From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c438c-0000zj-MF for qemu-devel@nongnu.org; Tue, 08 Nov 2016 04:56:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c438Y-0006uS-KJ for qemu-devel@nongnu.org; Tue, 08 Nov 2016 04:56:18 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54994 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c438Y-0006u6-E8 for qemu-devel@nongnu.org; Tue, 08 Nov 2016 04:56:14 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uA89sAnL025629 for ; Tue, 8 Nov 2016 04:56:14 -0500 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0a-001b2d01.pphosted.com with ESMTP id 26kbjy3665-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 08 Nov 2016 04:56:13 -0500 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Nov 2016 09:56:11 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 3D5CD219004D for ; Tue, 8 Nov 2016 09:55:23 +0000 (GMT) Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id uA89u8Rt38863096 for ; Tue, 8 Nov 2016 09:56:08 GMT Received: from d06av02.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id uA89u8GD029329 for ; Tue, 8 Nov 2016 02:56:08 -0700 From: Halil Pasic Date: Tue, 8 Nov 2016 10:56:01 +0100 In-Reply-To: <20161108095603.72301-1-pasic@linux.vnet.ibm.com> References: <20161108095603.72301-1-pasic@linux.vnet.ibm.com> Message-Id: <20161108095603.72301-7-pasic@linux.vnet.ibm.com> Subject: [Qemu-devel] [RFC PATCH v2 6/8] migration/vmstate: split up vmstate_base_addr List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Amit Shah , Juan Quintela , Guenther Hutzl , "Dr. David Alan Gilbert" , Halil Pasic Currently vmstate_base_addr does several things: it pinpoints the field within the struct, possibly allocates memory and possibly does the first pointer dereference. Obviously allocation is needed only for load. Let us split up the functionality in vmstate_base_addr and move the address manipulations (that is everything but the allocation logic) to load and save so it becomes more obvious what is actually going on. Like this all the address calculations (and the handling of the flags controlling these) is in one place and the sequence is more obvious. The newly introduced function vmstate_handle_alloc also fixes the allocation for the unused VMS_VBUFFER| VMS_MULTIPLY scenario and is substantially simpler than the original vmstate_base_addr. In load and save some asserts are added so it's easier to debug situations where we would end up with a null pointer dereference. Signed-off-by: Halil Pasic --- migration/vmstate.c | 41 ++++++++++++++++++----------------------- 1 file changed, 18 insertions(+), 23 deletions(-) diff --git a/migration/vmstate.c b/migration/vmstate.c index a86fb7e..10a7645 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -50,29 +50,15 @@ static int vmstate_size(void *opaque, VMStateField *field) return size; } -static void *vmstate_base_addr(void *opaque, VMStateField *field, bool alloc) -{ - void *base_addr = opaque + field->offset; - - if (field->flags & VMS_POINTER) { - if (alloc && (field->flags & VMS_ALLOC)) { - gsize size = 0; - if (field->flags & VMS_VBUFFER) { - size = vmstate_size(opaque, field); - } else { - int n_elems = vmstate_n_elems(opaque, field); - if (n_elems) { - size = n_elems * field->size; - } - } - if (size) { - *(void **)base_addr = g_malloc(size); - } +static void vmstate_handle_alloc(void *ptr, VMStateField *field, void *opaque) +{ + if (field->flags & VMS_POINTER && field->flags & VMS_ALLOC) { + gsize size = vmstate_size(opaque, field); + size *= vmstate_n_elems(opaque, field); + if (size) { + *(void **)ptr = g_malloc(size); } - base_addr = *(void **)base_addr; } - - return base_addr; } int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, @@ -108,10 +94,15 @@ int vmstate_load_state(QEMUFile *f, const VMStateDescription *vmsd, field->field_exists(opaque, version_id)) || (!field->field_exists && field->version_id <= version_id)) { - void *first_elem = vmstate_base_addr(opaque, field, true); + void *first_elem = opaque + field->offset; int i, n_elems = vmstate_n_elems(opaque, field); int size = vmstate_size(opaque, field); + vmstate_handle_alloc(first_elem, field, opaque); + if (field->flags & VMS_POINTER) { + first_elem = *(void **)first_elem; + assert(first_elem); + } for (i = 0; i < n_elems; i++) { void *curr_elem = first_elem + size * i; @@ -310,12 +301,16 @@ void vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd, while (field->name) { if (!field->field_exists || field->field_exists(opaque, vmsd->version_id)) { - void *first_elem = vmstate_base_addr(opaque, field, false); + void *first_elem = opaque + field->offset; int i, n_elems = vmstate_n_elems(opaque, field); int size = vmstate_size(opaque, field); int64_t old_offset, written_bytes; QJSON *vmdesc_loop = vmdesc; + if (field->flags & VMS_POINTER) { + first_elem = *(void **)first_elem; + assert(first_elem); + } for (i = 0; i < n_elems; i++) { void *curr_elem = first_elem + size * i; -- 2.8.4