linux-kernel - [PATCH 2/2] mm: vmalloc: Refactor vmalloc_dump

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Message-Id: <20240124180920.50725-2-urezki@gmail.com>
Date: Wed, 24 Jan 2024 19:09:20 +0100
From: "Uladzislau Rezki (Sony)" <urezki@...il.com>
To: linux-mm@...ck.org,
	Andrew Morton <akpm@...ux-foundation.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
	Baoquan He <bhe@...hat.com>,
	Lorenzo Stoakes <lstoakes@...il.com>,
	Christoph Hellwig <hch@...radead.org>,
	Matthew Wilcox <willy@...radead.org>,
	Dave Chinner <david@...morbit.com>,
	Uladzislau Rezki <urezki@...il.com>,
	Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>
Subject: [PATCH 2/2] mm: vmalloc: Refactor vmalloc_dump_obj() function

This patch tends to simplify the function in question,
by removing an extra stack "objp" variable, returning
back to an early exit approach if spin_trylock() fails
or VA was not found.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
 mm/vmalloc.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index b8be601b056d..449f45b0e474 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4696,34 +4696,35 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 #ifdef CONFIG_PRINTK
 bool vmalloc_dump_obj(void *object)
 {
-	void *objp = (void *)PAGE_ALIGN((unsigned long)object);
 	const void *caller;
+	struct vm_struct *vm;
 	struct vmap_area *va;
 	struct vmap_node *vn;
 	unsigned long addr;
 	unsigned int nr_pages;
-	bool success = false;
-
-	vn = addr_to_node((unsigned long)objp);
 
-	if (spin_trylock(&vn->busy.lock)) {
-		va = __find_vmap_area((unsigned long)objp, &vn->busy.root);
+	addr = PAGE_ALIGN((unsigned long) object);
+	vn = addr_to_node(addr);
 
-		if (va && va->vm) {
-			addr = (unsigned long)va->vm->addr;
-			caller = va->vm->caller;
-			nr_pages = va->vm->nr_pages;
-			success = true;
-		}
+	if (!spin_trylock(&vn->busy.lock))
+		return false;
 
+	va = __find_vmap_area(addr, &vn->busy.root);
+	if (!va || !va->vm) {
 		spin_unlock(&vn->busy.lock);
+		return false;
 	}
 
-	if (success)
-		pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n",
-			nr_pages, addr, caller);
+	vm = va->vm;
+	addr = (unsigned long) vm->addr;
+	caller = vm->caller;
+	nr_pages = vm->nr_pages;
+	spin_unlock(&vn->busy.lock);
 
-	return success;
+	pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n",
+		nr_pages, addr, caller);
+
+	return true;
 }
 #endif
 
-- 
2.39.2