From: Haakon Bugge <firstname.lastname@example.org> To: Leon Romanovsky <email@example.com> Cc: Doug Ledford <firstname.lastname@example.org>, Jason Gunthorpe <email@example.com>, Christian Benvenuti <firstname.lastname@example.org>, Dan Carpenter <email@example.com>, OFED mailing list <firstname.lastname@example.org>, Nelson Escobar <email@example.com> Subject: Re: [PATCH rdma-rc] RDMA/usnic: Lock VF with mutex instead of spinlock Date: Mon, 13 Sep 2021 12:50:58 +0000 [thread overview] Message-ID: <AC729233-CCB2-4A90-A7B2-08E534C3B1F1@oracle.com> (raw) In-Reply-To: <YT8LYZvhYm/kT7Kb@unreal> > On 13 Sep 2021, at 10:27, Leon Romanovsky <firstname.lastname@example.org> wrote: > > On Mon, Sep 13, 2021 at 08:17:00AM +0000, Haakon Bugge wrote: >> >> >>> On 13 Sep 2021, at 10:04, Leon Romanovsky <email@example.com> wrote: >>> >>> From: Leon Romanovsky <firstname.lastname@example.org> >>> >>> Usnic VF doesn't need lock in atomic context to create QPs, so it is safe >>> to use mutex instead of spinlock. Such change fixes the following smatch >>> error. >> >> s/GFP_ATOMIC/GFP_KERNEL/ in find_free_vf_and_create_qp_grp() as well? > > Do you mean in usnic_uiom_get_dev_list()? Sorry, my comments was v5.14.1 centric. For latest upstream, its alloc_res_chunk_list(), find_free_vf_and_create_qp_grp() -> usnic_ib_qp_grp_create -> alloc_res_chunk_list() > That GFP_ATOMIC existed before my patch while we are holding usdev_lock mutex. True. > Anyway, I prefer to touch that driver as less as possible. > > The allocations can continue to be with GFP_ATOMIC while we use mutex. > It is bad thing, but not a necessary to fix bug. We just wasting atomic > memory and instruct kernel do not sleep while > doing allocations. I assume this driver is not very much maintained by Cisco, hence, I agree with your rationale above, Reviewed-by: Håkon Bugge <email@example.com> Thxs, Håkon
next prev parent reply other threads:[~2021-09-13 12:51 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-13 8:04 Leon Romanovsky 2021-09-13 8:17 ` Haakon Bugge 2021-09-13 8:27 ` Leon Romanovsky 2021-09-13 12:50 ` Haakon Bugge [this message] 2021-09-23 5:34 ` Leon Romanovsky 2021-09-24 13:59 ` Jason Gunthorpe
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