The "memramp() shrinking" scenario no longer applies, so let's remove
that now-unnecessary handling.

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org> # x86 bits
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
 1 file changed, 6 insertions(+), 38 deletions(-)

diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
index 645613d59942a..9d03f0dbc4715 100644
--- a/arch/x86/mm/pat/memtype_interval.c
+++ b/arch/x86/mm/pat/memtype_interval.c
@@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
 
 static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
 
-enum {
-	MEMTYPE_EXACT_MATCH	= 0,
-	MEMTYPE_END_MATCH	= 1
-};
-
-static struct memtype *memtype_match(u64 start, u64 end, int match_type)
+static struct memtype *memtype_match(u64 start, u64 end)
 {
 	struct memtype *entry_match;
 
 	entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
 
 	while (entry_match != NULL && entry_match->start < end) {
-		if ((match_type == MEMTYPE_EXACT_MATCH) &&
-		    (entry_match->start == start) && (entry_match->end == end))
-			return entry_match;
-
-		if ((match_type == MEMTYPE_END_MATCH) &&
-		    (entry_match->start < start) && (entry_match->end == end))
+		if (entry_match->start == start && entry_match->end == end)
 			return entry_match;
-
 		entry_match = interval_iter_next(entry_match, start, end-1);
 	}
 
@@ -132,32 +121,11 @@ struct memtype *memtype_erase(u64 start, u64 end)
 {
 	struct memtype *entry_old;
 
-	/*
-	 * Since the memtype_rbroot tree allows overlapping ranges,
-	 * memtype_erase() checks with EXACT_MATCH first, i.e. free
-	 * a whole node for the munmap case.  If no such entry is found,
-	 * it then checks with END_MATCH, i.e. shrink the size of a node
-	 * from the end for the mremap case.
-	 */
-	entry_old = memtype_match(start, end, MEMTYPE_EXACT_MATCH);
-	if (!entry_old) {
-		entry_old = memtype_match(start, end, MEMTYPE_END_MATCH);
-		if (!entry_old)
-			return ERR_PTR(-EINVAL);
-	}
-
-	if (entry_old->start == start) {
-		/* munmap: erase this node */
-		interval_remove(entry_old, &memtype_rbroot);
-	} else {
-		/* mremap: update the end value of this node */
-		interval_remove(entry_old, &memtype_rbroot);
-		entry_old->end = start;
-		interval_insert(entry_old, &memtype_rbroot);
-
-		return NULL;
-	}
+	entry_old = memtype_match(start, end);
+	if (!entry_old)
+		return ERR_PTR(-EINVAL);
 
+	interval_remove(entry_old, &memtype_rbroot);
 	return entry_old;
 }
 
-- 
2.49.0

* David Hildenbrand <david@redhat.com> [250512 08:34]:
> The "memramp() shrinking" scenario no longer applies, so let's remove
> that now-unnecessary handling.
> 
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> Acked-by: Ingo Molnar <mingo@kernel.org> # x86 bits
> Signed-off-by: David Hildenbrand <david@redhat.com>

small comment, but this looks good.

Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>

> ---
>  arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
>  1 file changed, 6 insertions(+), 38 deletions(-)
> 
> diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
> index 645613d59942a..9d03f0dbc4715 100644
> --- a/arch/x86/mm/pat/memtype_interval.c
> +++ b/arch/x86/mm/pat/memtype_interval.c
> @@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
>  
>  static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
>  
> -enum {
> -	MEMTYPE_EXACT_MATCH	= 0,
> -	MEMTYPE_END_MATCH	= 1
> -};
> -
> -static struct memtype *memtype_match(u64 start, u64 end, int match_type)
> +static struct memtype *memtype_match(u64 start, u64 end)
>  {
>  	struct memtype *entry_match;
>  
>  	entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
>  
>  	while (entry_match != NULL && entry_match->start < end) {

I think this could use interval_tree_for_each_span() instead.

> -		if ((match_type == MEMTYPE_EXACT_MATCH) &&
> -		    (entry_match->start == start) && (entry_match->end == end))
> -			return entry_match;
> -
> -		if ((match_type == MEMTYPE_END_MATCH) &&
> -		    (entry_match->start < start) && (entry_match->end == end))
> +		if (entry_match->start == start && entry_match->end == end)
>  			return entry_match;
> -
>  		entry_match = interval_iter_next(entry_match, start, end-1);
>  	}
>  
> @@ -132,32 +121,11 @@ struct memtype *memtype_erase(u64 start, u64 end)
>  {
>  	struct memtype *entry_old;
>  
> -	/*
> -	 * Since the memtype_rbroot tree allows overlapping ranges,
> -	 * memtype_erase() checks with EXACT_MATCH first, i.e. free
> -	 * a whole node for the munmap case.  If no such entry is found,
> -	 * it then checks with END_MATCH, i.e. shrink the size of a node
> -	 * from the end for the mremap case.
> -	 */
> -	entry_old = memtype_match(start, end, MEMTYPE_EXACT_MATCH);
> -	if (!entry_old) {
> -		entry_old = memtype_match(start, end, MEMTYPE_END_MATCH);
> -		if (!entry_old)
> -			return ERR_PTR(-EINVAL);
> -	}
> -
> -	if (entry_old->start == start) {
> -		/* munmap: erase this node */
> -		interval_remove(entry_old, &memtype_rbroot);
> -	} else {
> -		/* mremap: update the end value of this node */
> -		interval_remove(entry_old, &memtype_rbroot);
> -		entry_old->end = start;
> -		interval_insert(entry_old, &memtype_rbroot);
> -
> -		return NULL;
> -	}
> +	entry_old = memtype_match(start, end);
> +	if (!entry_old)
> +		return ERR_PTR(-EINVAL);
>  
> +	interval_remove(entry_old, &memtype_rbroot);
>  	return entry_old;
>  }
>  
> -- 
> 2.49.0
>

