1. 20 Apr, 2016 2 commits
    • Mauro Carvalho Chehab's avatar
      [media] media: Improve documentation for link_setup/link_modify · 5ed470fe
      Mauro Carvalho Chehab authored
      Those callbacks are called with the media_device.graph_mutex held.
      
      Add a note about that, as the code called by those notifiers should
      not be touching in the mutex.
      Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
      Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
      Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
      5ed470fe
    • Mauro Carvalho Chehab's avatar
      [media] media-device: get rid of the spinlock · e2c91d4d
      Mauro Carvalho Chehab authored
      Right now, the lock schema for media_device struct is messy,
      since sometimes, it is protected via a spin lock, while, for
      media graph traversal, it is protected by a mutex.
      
      Solve this conflict by always using a mutex.
      
      As a side effect, this prevents a bug when the media notifiers
      is called at atomic context, while running the notifier callback:
      
       BUG: sleeping function called from invalid context at mm/slub.c:1289
       in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe
       4 locks held by modprobe/3479:
       #0:  (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160
       #1:  (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160
       #2:  (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio]
       #3:  (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media]
       CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49
       Hardware name:                  /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015
       0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000
       ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000
       ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5
       Call Trace:
       [<ffffffff81933901>] dump_stack+0x85/0xc4
       [<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0
       [<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0
       [<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300
       [<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media]
       [<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media]
       [<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media]
       [<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828]
       [<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media]
       [<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media]
      Reviewed-by: default avatarJavier Martinez Canillas <javier@osg.samsung.com>
      Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
      Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
      Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
      e2c91d4d
  2. 13 Apr, 2016 38 commits