Bug 784959

Hi, could someone let me know what further info is needed from my side? Thanks!

(In reply to comment #0)
> Description of problem:
> 
> The rhel6_kabi_check script has reported 8 symbols not on the ABI whitelist. 
> We would like to make our kernel module ABI compatible.
> 
> Version-Release number of selected component (if applicable):
> 
> RHEL6.x (and RHEL5.x)
> 
> How reproducible:
> 
> 
> Steps to Reproduce:
> 1.
> 2.
> 3.
> 
> Actual results:
> 
> # ./rhel6_kabi_check-2.0.py -k 2.6.32-71.el6 -w
> /lib/modules/kabi/kabi_whitelist_x86_64 /usr/local/velobit/modules/velobit.ko
> Red Hat Enterprise Linux 6 ABI Checker
> --------------------------------------
> 
> ABI Checker version: 2.0
> 
> Module:    /usr/local/velobit/modules/velobit.ko
> Kernel:    2.6.32-71.el6.x86_64
> Whitelist: /lib/modules/kabi/kabi_whitelist_x86_64 (20100820-1.el6)
> 
> WARNING: The following symbols are used by your module
> WARNING: and are not on the ABI whitelist.
> 
> symbol: daemonize
> symbol: kernel_thread
> symbol: _read_trylock
> symbol: open_by_devnum
> symbol: bio_init
> symbol: blk_get_backing_dev_info
> symbol: getnstimeofday
> symbol: time_to_tm

To ask for KABI inclusion for any of the above below, I need to have
a reason - whats/why the usage in the module - for each symbol.

thanks

[Synopsis]
VeloBit HyerCache kernel module implements a disk device filter.  It hooks into a disk device request queue’s make_request_fn method.  It spawns multiple kernel threads to carry out its IO processing in various stages.

> symbol: daemonize
- Detach user resources from a newly created kernel thread.
> symbol: kernel_thread
- Create a kernel thread.
> symbol: _read_trylock
- Multiple readers attempt to acquire reader/writer type locks.
> symbol: open_by_devnum
- Gain access to a block device’s “struct block_device *” pointer.  The reason for accesing this pointer is to gain access to its “struct hd_struct *bd_part” and “struct gendisk *bd_disk” pointers.
- The reason for accessing the “struct hd_struct *bd_part” pointer is to gain access to various disk properties (such as start_sect, nr_sects, etc.).
- The reason for accessing the “struct gendisk *bd_disk” pointer is to gain access to its “make_request_fn” pointer for IO request redirections. 
> symbol: bio_init
- Initialize a “struct bio ” object.  In some cases VeloBit kernel module creates its own bio objects.
> symbol: blk_get_backing_dev_info
- Gain access to a block device’s backing device “struct backing_dev_info *” pointer.  The reason for accessing this pointer is to gain access to the “unplug_io_fn” method inside the structure.
> symbol: getnstimeofday
- Need this function for various performance measurements and function time statistics inside the VeloBit kernel module.
> symbol: time_to_tm
- For converting the Linux time to local time.  VeloBit kernel module uses this for its event logging.

I hope this is sufficient, but let me know if any further clarification is needed.  Thanks!

> 
> I hope this is sufficient, but let me know if any further clarification is
> needed.  Thanks!


I prepared patches and sent them for review

jirka

Thanks!

NACKed:

daemonize
kernel_thread
  reason: I think people are supposed to use kthread_create() these days, so NAK.

bio_init
  reason: I'd really like to know why they think they need to allocate their own
bios.  I'm pretty much against this one.

_read_trylock
  reason: rwlock_t is pretty much always wrong.

the rest of the symbols made it to the KABI.

For some reason those symbols went in under BZ 790418, so closing as duplicate.

*** This bug has been marked as a duplicate of bug 790418 ***

*** Bug 669795 has been marked as a duplicate of this bug. ***

Created attachment 1224307 [details]
ksc output containing the requested symbols

Created attachment 1238613 [details]
ksc output containing the requested symbols

Created attachment 1241746 [details]
ksc output containing the requested symbols