From: Jason Gunthorpe <jgg@ziepe.ca>
To: Zhu Yanjun <yanjun.zhu@intel.com>
Cc: zyjzyj2000@gmail.com, leon@kernel.org,
linux-rdma@vger.kernel.org, Zhu Yanjun <yanjun.zhu@linux.dev>
Subject: Re: [for-next PATCH 1/1] RDMA/rxe: sgt_append from ib_umem_get is not highmem
Date: Mon, 21 Nov 2022 11:28:49 -0400 [thread overview]
Message-ID: <Y3uZMQJgcNFDhq5L@ziepe.ca> (raw)
In-Reply-To: <20221120012939.539953-1-yanjun.zhu@intel.com>
On Sat, Nov 19, 2022 at 08:29:38PM -0500, Zhu Yanjun wrote:
> From: Zhu Yanjun <yanjun.zhu@linux.dev>
>
> In ib_umem_get, sgt_append is allocated from the function
> sg_alloc_append_table_from_pages. And it is not from highmem.
You've confused the allocation of the SGL table itself with the
page_address called on the struct page * stored inside the SGL table.
Think of the SGL as an array of 'struct page *'
The page_address() can return NULL because the 'struct page *' it
contains came from userspace and could very will be highmem.
Jason
next prev parent reply other threads:[~2022-11-21 15:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-30 3:04 [PATCH for-next v2] RDMA/rxe: Fix mr->map double free Li Zhijian
2022-11-12 3:29 ` lizhijian
2022-11-13 12:40 ` Yanjun Zhu
2022-11-16 0:10 ` Yanjun Zhu
2022-11-16 2:39 ` lizhijian
2022-11-19 0:15 ` Jason Gunthorpe
2022-11-19 8:25 ` Yanjun Zhu
2022-11-20 1:29 ` [for-next PATCH 1/1] RDMA/rxe: sgt_append from ib_umem_get is not highmem Zhu Yanjun
2022-11-19 10:30 ` lizhijian
2022-11-19 13:20 ` Yanjun Zhu
2022-11-21 15:28 ` Jason Gunthorpe [this message]
2022-11-22 4:07 ` Yanjun Zhu
2022-11-22 14:06 ` Jason Gunthorpe
2022-11-23 1:53 ` Yanjun Zhu
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