Lets not put statements with side-effects inside BUG_ON()

BUG_ON() is a macro very very similar to assert(), and it's a really bad idea in general to put statements with side-effects inside such a construct (for example the BUG_ON() could be compiled away for non-debug builds).

The patch below fixes this for the drivers/xen tree.

Quoted 5 lines · Arjan van de Ven

BUG_ON() is a macro very very similar to assert(), and it's a really bad idea in general to put statements with side-effects inside such a construct (for example the BUG_ON() could be compiled away for non-debug builds).

The patch below fixes this for the drivers/xen tree.

I'd like to see this applied, to both Xen and the vanilla kernel; however, it should be noted that no version of Linux or Xen compiles BUG_ON() away without evaluating its arguments.

Hi,

BUG_ON() is a macro very very similar to assert(), and it's a really bad idea in general to put statements with side-effects inside such a construct
(for example the BUG_ON() could be compiled away for non-debug builds).

The patch below fixes this for the drivers/xen tree.

I chose the general construct to store the respective return values in a local var instead of an if (...) BUG(); because it looks like most of these
BUG_ON()'s need to be replaced by real error handling when going towards production releases anyway, and then the local variable is going to be needed anyway. (and besides the if construct tends to get unreable due to the unlikely() etc).

Please apply.

Greetings,
Arjan van de Ven

diff -purN linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c
--- linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c 2005-10-26 17:13:
26.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/balloon/balloon.c 2005-10-27 11:26:
28.000000000 +0200

(quoted diff) +0 -0

@@ -191,12 +191,13 @@ static int increase_reservation(unsigned

rc = HYPERVISOR_memory_op( XENMEM_increase_reservation, &reservation);
if (rc < nr_pages) {
+ int ret;
/* We hit the Xen hard limit: reprobe. */ reservation.extent_start = mfn_list; reservation.nr_extents = rc;
- BUG_ON(HYPERVISOR_memory_op(
- XENMEM_decrease_reservation,
- &reservation) != rc);
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+ &reservation);
+ BUG_ON(ret != rc);
hard_limit = current_pages + rc - driver_pages; goto out;
}

drivers/xen/balloon/balloon.c +13 -7

@@ -213,11 +214,14 @@ static int increase_reservation(unsigned
 xen_machphys_update(mfn_list[i], pfn);
 
 /* Link back into the page tables if not highmem. */
- if (pfn < max_low_pfn)
- BUG_ON(HYPERVISOR_update_va_mapping(
+ if (pfn < max_low_pfn) {
+ int ret;
+ ret = HYPERVISOR_update_va_mapping(
 (unsigned long)__va(pfn << PAGE_SHIFT),
 pfn_pte_ma(mfn_list[i], PAGE_KERNEL),
- 0));
+ 0);
+ BUG_ON(ret);
+ }
 
 /* Relinquish the page back to the allocator. */
 ClearPageReserved(page);

@@ -242,6 +246,7 @@ static int decrease_reservation(unsigned
 struct page *page;
 void *v;
 int need_sleep = 0;
+ int ret;
 struct xen_memory_reservation reservation = {
 .address_bits = 0,
 .extent_order = 0,

@@ -268,8 +273,9 @@ static int decrease_reservation(unsigned
 if (!PageHighMem(page)) {
 v = phys_to_virt(pfn << PAGE_SHIFT);
 scrub_pages(v, 1);
- BUG_ON(HYPERVISOR_update_va_mapping(
- (unsigned long)v, __pte_ma(0), 0));
+ ret = HYPERVISOR_update_va_mapping(
+ (unsigned long)v, __pte_ma(0), 0);
+ BUG_ON(ret);
 }
 #ifdef CONFIG_XEN_SCRUB_PAGES
 else {

@@ -295,8 +301,8 @@ static int decrease_reservation(unsigned
 
 reservation.extent_start = mfn_list;
 reservation.nr_extents = nr_pages;
- BUG_ON(HYPERVISOR_memory_op(
- XENMEM_decrease_reservation, &reservation) != nr_pages);
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
+ BUG_ON(ret != nr_pages);
 
 current_pages -= nr_pages;
 totalram_pages = current_pages;

@@ -501,6 +507,7 @@ static int dealloc_pte_fn(
 pte_t *pte, struct page *pte_page, unsigned long addr, void *data)
 {
 unsigned long mfn = pte_mfn(*pte);
+ int ret;
 struct xen_memory_reservation reservation = {
 .extent_start = &mfn,
 .nr_extents = 1,

