[merged mm-stable] vmalloc-use-atomic_long_add_return_relaxed.patch removed from -mm tree

[merged mm-stable] vmalloc-use-atomic_long_add_return_relaxed.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: vmalloc: use atomic_long_add_return_relaxed()
has been removed from the -mm tree.  Its filename was
     vmalloc-use-atomic_long_add_return_relaxed.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Subject: vmalloc: use atomic_long_add_return_relaxed()
Date: Tue, 15 Apr 2025 13:26:46 +0200

Switch from the atomic_long_add_return() to its relaxed version.

We do not need a full memory barrier or any memory ordering during
increasing the "vmap_lazy_nr" variable.  What we only need is to do it
atomically.  This is what atomic_long_add_return_relaxed() guarantees.

AARCH64:

<snip>
Default:
    40ec:       d34cfe94        lsr     x20, x20, #12
    40f0:       14000044        b       4200 <free_vmap_area_noflush+0x19c>
    40f4:       94000000        bl      0 <__sanitizer_cov_trace_pc>
    40f8:       90000000        adrp    x0, 0 <__traceiter_alloc_vmap_area>
    40fc:       91000000        add     x0, x0, #0x0
    4100:       f8f40016        ldaddal x20, x22, [x0]
    4104:       8b160296        add     x22, x20, x22

Relaxed:
    40ec:       d34cfe94        lsr     x20, x20, #12
    40f0:       14000044        b       4200 <free_vmap_area_noflush+0x19c>
    40f4:       94000000        bl      0 <__sanitizer_cov_trace_pc>
    40f8:       90000000        adrp    x0, 0 <__traceiter_alloc_vmap_area>
    40fc:       91000000        add     x0, x0, #0x0
    4100:       f8340016        ldadd   x20, x22, [x0]
    4104:       8b160296        add     x22, x20, x22
<snip>

Link: https://lkml.kernel.org/r/20250415112646.113091-1-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Christop Hellwig <hch@infradead.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/vmalloc.c~vmalloc-use-atomic_long_add_return_relaxed
+++ a/mm/vmalloc.c
@@ -2370,7 +2370,7 @@ static void free_vmap_area_noflush(struc
 	if (WARN_ON_ONCE(!list_empty(&va->list)))
 		return;
 
-	nr_lazy = atomic_long_add_return(va_size(va) >> PAGE_SHIFT,
+	nr_lazy = atomic_long_add_return_relaxed(va_size(va) >> PAGE_SHIFT,
 					 &vmap_lazy_nr);
 
 	/*
_

Patches currently in -mm which might be from urezki@gmail.com are

maintainers-add-myself-as-vmalloc-co-maintainer.patch