linux-kernel - Re: [PATCH] mm: refactor __vunmap() to avoid duplicated call to find_vm

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Date:   Wed, 15 May 2019 10:35:26 -0700
From:   Ira Weiny <ira.weiny@...el.com>
To:     Roman Gushchin <guro@...com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, kernel-team@...com,
        Johannes Weiner <hannes@...xchg.org>,
        Matthew Wilcox <willy@...radead.org>,
        Vlastimil Babka <vbabka@...e.cz>
Subject: Re: [PATCH] mm: refactor __vunmap() to avoid duplicated call to
 find_vm_area()

>  
> -/* Handle removing and resetting vm mappings related to the vm_struct. */
> -static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
> +/* Handle removing and resetting vm mappings related to the va->vm vm_struct. */
> +static void vm_remove_mappings(struct vmap_area *va, int deallocate_pages)

Does this apply to 5.1?  I'm confused because I can't find vm_remove_mappings()
in 5.1.

Ira

>  {
> +	struct vm_struct *area = va->vm;
>  	unsigned long addr = (unsigned long)area->addr;
>  	unsigned long start = ULONG_MAX, end = 0;
>  	int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
> @@ -2138,7 +2143,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
>  		set_memory_rw(addr, area->nr_pages);
>  	}
>  
> -	remove_vm_area(area->addr);
> +	__remove_vm_area(va);
>  
>  	/* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */
>  	if (!flush_reset)
> @@ -2178,6 +2183,7 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
>  static void __vunmap(const void *addr, int deallocate_pages)
>  {
>  	struct vm_struct *area;
> +	struct vmap_area *va;
>  
>  	if (!addr)
>  		return;
> @@ -2186,17 +2192,18 @@ static void __vunmap(const void *addr, int deallocate_pages)
>  			addr))
>  		return;
>  
> -	area = find_vm_area(addr);
> -	if (unlikely(!area)) {
> +	va = find_vmap_area((unsigned long)addr);
> +	if (unlikely(!va || !(va->flags & VM_VM_AREA))) {
>  		WARN(1, KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
>  				addr);
>  		return;
>  	}
>  
> +	area = va->vm;
>  	debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
>  	debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
>  
> -	vm_remove_mappings(area, deallocate_pages);
> +	vm_remove_mappings(va, deallocate_pages);
>  
>  	if (deallocate_pages) {
>  		int i;
> @@ -2212,7 +2219,6 @@ static void __vunmap(const void *addr, int deallocate_pages)
>  	}
>  
>  	kfree(area);
> -	return;
>  }
>  
>  static inline void __vfree_deferred(const void *addr)
> -- 
> 2.20.1
>