diff options
Diffstat (limited to 'drivers/xen/privcmd.c')
| -rw-r--r-- | drivers/xen/privcmd.c | 36 |
1 files changed, 25 insertions, 11 deletions
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c index 67dfa4778864..9563650dfbaf 100644 --- a/drivers/xen/privcmd.c +++ b/drivers/xen/privcmd.c @@ -17,6 +17,7 @@ #include <linux/poll.h> #include <linux/sched.h> #include <linux/slab.h> +#include <linux/srcu.h> #include <linux/string.h> #include <linux/workqueue.h> #include <linux/errno.h> @@ -48,6 +49,7 @@ #include "privcmd.h" +MODULE_DESCRIPTION("Xen hypercall passthrough driver"); MODULE_LICENSE("GPL"); #define PRIV_VMA_LOCKED ((void *)1) @@ -845,7 +847,8 @@ out: #ifdef CONFIG_XEN_PRIVCMD_EVENTFD /* Irqfd support */ static struct workqueue_struct *irqfd_cleanup_wq; -static DEFINE_MUTEX(irqfds_lock); +static DEFINE_SPINLOCK(irqfds_lock); +DEFINE_STATIC_SRCU(irqfds_srcu); static LIST_HEAD(irqfds_list); struct privcmd_kernel_irqfd { @@ -873,6 +876,9 @@ static void irqfd_shutdown(struct work_struct *work) container_of(work, struct privcmd_kernel_irqfd, shutdown); u64 cnt; + /* Make sure irqfd has been initialized in assign path */ + synchronize_srcu(&irqfds_srcu); + eventfd_ctx_remove_wait_queue(kirqfd->eventfd, &kirqfd->wait, &cnt); eventfd_ctx_put(kirqfd->eventfd); kfree(kirqfd); @@ -909,9 +915,11 @@ irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) irqfd_inject(kirqfd); if (flags & EPOLLHUP) { - mutex_lock(&irqfds_lock); + unsigned long flags; + + spin_lock_irqsave(&irqfds_lock, flags); irqfd_deactivate(kirqfd); - mutex_unlock(&irqfds_lock); + spin_unlock_irqrestore(&irqfds_lock, flags); } return 0; @@ -929,10 +937,11 @@ irqfd_poll_func(struct file *file, wait_queue_head_t *wqh, poll_table *pt) static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) { struct privcmd_kernel_irqfd *kirqfd, *tmp; + unsigned long flags; __poll_t events; struct fd f; void *dm_op; - int ret; + int ret, idx; kirqfd = kzalloc(sizeof(*kirqfd) + irqfd->size, GFP_KERNEL); if (!kirqfd) @@ -968,18 +977,19 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) init_waitqueue_func_entry(&kirqfd->wait, irqfd_wakeup); init_poll_funcptr(&kirqfd->pt, irqfd_poll_func); - mutex_lock(&irqfds_lock); + spin_lock_irqsave(&irqfds_lock, flags); list_for_each_entry(tmp, &irqfds_list, list) { if (kirqfd->eventfd == tmp->eventfd) { ret = -EBUSY; - mutex_unlock(&irqfds_lock); + spin_unlock_irqrestore(&irqfds_lock, flags); goto error_eventfd; } } + idx = srcu_read_lock(&irqfds_srcu); list_add_tail(&kirqfd->list, &irqfds_list); - mutex_unlock(&irqfds_lock); + spin_unlock_irqrestore(&irqfds_lock, flags); /* * Check if there was an event already pending on the eventfd before we @@ -989,6 +999,8 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) if (events & EPOLLIN) irqfd_inject(kirqfd); + srcu_read_unlock(&irqfds_srcu, idx); + /* * Do not drop the file until the kirqfd is fully initialized, otherwise * we might race against the EPOLLHUP. @@ -1011,12 +1023,13 @@ static int privcmd_irqfd_deassign(struct privcmd_irqfd *irqfd) { struct privcmd_kernel_irqfd *kirqfd; struct eventfd_ctx *eventfd; + unsigned long flags; eventfd = eventfd_ctx_fdget(irqfd->fd); if (IS_ERR(eventfd)) return PTR_ERR(eventfd); - mutex_lock(&irqfds_lock); + spin_lock_irqsave(&irqfds_lock, flags); list_for_each_entry(kirqfd, &irqfds_list, list) { if (kirqfd->eventfd == eventfd) { @@ -1025,7 +1038,7 @@ static int privcmd_irqfd_deassign(struct privcmd_irqfd *irqfd) } } - mutex_unlock(&irqfds_lock); + spin_unlock_irqrestore(&irqfds_lock, flags); eventfd_ctx_put(eventfd); @@ -1073,13 +1086,14 @@ static int privcmd_irqfd_init(void) static void privcmd_irqfd_exit(void) { struct privcmd_kernel_irqfd *kirqfd, *tmp; + unsigned long flags; - mutex_lock(&irqfds_lock); + spin_lock_irqsave(&irqfds_lock, flags); list_for_each_entry_safe(kirqfd, tmp, &irqfds_list, list) irqfd_deactivate(kirqfd); - mutex_unlock(&irqfds_lock); + spin_unlock_irqrestore(&irqfds_lock, flags); destroy_workqueue(irqfd_cleanup_wq); } |