x86,hyperv: Convert conn_to_evt to XArray

This IDR wasn't being used to allocate IDs, just as somewhere to store
pointers.  It moves out from under the protection of the mutex to its
own spinlock.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7b0a4ee7731312730338343bcb97c73fcdfed38e..8be6ec45e3871a39e27b3bcafe010382b3c6b49f 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -24,6 +24,7 @@
 #include <linux/clocksource.h>
 #include <linux/irqbypass.h>
 #include <linux/hyperv.h>
+#include <linux/xarray.h>
 
 #include <asm/apic.h>
 #include <asm/pvclock-abi.h>
@@ -833,7 +834,7 @@ struct kvm_hv {
 
        HV_REFERENCE_TSC_PAGE tsc_ref;
 
-       struct idr conn_to_evt;
+       struct xarray conn_to_evt;
 
        u64 hv_reenlightenment_control;
        u64 hv_tsc_emulation_control;

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index c10a8b10b203b706ce2b84b28e45fa0042bb1d77..0e595158a2dd6bec4489f6354fcd9e638bf4cc97 100644 (file)
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1579,10 +1579,7 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
        if (param & ~KVM_HYPERV_CONN_ID_MASK)
                return HV_STATUS_INVALID_HYPERCALL_INPUT;
 
-       /* the eventfd is protected by vcpu->kvm->srcu, but conn_to_evt isn't */
-       rcu_read_lock();
-       eventfd = idr_find(&vcpu->kvm->arch.hyperv.conn_to_evt, param);
-       rcu_read_unlock();
+       eventfd = xa_load(&vcpu->kvm->arch.hyperv.conn_to_evt, param);
        if (!eventfd)
                return HV_STATUS_INVALID_PORT_ID;
 
@@ -1713,17 +1710,17 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
 void kvm_hv_init_vm(struct kvm *kvm)
 {
        mutex_init(&kvm->arch.hyperv.hv_lock);
-       idr_init(&kvm->arch.hyperv.conn_to_evt);
+       xa_init(&kvm->arch.hyperv.conn_to_evt);
 }
 
 void kvm_hv_destroy_vm(struct kvm *kvm)
 {
        struct eventfd_ctx *eventfd;
-       int i;
+       unsigned long i;
 
-       idr_for_each_entry(&kvm->arch.hyperv.conn_to_evt, eventfd, i)
+       xa_for_each(&kvm->arch.hyperv.conn_to_evt, i, eventfd)
                eventfd_ctx_put(eventfd);
-       idr_destroy(&kvm->arch.hyperv.conn_to_evt);
+       xa_destroy(&kvm->arch.hyperv.conn_to_evt);
 }
 
 static int kvm_hv_eventfd_assign(struct kvm *kvm, u32 conn_id, int fd)
@@ -1736,17 +1733,10 @@ static int kvm_hv_eventfd_assign(struct kvm *kvm, u32 conn_id, int fd)
        if (IS_ERR(eventfd))
                return PTR_ERR(eventfd);
 
-       mutex_lock(&hv->hv_lock);
-       ret = idr_alloc(&hv->conn_to_evt, eventfd, conn_id, conn_id + 1,
-                       GFP_KERNEL_ACCOUNT);
-       mutex_unlock(&hv->hv_lock);
-
-       if (ret >= 0)
-               return 0;
+       ret = xa_insert(&hv->conn_to_evt, conn_id, eventfd, GFP_KERNEL_ACCOUNT);
+       if (ret < 0)
+               eventfd_ctx_put(eventfd);
 
-       if (ret == -ENOSPC)
-               ret = -EEXIST;
-       eventfd_ctx_put(eventfd);
        return ret;
 }
 
@@ -1755,10 +1745,7 @@ static int kvm_hv_eventfd_deassign(struct kvm *kvm, u32 conn_id)
        struct kvm_hv *hv = &kvm->arch.hyperv;
        struct eventfd_ctx *eventfd;
 
-       mutex_lock(&hv->hv_lock);
-       eventfd = idr_remove(&hv->conn_to_evt, conn_id);
-       mutex_unlock(&hv->hv_lock);
-
+       eventfd = xa_erase(&hv->conn_to_evt, conn_id);
        if (!eventfd)
                return -ENOENT;