@@ -510,8 +517,8 @@ static int dealloc_pte_fn(
 set_pte_at(&init_mm, addr, pte, __pte_ma(0));

phys_to_machine_mapping[__pa(addr) >> PAGE_SHIFT] = INVALID_P2M_ENTRY;
- BUG_ON(HYPERVISOR_memory_op(
- XENMEM_decrease_reservation, &reservation) != 1);
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, &reservation);
+ BUG_ON(ret != 1);
return 0;
}

drivers/xen/balloon/balloon.c +4 -2

@@ -519,6 +526,7 @@ struct page *balloon_alloc_empty_page_ra
 {
 unsigned long vstart, flags;
 unsigned int order = get_order(nr_pages * PAGE_SIZE);
+ int ret;
 
 vstart = __get_free_pages(GFP_KERNEL, order);
 if (vstart == 0)

@@ -527,8 +535,9 @@ struct page *balloon_alloc_empty_page_ra
 scrub_pages(vstart, 1 << order);
 
 balloon_lock(flags);
- BUG_ON(generic_page_range(
- &init_mm, vstart, PAGE_SIZE << order, dealloc_pte_fn, NULL));
+ ret = generic_page_range(
+ &init_mm, vstart, PAGE_SIZE << order, dealloc_pte_fn, NULL);
+ BUG_ON(ret);
 current_pages -= 1UL << order;
 balloon_unlock(flags);
 

diff -purN linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c
--- linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c 2005-10-22 10:12:
23.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c 2005-10-27 11:16:
54.000000000 +0200

drivers/xen/blkback/blkback.c +10 -5

@@ -108,6 +108,7 @@ static void fast_flush_area(int idx, int
 struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 unsigned int i, invcount = 0;
 u16 handle;
+ int ret;
 
 for (i = 0; i < nr_pages; i++) {
 handle = pending_handle(idx, i);

@@ -120,8 +121,9 @@ static void fast_flush_area(int idx, int
 invcount++;
 }
 
- BUG_ON(HYPERVISOR_grant_table_op(
- GNTTABOP_unmap_grant_ref, unmap, invcount));
+ ret = HYPERVISOR_grant_table_op(
+ GNTTABOP_unmap_grant_ref, unmap, invcount);
+ BUG_ON(ret);
 }
 
 

@@ -338,6 +340,7 @@ static void dispatch_rw_block_io(blkif_t
 struct bio *bio = NULL, *biolist[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 int nbio = 0;
 request_queue_t *q;
+ int ret;
 
 /* Check that number of segments is sane. */
 nseg = req->nr_segments;

@@ -367,8 +370,8 @@ static void dispatch_rw_block_io(blkif_t
 map[i].flags |= GNTMAP_readonly;
 }
 
- BUG_ON(HYPERVISOR_grant_table_op(
- GNTTABOP_map_grant_ref, map, nseg));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg);
+ BUG_ON(ret);
 
 for (i = 0; i < nseg; i++) {
 if (unlikely(map[i].handle < 0)) {

@@ -493,6 +496,7 @@ static int __init blkif_init(void)
 {
 int i;
 struct page *page;
+ int ret;
 
 blkif_interface_init();
 

@@ -509,7 +513,8 @@ static int __init blkif_init(void)
 spin_lock_init(&blkio_schedule_list_lock);
 INIT_LIST_HEAD(&blkio_schedule_list);
 
- BUG_ON(kernel_thread(blkio_schedule, 0, CLONE_FS | CLONE_FILES) < 0);
+ ret = kernel_thread(blkio_schedule, 0, CLONE_FS | CLONE_FILES);
+ BUG_ON(ret < 0);
 
 blkif_xenbus_init();
 

diff -purN linux-2.6-xen-sparse/drivers/xen/blkback/interface.c linux-2.6-xen-sparse/drivers/xen/blkback/interface.c
--- linux-2.6-xen-sparse/drivers/xen/blkback/interface.c 2005-10-22 10:12:
24.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/blkback/interface.c 2005-10-27 11:17:
29.000000000 +0200

drivers/xen/blkback/interface.c +6 -2

@@ -31,6 +31,7 @@ blkif_t *alloc_blkif(domid_t domid)
 static int map_frontend_page(blkif_t *blkif, unsigned long shared_page)
 {
 struct gnttab_map_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)blkif->blk_ring_area->addr;
 op.flags = GNTMAP_host_map;

