| Message ID | ZFBg379uuHjf+YEM@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3516fa162a01f6611c3c129ce9529bdc720d36b7 |
| Headers | show |
| Series | Input: avoid calling input_set_abs_val() in the event handling core | expand |
On Mon, May 01, 2023 at 06:01:19PM -0700, Dmitry Torokhov wrote: > input_abs_set_val() can nominally call input_alloc_absinfo() which may > allocate memory with GFP_KERNEL flag. This does not happen when > input_abs_set_val() is called by the input core to set current MT slot when > handling a new input event, but it trips certain static analyzers. > > Rearrange the code to access the relevant structures directly. > > Reported-by: Teng Qi <starmiku1207184332@gmail.com> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> If git grep is to be believed, this is the only use of input_abs_set_val. Maybe removing that function is an option? Are there external drivers that rely on this (instead of sending an event)? Cheers, Peter > --- > drivers/input/input.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/input/input.c b/drivers/input/input.c > index 37e876d45eb9..f791d14ecf23 100644 > --- a/drivers/input/input.c > +++ b/drivers/input/input.c > @@ -190,6 +190,7 @@ static int input_handle_abs_event(struct input_dev *dev, > unsigned int code, int *pval) > { > struct input_mt *mt = dev->mt; > + bool is_new_slot = false; > bool is_mt_event; > int *pold; > > @@ -210,6 +211,7 @@ static int input_handle_abs_event(struct input_dev *dev, > pold = &dev->absinfo[code].value; > } else if (mt) { > pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST]; > + is_new_slot = mt->slot != dev->absinfo[ABS_MT_SLOT].value; > } else { > /* > * Bypass filtering for multi-touch events when > @@ -228,8 +230,8 @@ static int input_handle_abs_event(struct input_dev *dev, > } > > /* Flush pending "slot" event */ > - if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) { > - input_abs_set_val(dev, ABS_MT_SLOT, mt->slot); > + if (is_new_slot) { > + dev->absinfo[ABS_MT_SLOT].value = mt->slot; > return INPUT_PASS_TO_HANDLERS | INPUT_SLOT; > } > > -- > 2.40.1.495.gc816e09b53d-goog > > > -- > Dmitry
On Tue, May 02, 2023 at 04:05:31PM +1000, Peter Hutterer wrote: > On Mon, May 01, 2023 at 06:01:19PM -0700, Dmitry Torokhov wrote: > > input_abs_set_val() can nominally call input_alloc_absinfo() which may > > allocate memory with GFP_KERNEL flag. This does not happen when > > input_abs_set_val() is called by the input core to set current MT slot when > > handling a new input event, but it trips certain static analyzers. > > > > Rearrange the code to access the relevant structures directly. > > > > Reported-by: Teng Qi <starmiku1207184332@gmail.com> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > > Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> Thanks for the review. > > If git grep is to be believed, this is the only use of > input_abs_set_val. Maybe removing that function is an option? We generate input_abs_[get|set]_<item>() accessors and setters, and there is a couple of users of input_abs_get_val() in the code, so dropping just input_abs_set_val() is kind of hard. It might be useful elsewhere although I have no idea if anyone is actually using it anywhere... Thanks.
diff --git a/drivers/input/input.c b/drivers/input/input.c index 37e876d45eb9..f791d14ecf23 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -190,6 +190,7 @@ static int input_handle_abs_event(struct input_dev *dev, unsigned int code, int *pval) { struct input_mt *mt = dev->mt; + bool is_new_slot = false; bool is_mt_event; int *pold; @@ -210,6 +211,7 @@ static int input_handle_abs_event(struct input_dev *dev, pold = &dev->absinfo[code].value; } else if (mt) { pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST]; + is_new_slot = mt->slot != dev->absinfo[ABS_MT_SLOT].value; } else { /* * Bypass filtering for multi-touch events when @@ -228,8 +230,8 @@ static int input_handle_abs_event(struct input_dev *dev, } /* Flush pending "slot" event */ - if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) { - input_abs_set_val(dev, ABS_MT_SLOT, mt->slot); + if (is_new_slot) { + dev->absinfo[ABS_MT_SLOT].value = mt->slot; return INPUT_PASS_TO_HANDLERS | INPUT_SLOT; }
input_abs_set_val() can nominally call input_alloc_absinfo() which may allocate memory with GFP_KERNEL flag. This does not happen when input_abs_set_val() is called by the input core to set current MT slot when handling a new input event, but it trips certain static analyzers. Rearrange the code to access the relevant structures directly. Reported-by: Teng Qi <starmiku1207184332@gmail.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> --- drivers/input/input.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)