Re: [PATCH for-next v2] RDMA/cma: Replace RMW with atomic bit-ops

[Haakon Bugge <haakon.bugge@oracle.com>]

> On 21 Jun 2021, at 09:10, Leon Romanovsky <leon@kernel.org> wrote:
> 
> On Thu, Jun 17, 2021 at 02:59:25PM +0200, Håkon Bugge wrote:
>> The struct rdma_id_private contains three bit-fields, tos_set,
>> timeout_set, and min_rnr_timer_set. These are set by accessor
>> functions without any synchronization. If two or all accessor
>> functions are invoked in close proximity in time, there will be
>> Read-Modify-Write from several contexts to the same variable, and the
>> result will be intermittent.
>> 
>> Replace with a flag variable and an inline function for set with
>> appropriate memory barriers and the use of test_bit().
>> 
>> Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
>> Signed-off-by: Hans Westgaard Ry<hans.westgaard.ry@oracle.com>
>> 
>> ---
>> 	v1 -> v2:
>> 	   * Removed define wizardry and replaced with a set function
>>             with memory barriers. Suggested by Leon.
>> 	   * Removed zero-initialization of flags, due to kzalloc(),
>>             as suggested by Leon
>> 	   * Review comments from Stefan implicitly adapted due to
>>             first bullet above
>> 	   * Moved defines and inline function from header file to
>>             cma.c, as suggested by the undersigned
>> 	   * Renamed enum to cm_id_priv_flag_bits as suggested by the
>>             undersigned
>> ---
>> drivers/infiniband/core/cma.c      | 38 +++++++++++++++++++++++++-------------
>> drivers/infiniband/core/cma_priv.h |  4 +---
>> 2 files changed, 26 insertions(+), 16 deletions(-)
> 
> This patch generates checkpatch warnings.
> 
> ➜  kernel git:(rdma-next) git checkpatch
> WARNING: line length of 86 exceeds 80 columns
> #69: FILE: drivers/infiniband/core/cma.c:1149:
> +	if ((*qp_attr_mask & IB_QP_TIMEOUT) && test_bit(TIMEOUT_SET, &id_priv->flags))
> 
> WARNING: line length of 98 exceeds 80 columns
> #73: FILE: drivers/infiniband/core/cma.c:1152:
> +	if ((*qp_attr_mask & IB_QP_MIN_RNR_TIMER) && test_bit(MIN_RNR_TIMER_SET, &id_priv->flags))
> 
> WARNING: line length of 86 exceeds 80 columns
> #127: FILE: drivers/infiniband/core/cma.c:3048:
> +	u8 tos = test_bit(TOS_SET, &id_priv->flags) ? id_priv->tos : default_roce_tos;
> 
> WARNING: line length of 84 exceeds 80 columns
> #136: FILE: drivers/infiniband/core/cma.c:3096:
> +	route->path_rec->packet_life_time = test_bit(TIMEOUT_SET, &id_priv->flags) ?
> 
> 0001-RDMA-cma-Replace-RMW-with-atomic-bit-ops.patch total: 0 errors, 4 warnings, 118 lines checked

You're running an old checkpatch. Since commit bdc48fa11e46 ("checkpatch/coding-style: deprecate 80-column warning"), the default line-length is 100. As Linus states in:

https://lkml.org/lkml/2009/12/17/229

"... But 80 characters is causing too many idiotic changes."

So, indeed, the commit passes:

$ scripts/checkpatch.pl --strict --git HEAD
total: 0 errors, 0 warnings, 0 checks, 118 lines checked

Commit d4d0dcd9513e ("RDMA/cma: Replace RMW with atomic bit-ops") has no obvious style problems and is ready for submission.



Thxs, Håkon



> 
> Thanks