diff options
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/xen/events/events_base.c | 16 | ||||
| -rw-r--r-- | drivers/xen/evtchn.c | 35 | ||||
| -rw-r--r-- | drivers/xen/grant-dma-ops.c | 2 | ||||
| -rw-r--r-- | drivers/xen/grant-table.c | 42 | ||||
| -rw-r--r-- | drivers/xen/privcmd.c | 282 | ||||
| -rw-r--r-- | drivers/xen/swiotlb-xen.c | 2 | ||||
| -rw-r--r-- | drivers/xen/xen-acpi-processor.c | 7 | ||||
| -rw-r--r-- | drivers/xen/xen-pciback/conf_space_quirks.h | 2 | ||||
| -rw-r--r-- | drivers/xen/xen-pciback/pciback.h | 3 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_probe.c | 3 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_probe_frontend.c | 2 | ||||
| -rw-r--r-- | drivers/xen/xenbus/xenbus_xs.c | 4 |
13 files changed, 359 insertions, 48 deletions
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index d5d7c402b651..d43153fec18e 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -269,6 +269,13 @@ config XEN_PRIVCMD disaggregated Xen setups this driver might be needed for other domains, too. +config XEN_PRIVCMD_IRQFD + bool "Xen irqfd support" + depends on XEN_PRIVCMD && XEN_VIRTIO && EVENTFD + help + Using the irqfd mechanism a virtio backend running in a daemon can + speed up interrupt injection into a guest. + config XEN_ACPI_PROCESSOR tristate "Xen ACPI processor" depends on XEN && XEN_PV_DOM0 && X86 && ACPI_PROCESSOR && CPU_FREQ diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index c7715f8bd452..3bdd5b59661d 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -112,6 +112,7 @@ struct irq_info { unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */ u64 eoi_time; /* Time in jiffies when to EOI. */ raw_spinlock_t lock; + bool is_static; /* Is event channel static */ union { unsigned short virq; @@ -815,15 +816,6 @@ static void xen_free_irq(unsigned irq) irq_free_desc(irq); } -static void xen_evtchn_close(evtchn_port_t port) -{ - struct evtchn_close close; - - close.port = port; - if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0) - BUG(); -} - /* Not called for lateeoi events. */ static void event_handler_exit(struct irq_info *info) { @@ -982,7 +974,8 @@ static void __unbind_from_irq(unsigned int irq) unsigned int cpu = cpu_from_irq(irq); struct xenbus_device *dev; - xen_evtchn_close(evtchn); + if (!info->is_static) + xen_evtchn_close(evtchn); switch (type_from_irq(irq)) { case IRQT_VIRQ: @@ -1574,7 +1567,7 @@ int xen_set_irq_priority(unsigned irq, unsigned priority) } EXPORT_SYMBOL_GPL(xen_set_irq_priority); -int evtchn_make_refcounted(evtchn_port_t evtchn) +int evtchn_make_refcounted(evtchn_port_t evtchn, bool is_static) { int irq = get_evtchn_to_irq(evtchn); struct irq_info *info; @@ -1590,6 +1583,7 @@ int evtchn_make_refcounted(evtchn_port_t evtchn) WARN_ON(info->refcnt != -1); info->refcnt = 1; + info->is_static = is_static; return 0; } diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index c99415a70051..9139a7364df5 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -366,10 +366,10 @@ static int evtchn_resize_ring(struct per_user_data *u) return 0; } -static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port) +static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port, + bool is_static) { struct user_evtchn *evtchn; - struct evtchn_close close; int rc = 0; /* @@ -402,14 +402,14 @@ static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port) if (rc < 0) goto err; - rc = evtchn_make_refcounted(port); + rc = evtchn_make_refcounted(port, is_static); return rc; err: /* bind failed, should close the port now */ - close.port = port; - if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0) - BUG(); + if (!is_static) + xen_evtchn_close(port); + del_evtchn(u, evtchn); return rc; } @@ -456,7 +456,7 @@ static long evtchn_ioctl(struct file *file, if (rc != 0) break; - rc = evtchn_bind_to_user(u, bind_virq.port); + rc = evtchn_bind_to_user(u, bind_virq.port, false); if (rc == 0) rc = bind_virq.port; break; @@ -482,7 +482,7 @@ static long evtchn_ioctl(struct file *file, if (rc != 0) break; - rc = evtchn_bind_to_user(u, bind_interdomain.local_port); + rc = evtchn_bind_to_user(u, bind_interdomain.local_port, false); if (rc == 0) rc = bind_interdomain.local_port; break; @@ -507,7 +507,7 @@ static long evtchn_ioctl(struct file *file, if (rc != 0) break; - rc = evtchn_bind_to_user(u, alloc_unbound.port); + rc = evtchn_bind_to_user(u, alloc_unbound.port, false); if (rc == 0) rc = alloc_unbound.port; break; @@ -536,6 +536,23 @@ static long evtchn_ioctl(struct file *file, break; } + case IOCTL_EVTCHN_BIND_STATIC: { + struct ioctl_evtchn_bind bind; + struct user_evtchn *evtchn; + + rc = -EFAULT; + if (copy_from_user(&bind, uarg, sizeof(bind))) + break; + + rc = -EISCONN; + evtchn = find_evtchn(u, bind.port); + if (evtchn) + break; + + rc = evtchn_bind_to_user(u, bind.port, true); + break; + } + case IOCTL_EVTCHN_NOTIFY: { struct ioctl_evtchn_notify notify; struct user_evtchn *evtchn; diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index 9784a77fa3c9..76f6f26265a3 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -303,6 +303,8 @@ static struct device_node *xen_dt_get_node(struct device *dev) while (!pci_is_root_bus(bus)) bus = bus->parent; + if (!bus->bridge->parent) + return NULL; return of_node_get(bus->bridge->parent->of_node); } diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index e1ec725c2819..35659bf70746 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -498,14 +498,21 @@ static LIST_HEAD(deferred_list); static void gnttab_handle_deferred(struct timer_list *); static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred); +static atomic64_t deferred_count; +static atomic64_t leaked_count; +static unsigned int free_per_iteration = 10; +module_param(free_per_iteration, uint, 0600); + static void gnttab_handle_deferred(struct timer_list *unused) { - unsigned int nr = 10; + unsigned int nr = READ_ONCE(free_per_iteration); + const bool ignore_limit = nr == 0; struct deferred_entry *first = NULL; unsigned long flags; + size_t freed = 0; spin_lock_irqsave(&gnttab_list_lock, flags); - while (nr--) { + while ((ignore_limit || nr--) && !list_empty(&deferred_list)) { struct deferred_entry *entry = list_first_entry(&deferred_list, struct deferred_entry, list); @@ -515,10 +522,14 @@ static void gnttab_handle_deferred(struct timer_list *unused) list_del(&entry->list); spin_unlock_irqrestore(&gnttab_list_lock, flags); if (_gnttab_end_foreign_access_ref(entry->ref)) { + uint64_t ret = atomic64_dec_return(&deferred_count); + put_free_entry(entry->ref); - pr_debug("freeing g.e. %#x (pfn %#lx)\n", - entry->ref, page_to_pfn(entry->page)); + pr_debug("freeing g.e. %#x (pfn %#lx), %llu remaining\n", + entry->ref, page_to_pfn(entry->page), + (unsigned long long)ret); put_page(entry->page); + freed++; kfree(entry); entry = NULL; } else { @@ -530,21 +541,22 @@ static void gnttab_handle_deferred(struct timer_list *unused) spin_lock_irqsave(&gnttab_list_lock, flags); if (entry) list_add_tail(&entry->list, &deferred_list); - else if (list_empty(&deferred_list)) - break; } - if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) { + if (list_empty(&deferred_list)) + WARN_ON(atomic64_read(&deferred_count)); + else if (!timer_pending(&deferred_timer)) { deferred_timer.expires = jiffies + HZ; add_timer(&deferred_timer); } spin_unlock_irqrestore(&gnttab_list_lock, flags); + pr_debug("Freed %zu references", freed); } static void gnttab_add_deferred(grant_ref_t ref, struct page *page) { struct deferred_entry *entry; gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL; - const char *what = KERN_WARNING "leaking"; + uint64_t leaked, deferred; entry = kmalloc(sizeof(*entry), gfp); if (!page) { @@ -567,10 +579,16 @@ static void gnttab_add_deferred(grant_ref_t ref, struct page *page) add_timer(&deferred_timer); } spin_unlock_irqrestore(&gnttab_list_lock, flags); - what = KERN_DEBUG "deferring"; + deferred = atomic64_inc_return(&deferred_count); + leaked = atomic64_read(&leaked_count); + pr_debug("deferring g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n", + ref, page ? page_to_pfn(page) : -1, deferred, leaked); + } else { + deferred = atomic64_read(&deferred_count); + leaked = atomic64_inc_return(&leaked_count); + pr_warn("leaking g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n", + ref, page ? page_to_pfn(page) : -1, deferred, leaked); } - printk("%s g.e. %#x (pfn %#lx)\n", - what, ref, page ? page_to_pfn(page) : -1); } int gnttab_try_end_foreign_access(grant_ref_t ref) @@ -1026,7 +1044,7 @@ EXPORT_SYMBOL_GPL(gnttab_pages_clear_private); /** * gnttab_free_pages - free pages allocated by gnttab_alloc_pages() - * @nr_pages; number of pages to free + * @nr_pages: number of pages to free * @pages: the pages */ void gnttab_free_pages(int nr_pages, struct page **pages) diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index f447cd37cc4c..f00ad5f5f1d4 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -9,11 +9,16 @@ #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt +#include <linux/eventfd.h> +#include <linux/file.h> #include <linux/kernel.h> #include <linux/module.h> +#include <linux/mutex.h> +#include <linux/poll.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/workqueue.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/mman.h> @@ -833,6 +838,263 @@ out: return rc; } +#ifdef CONFIG_XEN_PRIVCMD_IRQFD +/* Irqfd support */ +static struct workqueue_struct *irqfd_cleanup_wq; +static DEFINE_MUTEX(irqfds_lock); +static LIST_HEAD(irqfds_list); + +struct privcmd_kernel_irqfd { + struct xen_dm_op_buf xbufs; + domid_t dom; + bool error; + struct eventfd_ctx *eventfd; + struct work_struct shutdown; + wait_queue_entry_t wait; + struct list_head list; + poll_table pt; +}; + +static void irqfd_deactivate(struct privcmd_kernel_irqfd *kirqfd) +{ + lockdep_assert_held(&irqfds_lock); + + list_del_init(&kirqfd->list); + queue_work(irqfd_cleanup_wq, &kirqfd->shutdown); +} + +static void irqfd_shutdown(struct work_struct *work) +{ + struct privcmd_kernel_irqfd *kirqfd = + container_of(work, struct privcmd_kernel_irqfd, shutdown); + u64 cnt; + + eventfd_ctx_remove_wait_queue(kirqfd->eventfd, &kirqfd->wait, &cnt); + eventfd_ctx_put(kirqfd->eventfd); + kfree(kirqfd); +} + +static void irqfd_inject(struct privcmd_kernel_irqfd *kirqfd) +{ + u64 cnt; + long rc; + + eventfd_ctx_do_read(kirqfd->eventfd, &cnt); + + xen_preemptible_hcall_begin(); + rc = HYPERVISOR_dm_op(kirqfd->dom, 1, &kirqfd->xbufs); + xen_preemptible_hcall_end(); + + /* Don't repeat the error message for consecutive failures */ + if (rc && !kirqfd->error) { + pr_err("Failed to configure irq for guest domain: %d\n", + kirqfd->dom); + } + + kirqfd->error = rc; +} + +static int +irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) +{ + struct privcmd_kernel_irqfd *kirqfd = + container_of(wait, struct privcmd_kernel_irqfd, wait); + __poll_t flags = key_to_poll(key); + + if (flags & EPOLLIN) + irqfd_inject(kirqfd); + + if (flags & EPOLLHUP) { + mutex_lock(&irqfds_lock); + irqfd_deactivate(kirqfd); + mutex_unlock(&irqfds_lock); + } + + return 0; +} + +static void +irqfd_poll_func(struct file *file, wait_queue_head_t *wqh, poll_table *pt) +{ + struct privcmd_kernel_irqfd *kirqfd = + container_of(pt, struct privcmd_kernel_irqfd, pt); + + add_wait_queue_priority(wqh, &kirqfd->wait); +} + +static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) +{ + struct privcmd_kernel_irqfd *kirqfd, *tmp; + __poll_t events; + struct fd f; + void *dm_op; + int ret; + + kirqfd = kzalloc(sizeof(*kirqfd) + irqfd->size, GFP_KERNEL); + if (!kirqfd) + return -ENOMEM; + dm_op = kirqfd + 1; + + if (copy_from_user(dm_op, irqfd->dm_op, irqfd->size)) { + ret = -EFAULT; + goto error_kfree; + } + + kirqfd->xbufs.size = irqfd->size; + set_xen_guest_handle(kirqfd->xbufs.h, dm_op); + kirqfd->dom = irqfd->dom; + INIT_WORK(&kirqfd->shutdown, irqfd_shutdown); + + f = fdget(irqfd->fd); + if (!f.file) { + ret = -EBADF; + goto error_kfree; + } + + kirqfd->eventfd = eventfd_ctx_fileget(f.file); + if (IS_ERR(kirqfd->eventfd)) { + ret = PTR_ERR(kirqfd->eventfd); + goto error_fd_put; + } + + /* + * Install our own custom wake-up handling so we are notified via a + * callback whenever someone signals the underlying eventfd. + */ + init_waitqueue_func_entry(&kirqfd->wait, irqfd_wakeup); + init_poll_funcptr(&kirqfd->pt, irqfd_poll_func); + + mutex_lock(&irqfds_lock); + + list_for_each_entry(tmp, &irqfds_list, list) { + if (kirqfd->eventfd == tmp->eventfd) { + ret = -EBUSY; + mutex_unlock(&irqfds_lock); + goto error_eventfd; + } + } + + list_add_tail(&kirqfd->list, &irqfds_list); + mutex_unlock(&irqfds_lock); + + /* + * Check if there was an event already pending on the eventfd before we + * registered, and trigger it as if we didn't miss it. + */ + events = vfs_poll(f.file, &kirqfd->pt); + if (events & EPOLLIN) + irqfd_inject(kirqfd); + + /* + * Do not drop the file until the kirqfd is fully initialized, otherwise + * we might race against the EPOLLHUP. + */ + fdput(f); + return 0; + +error_eventfd: + eventfd_ctx_put(kirqfd->eventfd); + +error_fd_put: + fdput(f); + +error_kfree: + kfree(kirqfd); + return ret; +} + +static int privcmd_irqfd_deassign(struct privcmd_irqfd *irqfd) +{ + struct privcmd_kernel_irqfd *kirqfd; + struct eventfd_ctx *eventfd; + + eventfd = eventfd_ctx_fdget(irqfd->fd); + if (IS_ERR(eventfd)) + return PTR_ERR(eventfd); + + mutex_lock(&irqfds_lock); + + list_for_each_entry(kirqfd, &irqfds_list, list) { + if (kirqfd->eventfd == eventfd) { + irqfd_deactivate(kirqfd); + break; + } + } + + mutex_unlock(&irqfds_lock); + + eventfd_ctx_put(eventfd); + + /* + * Block until we know all outstanding shutdown jobs have completed so + * that we guarantee there will not be any more interrupts once this + * deassign function returns. + */ + flush_workqueue(irqfd_cleanup_wq); + + return 0; +} + +static long privcmd_ioctl_irqfd(struct file *file, void __user *udata) +{ + struct privcmd_data *data = file->private_data; + struct privcmd_irqfd irqfd; + + if (copy_from_user(&irqfd, udata, sizeof(irqfd))) + return -EFAULT; + + /* No other flags should be set */ + if (irqfd.flags & ~PRIVCMD_IRQFD_FLAG_DEASSIGN) + return -EINVAL; + + /* If restriction is in place, check the domid matches */ + if (data->domid != DOMID_INVALID && data->domid != irqfd.dom) + return -EPERM; + + if (irqfd.flags & PRIVCMD_IRQFD_FLAG_DEASSIGN) + return privcmd_irqfd_deassign(&irqfd); + + return privcmd_irqfd_assign(&irqfd); +} + +static int privcmd_irqfd_init(void) +{ + irqfd_cleanup_wq = alloc_workqueue("privcmd-irqfd-cleanup", 0, 0); + if (!irqfd_cleanup_wq) + return -ENOMEM; + + return 0; +} + +static void privcmd_irqfd_exit(void) +{ + struct privcmd_kernel_irqfd *kirqfd, *tmp; + + mutex_lock(&irqfds_lock); + + list_for_each_entry_safe(kirqfd, tmp, &irqfds_list, list) + irqfd_deactivate(kirqfd); + + mutex_unlock(&irqfds_lock); + + destroy_workqueue(irqfd_cleanup_wq); +} +#else +static inline long privcmd_ioctl_irqfd(struct file *file, void __user *udata) +{ + return -EOPNOTSUPP; +} + +static inline int privcmd_irqfd_init(void) +{ + return 0; +} + +static inline void privcmd_irqfd_exit(void) +{ +} +#endif /* CONFIG_XEN_PRIVCMD_IRQFD */ + static long privcmd_ioctl(struct file *file, unsigned int cmd, unsigned long data) { @@ -868,6 +1130,10 @@ static long privcmd_ioctl(struct file *file, ret = privcmd_ioctl_mmap_resource(file, udata); break; + case IOCTL_PRIVCMD_IRQFD: + ret = privcmd_ioctl_irqfd(file, udata); + break; + default: break; } @@ -992,15 +1258,27 @@ static int __init privcmd_init(void) err = misc_register(&xen_privcmdbuf_dev); if (err != 0) { pr_err("Could not register Xen hypercall-buf device\n"); - misc_deregister(&privcmd_dev); - return err; + goto err_privcmdbuf; + } + + err = privcmd_irqfd_init(); + if (err != 0) { + pr_err("irqfd init failed\n"); + goto err_irqfd; } return 0; + +err_irqfd: + misc_deregister(&xen_privcmdbuf_dev); +err_privcmdbuf: + misc_deregister(&privcmd_dev); + return err; } static void __exit privcmd_exit(void) { + privcmd_irqfd_exit(); misc_deregister(&privcmd_dev); misc_deregister(&xen_privcmdbuf_dev); } diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 67aa74d20162..946bd56f0ac5 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -381,7 +381,7 @@ xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl, static int xen_swiotlb_dma_supported(struct device *hwdev, u64 mask) { - return xen_phys_to_dma(hwdev, io_tlb_default_mem.end - 1) <= mask; + return xen_phys_to_dma(hwdev, default_swiotlb_limit()) <= mask; } const struct dma_map_ops xen_swiotlb_dma_ops = { diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c index 9cb61db67efd..296703939846 100644 --- a/drivers/xen/xen-acpi-processor.c +++ b/drivers/xen/xen-acpi-processor.c @@ -473,11 +473,8 @@ static int xen_upload_processor_pm_data(void) if (!_pr) continue; - if (!pr_backup) { - pr_backup = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL); - if (pr_backup) - memcpy(pr_backup, _pr, sizeof(struct acpi_processor)); - } + if (!pr_backup) + pr_backup = kmemdup(_pr, sizeof(*_pr), GFP_KERNEL); (void)upload_pm_data(_pr); } diff --git a/drivers/xen/xen-pciback/conf_space_quirks.h b/drivers/xen/xen-pciback/conf_space_quirks.h index d873abe35bf6..fc1557dfef49 100644 --- a/drivers/xen/xen-pciback/conf_space_quirks.h +++ b/drivers/xen/xen-pciback/conf_space_quirks.h @@ -21,8 +21,6 @@ struct xen_pcibk_config_quirk { int xen_pcibk_config_quirks_add_field(struct pci_dev *dev, struct config_field *field); -int xen_pcibk_config_quirks_remove_field(struct pci_dev *dev, int reg); - int xen_pcibk_config_quirks_init(struct pci_dev *dev); void xen_pcibk_config_field_free(struct config_field *field); diff --git a/drivers/xen/xen-pciback/pciback.h b/drivers/xen/xen-pciback/pciback.h index 9a64196e831d..f9599ed2f2e2 100644 --- a/drivers/xen/xen-pciback/pciback.h +++ b/drivers/xen/xen-pciback/pciback.h @@ -201,6 +201,3 @@ static inline void xen_pcibk_lateeoi(struct xen_pcibk_device *pdev, int xen_pcibk_xenbus_register(void); void xen_pcibk_xenbus_unregister(void); #endif - -/* Handles shared IRQs that can to device domain and control domain. */ -void xen_pcibk_irq_handler(struct pci_dev *dev, int reset); diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index 58b732dcbfb8..639bf628389b 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -811,6 +811,9 @@ static int xenbus_probe_thread(void *unused) static int __init xenbus_probe_initcall(void) { + if (!xen_domain()) + return -ENODEV; + /* * Probe XenBus here in the XS_PV case, and also XS_HVM unless we * need to wait for the platform PCI device to come up or diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c index 3f3836cb7279..fcb335bb7b18 100644 --- a/drivers/xen/xenbus/xenbus_probe_frontend.c +++ b/drivers/xen/xenbus/xenbus_probe_frontend.c @@ -429,7 +429,7 @@ static void xenbus_check_frontend(char *class, char *dev) printk(KERN_DEBUG "XENBUS: frontend %s %s\n", frontend, xenbus_strstate(fe_state)); backend = xenbus_read(XBT_NIL, frontend, "backend", NULL); - if (!backend || IS_ERR(backend)) + if (IS_ERR_OR_NULL(backend)) goto out; err = xenbus_scanf(XBT_NIL, backend, "state", "%i", &be_state); if (err == 1) diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c index 12e02eb01f59..028a182bcc9e 100644 --- a/drivers/xen/xenbus/xenbus_xs.c +++ b/drivers/xen/xenbus/xenbus_xs.c @@ -840,8 +840,8 @@ void xs_suspend(void) { xs_suspend_enter(); - down_write(&xs_watch_rwsem); mutex_lock(&xs_response_mutex); + down_write(&xs_watch_rwsem); } void xs_resume(void) @@ -866,8 +866,8 @@ void xs_resume(void) void xs_suspend_cancel(void) { - mutex_unlock(&xs_response_mutex); up_write(&xs_watch_rwsem); + mutex_unlock(&xs_response_mutex); xs_suspend_exit(); } |