From: Steve Wise <swise@opengridcomputing.com>
To: Jason Gunthorpe <jgg@ziepe.ca>, Nicholas Mc Guire <hofrat@osadl.org>
Cc: Doug Ledford <dledford@redhat.com>,
Raju Rangoju <rajur@chelsio.com>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] iw_cxgb4: drop check - dead code
Date: Wed, 23 Jan 2019 12:45:11 -0600 [thread overview]
Message-ID: <91af1982-e309-476e-cfa4-2f6ef1ee598b@opengridcomputing.com> (raw)
In-Reply-To: <20190123183008.GA15698@ziepe.ca>
On 1/23/2019 12:30 PM, Jason Gunthorpe wrote:
> On Sun, Jan 20, 2019 at 02:27:13AM +0100, Nicholas Mc Guire wrote:
>> The kmalloc is called with | __GFP_NOFAIL so there is no point in
>> checking the return value - it either returns valid storage or it would
>> hang/terminate there. But it is not possible to say if the use of
>> __GFP_NOFAIL is really needed and the check should be removed or
>> vice-versa (use of __GFP_NOFAIL should be only in exceptional
>> cases as I understand it and alloc_srq_queue() is called in quite
>> a few places)
>> In either way it would need fixing.
>>
>> Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
>> Fixes: 6a0b6174d35a ("rdma/cxgb4: Add support for kernel mode SRQ's")
>> ---
>
> Steve? It seems weird to have NOFAIL and then have an error unwind
> path, what is the deal here?
>
>> diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
>> index 917ce5c..c2a12ba 100644
>> --- a/drivers/infiniband/hw/cxgb4/qp.c
>> +++ b/drivers/infiniband/hw/cxgb4/qp.c
>> @@ -2597,8 +2597,6 @@ static int alloc_srq_queue(struct c4iw_srq *srq, struct c4iw_dev_ucontext *uctx,
>> wr_len = sizeof(*res_wr) + sizeof(*res);
>>
>> skb = alloc_skb(wr_len, GFP_KERNEL | __GFP_NOFAIL);
>> - if (!skb)
>> - goto err_free_queue;
>> set_wr_txq(skb, CPL_PRIORITY_CONTROL, 0);
>>
>> res_wr = (struct fw_ri_res_wr *)__skb_put(skb, wr_len);
>> --
>> 2.1.4
>>
The other queue allocations in qp.c don't use __GFP_NOFAIL. So either
leave it and remove the error check as per this patch, or remove the
NOFAIL and leave the check.
I suggest you remove the __GFP_NOFAIL, since I have a recollection that
using it was frowned upon. In this case, if there is no memory
available it is reasonable to return that error to the user creating the
srq...
Steve.
next prev parent reply other threads:[~2019-01-23 18:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-20 1:27 [PATCH RFC] iw_cxgb4: drop check - dead code Nicholas Mc Guire
2019-01-21 2:05 ` Jason Gunthorpe
2019-01-23 18:30 ` Jason Gunthorpe
2019-01-23 18:43 ` Steve Wise
2019-01-23 18:45 ` Steve Wise [this message]
2019-01-24 1:53 ` Nicholas Mc Guire
2019-01-23 21:44 ` Jason Gunthorpe
2019-01-23 21:48 ` Steve Wise
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=91af1982-e309-476e-cfa4-2f6ef1ee598b@opengridcomputing.com \
--to=swise@opengridcomputing.com \
--cc=dledford@redhat.com \
--cc=hofrat@osadl.org \
--cc=jgg@ziepe.ca \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=rajur@chelsio.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox