From: Jason Gunthorpe jgg@mellanox.com
[ Upstream commit 3624a8f02568f08aef299d3b117f2226f621177d ]
Returning EOPNOTSUPP is problematic because it can also be returned by the method function, and we use it in quite a few places in drivers these days.
Instead, dedicate EPROTONOSUPPORT to indicate that the ioctl framework is enabled but the requested object and method are not supported by the kernel. No other case will return this code, and it lets userspace know to fall back to write().
grep says we do not use it today in drivers/infiniband subsystem.
Signed-off-by: Jason Gunthorpe jgg@mellanox.com Reviewed-by: Matan Barak matanb@mellanox.com Signed-off-by: Doug Ledford dledford@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- drivers/infiniband/core/uverbs_ioctl.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c index 71ff2644e053..d96dc1d17be1 100644 --- a/drivers/infiniband/core/uverbs_ioctl.c +++ b/drivers/infiniband/core/uverbs_ioctl.c @@ -243,16 +243,13 @@ static long ib_uverbs_cmd_verbs(struct ib_device *ib_dev, size_t ctx_size; uintptr_t data[UVERBS_OPTIMIZE_USING_STACK_SZ / sizeof(uintptr_t)];
- if (hdr->reserved) - return -EINVAL; - object_spec = uverbs_get_object(ib_dev, hdr->object_id); if (!object_spec) - return -EOPNOTSUPP; + return -EPROTONOSUPPORT;
method_spec = uverbs_get_method(object_spec, hdr->method_id); if (!method_spec) - return -EOPNOTSUPP; + return -EPROTONOSUPPORT;
if ((method_spec->flags & UVERBS_ACTION_FLAG_CREATE_ROOT) ^ !file->ucontext) return -EINVAL; @@ -305,6 +302,16 @@ static long ib_uverbs_cmd_verbs(struct ib_device *ib_dev,
err = uverbs_handle_method(buf, ctx->uattrs, hdr->num_attrs, ib_dev, file, method_spec, ctx->uverbs_attr_bundle); + + /* + * EPROTONOSUPPORT is ONLY to be returned if the ioctl framework can + * not invoke the method because the request is not supported. No + * other cases should return this code. + */ + if (unlikely(err == -EPROTONOSUPPORT)) { + WARN_ON_ONCE(err == -EPROTONOSUPPORT); + err = -EINVAL; + } out: if (ctx != (void *)data) kfree(ctx); @@ -341,7 +348,7 @@ long ib_uverbs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) }
if (hdr.reserved) { - err = -EOPNOTSUPP; + err = -EPROTONOSUPPORT; goto out; }