From: Jason Gunthorpe <jgg@ziepe.ca>
To: Leon Romanovsky <leon@kernel.org>
Cc: Junxian Huang <huangjunxian6@hisilicon.com>,
linux-rdma@vger.kernel.org, linuxarm@huawei.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 for-next 1/2] RDMA/core: Provide rdma_user_mmap_disassociate() to disassociate mmap pages
Date: Wed, 4 Sep 2024 13:04:58 -0300 [thread overview]
Message-ID: <20240904160458.GB1909087@ziepe.ca> (raw)
In-Reply-To: <20240903070922.GI4026@unreal>
On Tue, Sep 03, 2024 at 10:09:22AM +0300, Leon Romanovsky wrote:
> > The original thought was that ib_uverbs_mmap() reads ufile->disassociated while
> > uverbs_user_mmap_disassociate() writes it, and there might be a racing. We tried
> > to use atomic_t to avoid racing without adding locks.
>
> atomic_t is never a replacement for locks. It is a way to provide
> coherent view of the data between CPUs and makes sure that write/read is
> not interrupted.
Yes, add a lock, like I said
Jason
next prev parent reply other threads:[~2024-09-04 16:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-28 6:46 [PATCH v3 for-next 0/2] RDMA: Provide an API for drivers to disassociate mmap pages Junxian Huang
2024-08-28 6:46 ` [PATCH v3 for-next 1/2] RDMA/core: Provide rdma_user_mmap_disassociate() " Junxian Huang
2024-09-02 6:57 ` Leon Romanovsky
2024-09-02 13:32 ` Junxian Huang
2024-09-03 7:09 ` Leon Romanovsky
2024-09-04 16:04 ` Jason Gunthorpe [this message]
2024-08-28 6:46 ` [PATCH v3 for-next 2/2] RDMA/hns: Disassociate mmap pages for all uctx when HW is being reset Junxian Huang
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