@@ -38,8 +39,9 @@ static int map_frontend_page(blkif_t *bl
 op.dom = blkif->domid;
 
 lock_vm_area(blkif->blk_ring_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
 unlock_vm_area(blkif->blk_ring_area);
+ BUG_ON(ret);
 
 if (op.handle < 0) {
 DPRINTK(" Grant table operation failure !\n");

@@ -55,14 +57,16 @@ static int map_frontend_page(blkif_t *bl
 static void unmap_frontend_page(blkif_t *blkif)
 {
 struct gnttab_unmap_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)blkif->blk_ring_area->addr;
 op.handle = blkif->shmem_handle;
 op.dev_bus_addr = 0;
 
 lock_vm_area(blkif->blk_ring_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
 unlock_vm_area(blkif->blk_ring_area);
+ BUG_ON(ret);
 }
 

int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn)
diff -purN linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
--- linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c 2005-10-22 10:12:
27.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c 2005-10-27 11:15:
41.000000000 +0200

drivers/xen/blkfront/blkfront.c +1 -0

@@ -305,6 +305,7 @@ static irqreturn_t blkif_int(int irq, vo
 
 for (i = info->ring.rsp_cons; i != rp; i++) {
 unsigned long id;
+ int ret;
 
 bret = RING_GET_RESPONSE(&info->ring, i);
 id = bret->id;

@@ -321,9 +322,10 @@ static irqreturn_t blkif_int(int irq, vo

DPRINTK("Bad return from blkdev data "
"request: %x\n", bret->status);

- BUG_ON(end_that_request_first(
+ ret = end_that_request_first(
req, (bret->status == BLKIF_RSP_OKAY),
- req->hard_nr_sectors));
+ req->hard_nr_sectors);
+ BUG_ON(ret);
end_that_request_last(req);
break;
default:
diff -purN linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c
--- linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c 2005-10-22 10:12:
30.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c 2005-10-27 11:19:
42.000000000 +0200

drivers/xen/blktap/blktap.c +8 -5

@@ -413,6 +413,7 @@ static void fast_flush_area(int idx, int
 unsigned int i, op = 0;
 struct grant_handle_pair *handle;
 unsigned long ptep;
+ int ret;
 
 for ( i = 0; i < nr_pages; i++)
 {

@@ -440,8 +441,8 @@ static void fast_flush_area(int idx, int
 BLKTAP_INVALIDATE_HANDLE(handle);
 }
 
- BUG_ON(HYPERVISOR_grant_table_op(
- GNTTABOP_unmap_grant_ref, unmap, op));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, op);
+ BUG_ON(ret);
 
 if (blktap_vma != NULL)
 zap_page_range(blktap_vma,

@@ -673,6 +674,7 @@ static void dispatch_rw_block_io(blkif_t
 struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST*2];
 int op, ret;
 unsigned int nseg;
+ int retval;
 
 /* Check that number of segments is sane. */
 nseg = req->nr_segments;

@@ -740,8 +742,8 @@ static void dispatch_rw_block_io(blkif_t
 op++;
 }
 
- BUG_ON(HYPERVISOR_grant_table_op(
- GNTTABOP_map_grant_ref, map, op));
+ retval = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, op);
+ BUG_ON(retval);
 
 op = 0;
 for (i = 0; i < (req->nr_segments*2); i += 2) {

@@ -877,7 +879,8 @@ static int __init blkif_init(void)
 spin_lock_init(&blkio_schedule_list_lock);
 INIT_LIST_HEAD(&blkio_schedule_list);
 
- BUG_ON(kernel_thread(blkio_schedule, 0, CLONE_FS | CLONE_FILES) < 0);
+ i = kernel_thread(blkio_schedule, 0, CLONE_FS | CLONE_FILES);
+ BUG_ON(i<0);
 
 blkif_xenbus_init();
 

diff -purN linux-2.6-xen-sparse/drivers/xen/blktap/interface.c linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
--- linux-2.6-xen-sparse/drivers/xen/blktap/interface.c 2005-10-22 10:12:
31.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/blktap/interface.c 2005-10-27 11:20:
19.000000000 +0200

drivers/xen/blkback/interface.c +6 -2

@@ -31,6 +31,7 @@ blkif_t *alloc_blkif(domid_t domid)
 static int map_frontend_page(blkif_t *blkif, unsigned long shared_page)
 {
 struct gnttab_map_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)blkif->blk_ring_area->addr;
 op.flags = GNTMAP_host_map;

