +	 * them out as they work as typical memory allocations which
> +	 * *do* eventually get freed, but let's just keep things simple
> +	 * and avoid *any* false positives.
> +	 */
> +	kmemleak_not_leak(ptr);
> +
> +	memset(ptr, 0, size);
> +	mod->mem[type].base = ptr;
> +
> +	return 0;
>  }
>  
> -static void module_memory_free(void *ptr, enum mod_mem_type type)
> +static void module_memory_free(struct module *mod, enum mod_mem_type type)
>  {
> +	void *ptr = mod->mem[type].base;
> +
>  	if (mod_mem_use_vmalloc(type))
>  		vfree(ptr);
>  	else
> @@ -1229,12 +1258,12 @@ static void free_mod_mem(struct module *mod)
>  		/* Free lock-classes; relies on the preceding sync_rcu(). */
>  		lockdep_free_key_range(mod_mem->base, mod_mem->size);
>  		if (mod_mem->size)
> -			module_memory_free(mod_mem->base, type);
> +			module_memory_free(mod, type);
>  	}
>  
>  	/* MOD_DATA hosts mod, so free it at last */
>  	lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
> -	module_memory_free(mod->mem[MOD_DATA].base, MOD_DATA);
> +	module_memory_free(mod, MOD_DATA);
>  }
>  
>  /* Free a module, remove from lists, etc. */
> @@ -2225,7 +2254,6 @@ static int find_module_sections(struct module *mod, struct load_info *info)
>  static int move_module(struct module *mod, struct load_info *info)
>  {
>  	int i;
> -	void *ptr;
>  	enum mod_mem_type t = 0;
>  	int ret = -ENOMEM;
>  
> @@ -2234,26 +2262,12 @@ static int move_module(struct module *mod, struct load_info *info)
>  			mod->mem[type].base = NULL;
>  			continue;
>  		}
> -		mod->mem[type].size = PAGE_ALIGN(mod->mem[type].size);
> -		ptr = module_memory_alloc(mod->mem[type].size, type);
> -		/*
> -                 * The pointer to these blocks of memory are stored on the module
> -                 * structure and we keep that around so long as the module is
> -                 * around. We only free that memory when we unload the module.
> -                 * Just mark them as not being a leak then. The .init* ELF
> -                 * sections *do* get freed after boot so we *could* treat them
> -                 * slightly differently with kmemleak_ignore() and only grey
> -                 * them out as they work as typical memory allocations which
> -                 * *do* eventually get freed, but let's just keep things simple
> -                 * and avoid *any* false positives.
> -		 */
> -		kmemleak_not_leak(ptr);
> -		if (!ptr) {
> +
> +		ret = module_memory_alloc(mod, type);
> +		if (ret) {
>  			t = type;
>  			goto out_enomem;
>  		}
> -		memset(ptr, 0, mod->mem[type].size);
> -		mod->mem[type].base = ptr;
>  	}
>  
>  	/* Transfer each section which specifies SHF_ALLOC */
> @@ -2296,7 +2310,7 @@ static int move_module(struct module *mod, struct load_info *info)
>  	return 0;
>  out_enomem:
>  	for (t--; t >= 0; t--)
> -		module_memory_free(mod->mem[t].base, t);
> +		module_memory_free(mod, t);
>  	return ret;
>  }
>  
> -- 
> 2.43.0
> 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>