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From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: kvm@vger.kernel.org
Cc: frankja@linux.ibm.com, david@redhat.com, thuth@redhat.com,
	pbonzini@redhat.com, cohuck@redhat.com, lvivier@redhat.com,
	nadav.amit@gmail.com, krish.sadhukhan@oracle.com
Subject: [kvm-unit-tests PATCH v2 03/11] lib/vmalloc: add some asserts and improvements
Date: Fri, 15 Jan 2021 13:37:22 +0100	[thread overview]
Message-ID: <20210115123730.381612-4-imbrenda@linux.ibm.com> (raw)
In-Reply-To: <20210115123730.381612-1-imbrenda@linux.ibm.com>

Add some asserts to make sure the state is consistent.

Simplify and improve the readability of vm_free.

If a NULL pointer is freed, no operation is performed.

Fixes: 3f6fee0d4da4 ("lib/vmalloc: vmalloc support for handling allocation metadata")

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 lib/vmalloc.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/lib/vmalloc.c b/lib/vmalloc.c
index 986a34c..6b52790 100644
--- a/lib/vmalloc.c
+++ b/lib/vmalloc.c
@@ -162,13 +162,16 @@ static void *vm_memalign(size_t alignment, size_t size)
 static void vm_free(void *mem)
 {
 	struct metadata *m;
-	uintptr_t ptr, end;
+	uintptr_t ptr, page, i;
 
+	if (!mem)
+		return;
 	/* the pointer is not page-aligned, it was a single-page allocation */
 	if (!IS_ALIGNED((uintptr_t)mem, PAGE_SIZE)) {
 		assert(GET_MAGIC(mem) == VM_MAGIC);
-		ptr = virt_to_pte_phys(page_root, mem) & PAGE_MASK;
-		free_page(phys_to_virt(ptr));
+		page = virt_to_pte_phys(page_root, mem) & PAGE_MASK;
+		assert(page);
+		free_page(phys_to_virt(page));
 		return;
 	}
 
@@ -176,13 +179,14 @@ static void vm_free(void *mem)
 	m = GET_METADATA(mem);
 	assert(m->magic == VM_MAGIC);
 	assert(m->npages > 0);
+	assert(m->npages < BIT_ULL(BITS_PER_LONG - PAGE_SHIFT));
 	/* free all the pages including the metadata page */
-	ptr = (uintptr_t)mem - PAGE_SIZE;
-	end = ptr + m->npages * PAGE_SIZE;
-	for ( ; ptr < end; ptr += PAGE_SIZE)
-		free_page(phys_to_virt(virt_to_pte_phys(page_root, (void *)ptr)));
-	/* free the last one separately to avoid overflow issues */
-	free_page(phys_to_virt(virt_to_pte_phys(page_root, (void *)ptr)));
+	ptr = (uintptr_t)m & PAGE_MASK;
+	for (i = 0 ; i < m->npages + 1; i++, ptr += PAGE_SIZE) {
+		page = virt_to_pte_phys(page_root, (void *)ptr) & PAGE_MASK;
+		assert(page);
+		free_page(phys_to_virt(page));
+	}
 }
 
 static struct alloc_ops vmalloc_ops = {
-- 
2.26.2


  parent reply	other threads:[~2021-01-15 12:43 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-15 12:37 [kvm-unit-tests PATCH v2 00/11] Fix and improve the page allocator Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 01/11] lib/x86: fix page.h to include the generic header Claudio Imbrenda
2021-01-19 15:12   ` Janosch Frank
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 02/11] lib/list.h: add list_add_tail Claudio Imbrenda
2021-01-19 15:18   ` Janosch Frank
2021-01-15 12:37 ` Claudio Imbrenda [this message]
2021-01-19 15:26   ` [kvm-unit-tests PATCH v2 03/11] lib/vmalloc: add some asserts and improvements Janosch Frank
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 04/11] lib/asm: Fix definitions of memory areas Claudio Imbrenda
2021-01-19 15:33   ` Janosch Frank
2021-01-19 17:05     ` Claudio Imbrenda
2021-01-21  1:23   ` David Matlack
2021-01-21  5:32     ` Thomas Huth
2021-01-21  9:28     ` Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 05/11] lib/alloc_page: fix and improve the page allocator Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 06/11] lib/alloc.h: remove align_min from struct alloc_ops Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 07/11] lib/alloc_page: Optimization to skip known empty freelists Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 08/11] lib/alloc_page: rework metadata format Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 09/11] lib/alloc: replace areas with more generic flags Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 10/11] lib/alloc_page: Wire up FLAG_DONTZERO Claudio Imbrenda
2021-01-15 12:37 ` [kvm-unit-tests PATCH v2 11/11] lib/alloc_page: Properly handle requests for fresh blocks Claudio Imbrenda

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