@@ -38,8 +39,9 @@ static int map_frontend_page(blkif_t *bl
 op.dom = blkif->domid;
 
 lock_vm_area(blkif->blk_ring_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
 unlock_vm_area(blkif->blk_ring_area);
+ BUG_ON(ret);
 
 if (op.handle < 0) {
 DPRINTK(" Grant table operation failure !\n");

@@ -55,14 +57,16 @@ static int map_frontend_page(blkif_t *bl
 static void unmap_frontend_page(blkif_t *blkif)
 {
 struct gnttab_unmap_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)blkif->blk_ring_area->addr;
 op.handle = blkif->shmem_handle;
 op.dev_bus_addr = 0;
 
 lock_vm_area(blkif->blk_ring_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
 unlock_vm_area(blkif->blk_ring_area);
+ BUG_ON(ret);
 }
 

int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn)
diff -purN linux-2.6-xen-sparse/drivers/xen/evtchn/evtchn.c linux-2.6-xen-sparse/drivers/xen/evtchn/evtchn.c
--- linux-2.6-xen-sparse/drivers/xen/evtchn/evtchn.c 2005-10-22 10:12:
37.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/evtchn/evtchn.c 2005-10-27 11:27:
29.000000000 +0200

drivers/xen/evtchn/evtchn.c +6 -2

@@ -282,6 +282,7 @@ static int evtchn_ioctl(struct inode *in
 
 case IOCTL_EVTCHN_UNBIND: {
 struct ioctl_evtchn_unbind unbind;
+ int ret;
 
 rc = -EFAULT;
 if (copy_from_user(&unbind, (void *)arg, sizeof(unbind)))

@@ -306,7 +307,8 @@ static int evtchn_ioctl(struct inode *in
 
 op.cmd = EVTCHNOP_close;
 op.u.close.port = unbind.port;
- BUG_ON(HYPERVISOR_event_channel_op(&op));
+ ret = HYPERVISOR_event_channel_op(&op);
+ BUG_ON(ret);
 
 rc = 0;
 break;

@@ -399,6 +401,7 @@ static int evtchn_release(struct inode *
 
 for (i = 0; i < NR_EVENT_CHANNELS; i++)
 {
+ int ret;
 if (port_user[i] != u)
 continue;
 

@@ -407,7 +410,8 @@ static int evtchn_release(struct inode *
 
 op.cmd = EVTCHNOP_close;
 op.u.close.port = i;
- BUG_ON(HYPERVISOR_event_channel_op(&op));
+ ret = HYPERVISOR_event_channel_op(&op);
+ BUG_ON(ret);
 }
 
 spin_unlock_irq(&port_user_lock);

diff -purN linux-2.6-xen-sparse/drivers/xen/netback/interface.c linux-2.6-xen-sparse/drivers/xen/netback/interface.c
--- linux-2.6-xen-sparse/drivers/xen/netback/interface.c 2005-10-22 10:12:
38.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/netback/interface.c 2005-10-27 11:10:
20.000000000 +0200

drivers/xen/netback/interface.c +10 -4

@@ -115,6 +115,7 @@ static int map_frontend_pages(
 netif_t *netif, grant_ref_t tx_ring_ref, grant_ref_t rx_ring_ref)
 {
 struct gnttab_map_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)netif->comms_area->addr;
 op.flags = GNTMAP_host_map;

@@ -122,8 +123,9 @@ static int map_frontend_pages(
 op.dom = netif->domid;
 
 lock_vm_area(netif->comms_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
 unlock_vm_area(netif->comms_area);
+ BUG_ON(ret);
 
 if (op.handle < 0) {
 DPRINTK(" Gnttab failure mapping tx_ring_ref!\n");

@@ -139,8 +141,9 @@ static int map_frontend_pages(
 op.dom = netif->domid;
 
 lock_vm_area(netif->comms_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
 unlock_vm_area(netif->comms_area);
+ BUG_ON(ret);
 
 if (op.handle < 0) {
 DPRINTK(" Gnttab failure mapping rx_ring_ref!\n");