On 13.05.25 19:48, Liam R. Howlett wrote:
> * David Hildenbrand <david@redhat.com> [250512 08:34]:
>> The "memramp() shrinking" scenario no longer applies, so let's remove
>> that now-unnecessary handling.
>>
>> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>> Acked-by: Ingo Molnar <mingo@kernel.org> # x86 bits
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> small comment, but this looks good.
> 
> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>

Thanks!

> 
>> ---
>>   arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
>>   1 file changed, 6 insertions(+), 38 deletions(-)
>>
>> diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
>> index 645613d59942a..9d03f0dbc4715 100644
>> --- a/arch/x86/mm/pat/memtype_interval.c
>> +++ b/arch/x86/mm/pat/memtype_interval.c
>> @@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
>>   
>>   static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
>>   
>> -enum {
>> -	MEMTYPE_EXACT_MATCH	= 0,
>> -	MEMTYPE_END_MATCH	= 1
>> -};
>> -
>> -static struct memtype *memtype_match(u64 start, u64 end, int match_type)
>> +static struct memtype *memtype_match(u64 start, u64 end)
>>   {
>>   	struct memtype *entry_match;
>>   
>>   	entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
>>   
>>   	while (entry_match != NULL && entry_match->start < end) {
> 
> I think this could use interval_tree_for_each_span() instead.

Fancy, let me look at this. Probably I'll send another patch on top of 
this series to do that conversion. (as you found, patch #9 moves that code)

-- 
Cheers,

David / dhildenb

On 14.05.25 19:53, David Hildenbrand wrote:
> On 13.05.25 19:48, Liam R. Howlett wrote:
>> * David Hildenbrand <david@redhat.com> [250512 08:34]:
>>> The "memramp() shrinking" scenario no longer applies, so let's remove
>>> that now-unnecessary handling.
>>>
>>> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>>> Acked-by: Ingo Molnar <mingo@kernel.org> # x86 bits
>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>
>> small comment, but this looks good.
>>
>> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
> 
> Thanks!
> 
>>
>>> ---
>>>    arch/x86/mm/pat/memtype_interval.c | 44 ++++--------------------------
>>>    1 file changed, 6 insertions(+), 38 deletions(-)
>>>
>>> diff --git a/arch/x86/mm/pat/memtype_interval.c b/arch/x86/mm/pat/memtype_interval.c
>>> index 645613d59942a..9d03f0dbc4715 100644
>>> --- a/arch/x86/mm/pat/memtype_interval.c
>>> +++ b/arch/x86/mm/pat/memtype_interval.c
>>> @@ -49,26 +49,15 @@ INTERVAL_TREE_DEFINE(struct memtype, rb, u64, subtree_max_end,
>>>    
>>>    static struct rb_root_cached memtype_rbroot = RB_ROOT_CACHED;
>>>    
>>> -enum {
>>> -	MEMTYPE_EXACT_MATCH	= 0,
>>> -	MEMTYPE_END_MATCH	= 1
>>> -};
>>> -
>>> -static struct memtype *memtype_match(u64 start, u64 end, int match_type)
>>> +static struct memtype *memtype_match(u64 start, u64 end)
>>>    {
>>>    	struct memtype *entry_match;
>>>    
>>>    	entry_match = interval_iter_first(&memtype_rbroot, start, end-1);
>>>    
>>>    	while (entry_match != NULL && entry_match->start < end) {
>>
>> I think this could use interval_tree_for_each_span() instead.
> 
> Fancy, let me look at this. Probably I'll send another patch on top of
> this series to do that conversion. (as you found, patch #9 moves that code)

Hmmm, I think interval_tree_for_each_span() does not apply here.

Unless I am missing something important, interval_tree_for_each_span() 
does not work in combination with INTERVAL_TREE_DEFINE where we want to 
use a custom type as tree nodes (-> struct memtype).

interval_tree_for_each_span() only works with the basic "struct 
interval_tree_node" implementation ... which is probably also why there 
are only a handful (3) of interval_tree_for_each_span() users, all in 
iommufd context?

But staring at interval_tree.h vs. interval_tree_generic.h, I am a bit 
confused ...

-- 
Cheers,

David / dhildenb