From fc7392aa1b20debc7f398acc39ffc817630f11e6 Mon Sep 17 00:00:00 2001 From: Elias Vanderstuyft Date: Sat, 29 Mar 2014 12:08:45 -0700 Subject: [PATCH] Input: don't modify the id of ioctl-provided ff effect on upload failure If a new (id == -1) ff effect was uploaded from userspace, ff-core.c::input_ff_upload() will have assigned a positive number to the new effect id. Currently, evdev.c::evdev_do_ioctl() will save this new id to userspace, regardless of whether the upload succeeded or not. On upload failure, this can be confusing because the dev->ff->effects[] array will not contain an element at the index of that new effect id. This patch fixes this by leaving the id unchanged after upload fails. Note: Unfortunately applications should still expect changed effect id for quite some time. This has been discussed on: http://www.mail-archive.com/linux-input@vger.kernel.org/msg08513.html ("ff-core effect id handling in case of a failed effect upload") Suggested-by: Dmitry Torokhov Signed-off-by: Elias Vanderstuyft Signed-off-by: Dmitry Torokhov --- drivers/input/evdev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index a06e12552886..ce953d895f5b 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -954,11 +954,13 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd, return -EFAULT; error = input_ff_upload(dev, &effect, file); + if (error) + return error; if (put_user(effect.id, &(((struct ff_effect __user *)p)->id))) return -EFAULT; - return error; + return 0; } /* Multi-number variable-length handlers */