Struct API changed after upgrade kernel to 4.1.3 - linux-kernel

Question

struct net_device has no member named pm_qos_req.
Where can I find the relevant API structure?

Answer 1

SHORT ANSWER
pm_qos_req field in struct net_device was using only for e1000e driver, therefore it was decided to move this field to e1000e driver structure, so that rest of drivers that use struct net_device will not waste a few bytes of memory when allocating struct net_device. See e2c6544829 commit for details.
If you are developing e1000e driver and having issues, you can back-port e2c6544829 commit to your kernel baseline.
Otherwise, if you are maintaining some driver which is not upstreamed and is using pm_qos_req, use e2c6544829 commit as reference to rework your driver. Basically you need to add pm_qos_req field to your driver struct and use it from that struct instead of struct net_device.
THE WHOLE INVESTIGATION
Here is how you can figure this out:
Download mainline kernel:
$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Checkout to corresponding tag (well, in your case you can skip this step):
$ git checkout v4.1-rc3
(v4.1-rc3 is a tag; all tags can be listed by git tag command)
Search for pm_qos_req text changed in include/linux/netdevice.h file, using git:
$ git log -S'pm_qos_req' --oneline -- include/linux/netdevice.h
It will give you next commits:
01d460d net: Remove remaining remnants of pm_qos from netdevice.h
e2c6544 e1000e: Move pm_qos_req to e1000e adapter
536721b net: kernel-doc compliant documentation for net_device
ed77134 PM QOS update
Top commit in that list is the last one (was added most recently).
Check out interested commits with git show command. You are particularly interested in e2c6544 commit (it's where .pm_qos_req was removed from struct net_device):
$ git show e2c6544
Pay attention to commit message:
e1000e is the only driver requiring pm_qos_req, instead of causing
every device to waste up to 240 bytes. Allocate it for the specific
driver.
Now we can checkout to previous kernel versions and check which drivers are using this pm_qos_req field.
$ git grep -n '\bpm_qos_req\b' v3.0 -- drivers/
From grep output we can see that only e1000e driver is using this field.