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 <dmitry.torok...@gmail.com> Signed-off-by: Elias Vanderstuyft <elias....@gmail.com> Cc: Anssi Hannula <anssi.hann...@iki.fi> Cc: Michal Malý <madcatxs...@devoid-pointer.net> Cc: linux-in...@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- v2: Only added one line to the commit message to say what this patch actually does, instead of only stating the reason why it's submitted. 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 a06e125..ce953d8 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 */ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
