Re: [PATCH] Input: evdev: fix queueing of SYN_DROPPED event for EVIOCG[type] IOCTL case

Dear Mr. Dmitry Torokhov,

Could you please update about this patch?
Thank you.

-- Aniroop Mathur


On Wed, Dec 14, 2016 at 11:54 PM, Aniroop Mathur
[off-list ref] wrote:

Hello Mr. Torokhov,

Would you kindly update about this patch?
Thanks!

Best Regards,
Aniroop Mathur


On Fri, Nov 25, 2016 at 1:41 AM, Aniroop Mathur [off-list ref] wrote:

quoted

Currently, when EVIOCG[type] ioctl call is issued and bits_to_user fails,
then SYN_DROPPED event is inserted in the event queue always.

However, it is not compulsory that some events are flushed out on every
EVIOCG[type] ioctl call like in case of empty event queue and in case when
EVIOCG[type] ioctl is issued for say A type of events but event queue does
not have any A type of events but some other type of events.

Therefore, insert SYN_DROPPED event only when some events have been flushed
out from event queue plus bits_to_user fails.

Signed-off-by: Aniroop Mathur <redacted>
---
 drivers/input/evdev.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index e9ae3d5..f8b295e 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c

@@ -108,9 +108,11 @@ static bool __evdev_is_filtered(struct evdev_client *client,
 }

 /* flush queued events of type @type, caller must hold client->buffer_lock */
-static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
+static unsigned int __evdev_flush_queue(struct evdev_client *client,
+                                       unsigned int type)
 {
        unsigned int i, head, num;
+       unsigned int drop_count = 0;
        unsigned int mask = client->bufsize - 1;
        bool is_report;
        struct input_event *ev;

@@ -129,9 +131,11 @@ static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)

                if (ev->type == type) {
                        /* drop matched entry */
+                       drop_count++;
                        continue;
                } else if (is_report && !num) {
                        /* drop empty SYN_REPORT groups */
+                       drop_count++;
                        continue;
                } else if (head != i) {
                        /* move entry to fill the gap */

@@ -151,6 +155,7 @@ static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
        }

        client->head = head;
+       return drop_count;
 }

 static void __evdev_queue_syn_dropped(struct evdev_client *client)

@@ -920,6 +925,7 @@ static int evdev_handle_get_val(struct evdev_client *client,
        int ret;
        unsigned long *mem;
        size_t len;
+       unsigned int drop_count = 0;

        len = BITS_TO_LONGS(maxbit) * sizeof(unsigned long);
        mem = kmalloc(len, GFP_KERNEL);

@@ -933,12 +939,12 @@ static int evdev_handle_get_val(struct evdev_client *client,

        spin_unlock(&dev->event_lock);

-       __evdev_flush_queue(client, type);
+       drop_count = __evdev_flush_queue(client, type);

        spin_unlock_irq(&client->buffer_lock);

        ret = bits_to_user(mem, maxbit, maxlen, p, compat);
-       if (ret < 0)
+       if (ret < 0 && drop_count > 0)
                evdev_queue_syn_dropped(client);

        kfree(mem);
--

2.6.2