| Message ID | alpine.LNX.2.00.1304171041070.31201@pobox.suse.cz (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Jiri Kosina |
| Headers | show |
On 04/17/2013 07:44 PM, Jiri Kosina wrote: > On Wed, 17 Apr 2013, Benjamin Tissoires wrote: > >> Hi Jiri, >> >> This is a small rework of the HID debugfs. >> I encountered a problem with multitouch devices: they have too much usages to >> fit into the fixed size output buffer of 512. >> So I digg a little, and end up with those 4 patches. > > Hi Benjamin, > > thanks, I will look into it and see whether I would be able to apply it > still for 3.10 merge window. Thanks. I think patches 1 and 2 of this series are pretty straightforward. Patches 3 and 4 will maybe require a little bit more attention. I don't mind if it's postponed to 3.11 (given the long time this has been broken for devices with big reports). I just need to access HID debugfs for hid-replay when hidraw does not send anything. But as I'm also willing to use hid-replay with current kernels, I still need a way to use the best option (hidraw or hid debugfs) for current kernels. > > I also have a locking fix for HID-debugfs which I am going to apply > shortly, but I am travelling this week, so I am in a bit degraded mode. > > For reference, locking fix below. > > > > From: Jiri Kosina <jkosina@suse.cz> > Subject: [PATCH] HID: protect hid_debug_list > > Accesses to hid_device->hid_debug_list are not serialized properly, which > could result in SMP concurrency issues when HID debugfs events are accessesed s/accessesed/accessed ? > by multiple userspace processess. s/processess/processes ? > > Serialize all the list operations by a mutex. > > Reported-by: Al Viro <viro@zeniv.linux.org.uk> > Signed-off-by: Jiri Kosina <jkosina@suse.cz> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> I also have a patch regarding forcing hidraw output even if raw_event returns > 0, but I'll send it over a new thread. This thread will start to be quite complicate to follow otherwise... :) Cheers, Benjamin -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 1129f49..e3b7123 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2347,6 +2347,7 @@ struct hid_device *hid_allocate_device(void) init_waitqueue_head(&hdev->debug_wait); INIT_LIST_HEAD(&hdev->debug_list); + mutex_init(&hdev->debug_list_lock); sema_init(&hdev->driver_lock, 1); sema_init(&hdev->driver_input_lock, 1); diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c index 933fff0..3337261 100644 --- a/drivers/hid/hid-debug.c +++ b/drivers/hid/hid-debug.c @@ -580,12 +580,14 @@ void hid_debug_event(struct hid_device *hdev, char *buf) int i; struct hid_debug_list *list; + mutex_lock(&hdev->debug_list_lock); list_for_each_entry(list, &hdev->debug_list, node) { for (i = 0; i < strlen(buf); i++) list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] = buf[i]; list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE; } + mutex_unlock(&hdev->debug_list_lock); wake_up_interruptible(&hdev->debug_wait); } @@ -960,7 +962,9 @@ static int hid_debug_events_open(struct inode *inode, struct file *file) file->private_data = list; mutex_init(&list->read_mutex); + mutex_lock(&list->hdev->debug_list_lock); list_add_tail(&list->node, &list->hdev->debug_list); + mutex_unlock(&list->hdev->debug_list_lock); out: return err; @@ -1055,7 +1059,9 @@ static int hid_debug_events_release(struct inode *inode, struct file *file) { struct hid_debug_list *list = file->private_data; + mutex_lock(&list->hdev->debug_list_lock); list_del(&list->node); + mutex_unlock(&list->hdev->debug_list_lock); kfree(list->hid_debug_buf); kfree(list); diff --git a/include/linux/hid.h b/include/linux/hid.h index b7b5ff2..af1b86d 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -515,6 +515,7 @@ struct hid_device { /* device report descriptor */ struct dentry *debug_rdesc; struct dentry *debug_events; struct list_head debug_list; + struct mutex debug_list_lock; wait_queue_head_t debug_wait; };