[media] media: ti-vpe: vpdma: Fix race condition for firmware loading
authorNikhil Devshatwar <nikhil.nd@ti.com>
Fri, 18 Nov 2016 23:20:35 +0000 (21:20 -0200)
committerMauro Carvalho Chehab <mchehab@s-opensource.com>
Tue, 22 Nov 2016 10:07:28 +0000 (08:07 -0200)
commitc786595beb89d74ff709b2ee382f34a1e0040d88
treec6fb4a1e79b33c750f9e3f78b4b714df06f7eb66
parentdfe1349dc805aa3113e6fba9db55761d24ce63fe
[media] media: ti-vpe: vpdma: Fix race condition for firmware loading

vpdma_create API is supposed to allocated the struct vpdma_data and
return it to the driver. Also, it would call the callback function
when the VPDMA firmware is loaded.

Typically, VPE driver have following function call:
    dev->vpdma = vpdma_create(pdev, firmware_load_callback);
And the callback implementation would continue the probe further.
Also, the dev->vpdma is accessed from the callback implementation.

This may lead to race condition between assignment of dev->vpdma
and the callback function being triggered.
This would lead to kernel crash because of NULL pointer access.

Fix this by passing a driver wrapped &vpdma_data instead of allocating
inside vpdma_create.
Change the vpdma_create prototype accordingly and fix return paths.

Also, update the VPE driver to use the updated API and
initialize the dev->vpdma before hand so that the race condition
is avoided.

Signed-off-by: Nikhil Devshatwar <nikhil.nd@ti.com>
Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
drivers/media/platform/ti-vpe/vpdma.c
drivers/media/platform/ti-vpe/vpdma.h
drivers/media/platform/ti-vpe/vpe.c