@@ -156,22 +159,25 @@ static int map_frontend_pages(
 static void unmap_frontend_pages(netif_t *netif)
 {
 struct gnttab_unmap_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)netif->comms_area->addr;
 op.handle = netif->tx_shmem_handle;
 op.dev_bus_addr = 0;
 
 lock_vm_area(netif->comms_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
 unlock_vm_area(netif->comms_area);
+ BUG_ON(ret);
 
 op.host_addr = (unsigned long)netif->comms_area->addr + PAGE_SIZE;
 op.handle = netif->rx_shmem_handle;
 op.dev_bus_addr = 0;
 
 lock_vm_area(netif->comms_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
 unlock_vm_area(netif->comms_area);
+ BUG_ON(ret);
 }
 
 int netif_map(netif_t *netif, unsigned long tx_ring_ref,

diff -purN linux-2.6-xen-sparse/drivers/xen/netback/netback.c linux-2.6-xen-sparse/drivers/xen/netback/netback.c
--- linux-2.6-xen-sparse/drivers/xen/netback/netback.c 2005-10-22 10:12:
39.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/netback/netback.c 2005-10-27 11:12:
42.000000000 +0200

drivers/xen/netback/netback.c +21 -10

@@ -112,9 +112,12 @@ static void free_mfn(unsigned long mfn)
 spin_lock_irqsave(&mfn_lock, flags);
 if ( alloc_index != MAX_MFN_ALLOC )
 mfn_list[alloc_index++] = mfn;
- else
- BUG_ON(HYPERVISOR_memory_op(XENMEM_decrease_reservation,
- &reservation) != 1);
+ else {
+ int ret;
+ ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
+ &reservation);
+ BUG_ON(ret != 1);
+ }
 spin_unlock_irqrestore(&mfn_lock, flags);
 }
 #endif

@@ -159,13 +162,15 @@ int netif_be_start_xmit(struct sk_buff *
 */
 if (skb_shared(skb) || skb_cloned(skb) || !is_xen_skb(skb)) {
 int hlen = skb->data - skb->head;
+ int ret;
 struct sk_buff *nskb = dev_alloc_skb(hlen + skb->len);
 if ( unlikely(nskb == NULL) )
 goto drop;
 skb_reserve(nskb, hlen);
 __skb_put(nskb, skb->len);
- BUG_ON(skb_copy_bits(skb, -hlen, nskb->data - hlen,
- skb->len + hlen));
+ ret = skb_copy_bits(skb, -hlen, nskb->data - hlen,
+ skb->len + hlen);
+ BUG_ON(ret);
 nskb->dev = skb->dev;
 nskb->proto_csum_valid = skb->proto_csum_valid;
 dev_kfree_skb(skb);

@@ -218,6 +223,7 @@ static void net_rx_action(unsigned long
 struct sk_buff *skb;
 u16 notify_list[NETIF_RX_RING_SIZE];
 int notify_nr = 0;
+ int ret;
 
 skb_queue_head_init(&rxq);
 

@@ -279,7 +285,8 @@ static void net_rx_action(unsigned long
 mcl++;
 
 mcl[-2].args[MULTI_UVMFLAGS_INDEX] = UVMF_TLB_FLUSH|UVMF_ALL;
- BUG_ON(HYPERVISOR_multicall(rx_mcl, mcl - rx_mcl) != 0);
+ ret = HYPERVISOR_multicall(rx_mcl, mcl - rx_mcl);
+ BUG_ON(ret != 0);
 
 mcl = rx_mcl;
 if( HYPERVISOR_grant_table_op(GNTTABOP_transfer, grant_rx_op,

@@ -421,6 +428,7 @@ inline static void net_tx_action_dealloc
 u16 pending_idx;
 PEND_RING_IDX dc, dp;
 netif_t *netif;
+ int ret;
 
 dc = dealloc_cons;
 dp = dealloc_prod;

@@ -436,8 +444,9 @@ inline static void net_tx_action_dealloc
 gop->handle = grant_tx_ref[pending_idx];
 gop++;
 }
- BUG_ON(HYPERVISOR_grant_table_op(
- GNTTABOP_unmap_grant_ref, tx_unmap_ops, gop - tx_unmap_ops));
+ ret = HYPERVISOR_grant_table_op(
+ GNTTABOP_unmap_grant_ref, tx_unmap_ops, gop - tx_unmap_ops);
+ BUG_ON(ret);
 
 while (dealloc_cons != dp) {
 pending_idx = dealloc_ring[MASK_PEND_IDX(dealloc_cons++)];

