[PATCH 36/39] assorted variants of irqfd setup: convert to CLASS(fd)
From: viro@kernel.org
Date: 2024-07-30 05:15:20
Also in:
bpf, cgroups, kvm, linux-fsdevel
Subsystem:
acrn hypervisor service module, kernel virtual machine (kvm), the rest, vfio driver, xen hypervisor interface · Maintainers:
Fei Li, Paolo Bonzini, Linus Torvalds, Alex Williamson, Juergen Gross, Stefano Stabellini
From: Al Viro <viro@zeniv.linux.org.uk> in all of those failure exits prior to fdget() are plain returns and the only thing done after fdput() is (on failure exits) a kfree(), which can be done before fdput() just fine. NOTE: in acrn_irqfd_assign() 'fail:' failure exit is wrong for eventfd_ctx_fileget() failure (we only want fdput() there) and once we stop doing that, it doesn't need to check if eventfd is NULL or ERR_PTR(...) there. NOTE: in privcmd we move fdget() up before the allocation - more to the point, before the copy_from_user() attempt. [trivial conflict in privcmd] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- drivers/vfio/virqfd.c | 16 +++------------- drivers/virt/acrn/irqfd.c | 13 ++++--------- drivers/xen/privcmd.c | 17 ++++------------- virt/kvm/eventfd.c | 15 +++------------ 4 files changed, 14 insertions(+), 47 deletions(-)
diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c
index d22881245e89..aa2891f97508 100644
--- a/drivers/vfio/virqfd.c
+++ b/drivers/vfio/virqfd.c@@ -113,7 +113,6 @@ int vfio_virqfd_enable(void *opaque, void (*thread)(void *, void *), void *data, struct virqfd **pvirqfd, int fd) { - struct fd irqfd; struct eventfd_ctx *ctx; struct virqfd *virqfd; int ret = 0;
@@ -133,8 +132,8 @@ int vfio_virqfd_enable(void *opaque, INIT_WORK(&virqfd->inject, virqfd_inject); INIT_WORK(&virqfd->flush_inject, virqfd_flush_inject); - irqfd = fdget(fd); - if (!fd_file(irqfd)) { + CLASS(fd, irqfd)(fd); + if (fd_empty(irqfd)) { ret = -EBADF; goto err_fd; }
@@ -142,7 +141,7 @@ int vfio_virqfd_enable(void *opaque, ctx = eventfd_ctx_fileget(fd_file(irqfd)); if (IS_ERR(ctx)) { ret = PTR_ERR(ctx); - goto err_ctx; + goto err_fd; } virqfd->eventfd = ctx;
@@ -181,18 +180,9 @@ int vfio_virqfd_enable(void *opaque, if ((!handler || handler(opaque, data)) && thread) schedule_work(&virqfd->inject); } - - /* - * Do not drop the file until the irqfd is fully initialized, - * otherwise we might race against the EPOLLHUP. - */ - fdput(irqfd); - return 0; err_busy: eventfd_ctx_put(ctx); -err_ctx: - fdput(irqfd); err_fd: kfree(virqfd);
diff --git a/drivers/virt/acrn/irqfd.c b/drivers/virt/acrn/irqfd.c
index 9994d818bb7e..b7da24ca1475 100644
--- a/drivers/virt/acrn/irqfd.c
+++ b/drivers/virt/acrn/irqfd.c@@ -112,7 +112,6 @@ static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args) struct eventfd_ctx *eventfd = NULL; struct hsm_irqfd *irqfd, *tmp; __poll_t events; - struct fd f; int ret = 0; irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
@@ -124,8 +123,8 @@ static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args) INIT_LIST_HEAD(&irqfd->list); INIT_WORK(&irqfd->shutdown, hsm_irqfd_shutdown_work); - f = fdget(args->fd); - if (!fd_file(f)) { + CLASS(fd, f)(args->fd); + if (fd_empty(f)) { ret = -EBADF; goto out; }
@@ -133,7 +132,7 @@ static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args) eventfd = eventfd_ctx_fileget(fd_file(f)); if (IS_ERR(eventfd)) { ret = PTR_ERR(eventfd); - goto fail; + goto out; } irqfd->eventfd = eventfd;
@@ -162,13 +161,9 @@ static int acrn_irqfd_assign(struct acrn_vm *vm, struct acrn_irqfd *args) if (events & EPOLLIN) acrn_irqfd_inject(irqfd); - fdput(f); return 0; fail: - if (eventfd && !IS_ERR(eventfd)) - eventfd_ctx_put(eventfd); - - fdput(f); + eventfd_ctx_put(eventfd); out: kfree(irqfd); return ret;
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index ba02b732fa49..8a5bdf1f3050 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c@@ -939,10 +939,11 @@ 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, idx; + CLASS(fd, f)(irqfd->fd); + kirqfd = kzalloc(sizeof(*kirqfd) + irqfd->size, GFP_KERNEL); if (!kirqfd) return -ENOMEM;
@@ -958,8 +959,7 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) kirqfd->dom = irqfd->dom; INIT_WORK(&kirqfd->shutdown, irqfd_shutdown); - f = fdget(irqfd->fd); - if (!fd_file(f)) { + if (fd_empty(f)) { ret = -EBADF; goto error_kfree; }
@@ -967,7 +967,7 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) kirqfd->eventfd = eventfd_ctx_fileget(fd_file(f)); if (IS_ERR(kirqfd->eventfd)) { ret = PTR_ERR(kirqfd->eventfd); - goto error_fd_put; + goto error_kfree; } /*
@@ -1000,20 +1000,11 @@ static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd) 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. - */ - fdput(f); return 0; error_eventfd: eventfd_ctx_put(kirqfd->eventfd); -error_fd_put: - fdput(f); - error_kfree: kfree(kirqfd); return ret;
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 65efb3735e79..70bc0d1f5f6a 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c@@ -303,7 +303,6 @@ static int kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) { struct kvm_kernel_irqfd *irqfd, *tmp; - struct fd f; struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; int ret; __poll_t events;
@@ -326,8 +325,8 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) INIT_WORK(&irqfd->shutdown, irqfd_shutdown); seqcount_spinlock_init(&irqfd->irq_entry_sc, &kvm->irqfds.lock); - f = fdget(args->fd); - if (!fd_file(f)) { + CLASS(fd, f)(args->fd); + if (fd_empty(f)) { ret = -EBADF; goto out; }
@@ -335,7 +334,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) eventfd = eventfd_ctx_fileget(fd_file(f)); if (IS_ERR(eventfd)) { ret = PTR_ERR(eventfd); - goto fail; + goto out; } irqfd->eventfd = eventfd;
@@ -439,12 +438,6 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) #endif srcu_read_unlock(&kvm->irq_srcu, idx); - - /* - * do not drop the file until the irqfd is fully initialized, otherwise - * we might race against the EPOLLHUP - */ - fdput(f); return 0; fail:
@@ -457,8 +450,6 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) if (eventfd && !IS_ERR(eventfd)) eventfd_ctx_put(eventfd); - fdput(f); - out: kfree(irqfd); return ret;
--
2.39.2