@@ -477,6 +486,7 @@ static void net_tx_action(unsigned long
 NETIF_RING_IDX i;
 gnttab_map_grant_ref_t *mop;
 unsigned int data_len;
+ int ret;
 
 if (dealloc_cons != dealloc_prod)
 net_tx_action_dealloc();

@@ -599,8 +609,9 @@ static void net_tx_action(unsigned long
 if (mop == tx_map_ops)
 return;
 
- BUG_ON(HYPERVISOR_grant_table_op(
- GNTTABOP_map_grant_ref, tx_map_ops, mop - tx_map_ops));
+ ret = HYPERVISOR_grant_table_op(
+ GNTTABOP_map_grant_ref, tx_map_ops, mop - tx_map_ops);
+ BUG_ON(ret);
 
 mop = tx_map_ops;
 while ((skb = __skb_dequeue(&tx_queue)) != NULL) {

diff -purN linux-2.6-xen-sparse/drivers/xen/tpmback/interface.c linux-2.6-xen-sparse/drivers/xen/tpmback/interface.c
--- linux-2.6-xen-sparse/drivers/xen/tpmback/interface.c 2005-10-22 10:13:
08.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/tpmback/interface.c 2005-10-27 11:28:
17.000000000 +0200

(quoted diff) +0 -0

@@ -78,6 +78,7 @@ tpmif_find(domid_t domid, long int insta

static int
map_frontend_page(tpmif_t *tpmif, unsigned long shared_page) {
+ int ret;
struct gnttab_map_grant_ref op = {
.host_addr = (unsigned long)tpmif->tx_area->addr, .flags = GNTMAP_host_map,

drivers/xen/tpmback/interface.c +5 -2

@@ -86,8 +87,9 @@ map_frontend_page(tpmif_t *tpmif, unsign
 };
 
 lock_vm_area(tpmif->tx_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1);
 unlock_vm_area(tpmif->tx_area);
+ BUG_ON(ret);
 
 if (op.handle < 0) {
 DPRINTK(" Grant table operation failure !\n");

@@ -104,14 +106,16 @@ static void
 unmap_frontend_page(tpmif_t *tpmif)
 {
 struct gnttab_unmap_grant_ref op;
+ int ret;
 
 op.host_addr = (unsigned long)tpmif->tx_area->addr;
 op.handle = tpmif->shmem_handle;
 op.dev_bus_addr = 0;
 
 lock_vm_area(tpmif->tx_area);
- BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1);
 unlock_vm_area(tpmif->tx_area);
+ BUG_ON(ret);
 }
 

int
diff -purN linux-2.6-xen-sparse/drivers/xen/util.c linux-2.6-xen-sparse /drivers/xen/util.c

drivers/xen/util.c 2005-10-27 11:28:49.000000000+0200 renamed from drivers/xen/util.c 2005-10-22 10:13:14.000000000+0200 +3 -1

@@ -34,7 +34,9 @@ struct vm_struct *alloc_vm_area(unsigned
 
 void free_vm_area(struct vm_struct *area)
 {
- BUG_ON(remove_vm_area(area->addr) != area);
+ struct vm_struct *ret;
+ ret = remove_vm_area(area->addr);
+ BUG_ON(ret != area);
 kfree(area);
 }
 

diff -purN linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c 2005-10-22 10:13:18.000000000 +0200
+++ linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c 2005-10-27 11:29:33.000000000 +0200

drivers/xen/util.c 2005-10-27 11:28:49.000000000+0200 renamed from drivers/xen/util.c 2005-10-22 10:13:14.000000000+0200 +3 -1

@@ -737,6 +737,7 @@ static int __init xenbus_probe_init(void
 
 unsigned long page;
 evtchn_op_t op = { 0 };
+ int ret;
 
 
 /* Allocate page. */

@@ -757,7 +758,8 @@ static int __init xenbus_probe_init(void
 op.u.alloc_unbound.dom = DOMID_SELF;
 op.u.alloc_unbound.remote_dom = 0;
 
- BUG_ON(HYPERVISOR_event_channel_op(&op));
+ ret = HYPERVISOR_event_channel_op(&op);
+ BUG_ON(ret);
 xen_start_info->store_evtchn = op.u.alloc_unbound.port;
 
 /* And finally publish the above info in /proc/xen */

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