From: Jason Gunthorpe <jgg@nvidia.com>
To: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
David Hildenbrand <david@redhat.com>,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-perf-users@vger.kernel.org,
linux-security-module@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Eric Biederman <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
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Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
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Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Kentaro Takeda <takedakn@nttdata.co.jp>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Paul Moore <paul@paul-moore.com>,
James Morris <jmorris@namei.org>,
"Serge E . Hallyn" <serge@hallyn.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 3/7] mm/gup: remove vmas parameter from get_user_pages_remote()
Date: Mon, 17 Apr 2023 10:09:36 -0300 [thread overview]
Message-ID: <ZD1FECftWekha6Do@nvidia.com> (raw)
In-Reply-To: <5a4cf1ebf1c6cdfabbf2f5209facb0180dd20006.1681508038.git.lstoakes@gmail.com>
On Sat, Apr 15, 2023 at 12:27:31AM +0100, Lorenzo Stoakes wrote:
> The only instances of get_user_pages_remote() invocations which used the
> vmas parameter were for a single page which can instead simply look up the
> VMA directly. In particular:-
>
> - __update_ref_ctr() looked up the VMA but did nothing with it so we simply
> remove it.
>
> - __access_remote_vm() was already using vma_lookup() when the original
> lookup failed so by doing the lookup directly this also de-duplicates the
> code.
>
> This forms part of a broader set of patches intended to eliminate the vmas
> parameter altogether.
>
> Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
> ---
> arch/arm64/kernel/mte.c | 5 +++--
> arch/s390/kvm/interrupt.c | 2 +-
> fs/exec.c | 2 +-
> include/linux/mm.h | 2 +-
> kernel/events/uprobes.c | 10 +++++-----
> mm/gup.c | 12 ++++--------
> mm/memory.c | 9 +++++----
> mm/rmap.c | 2 +-
> security/tomoyo/domain.c | 2 +-
> virt/kvm/async_pf.c | 3 +--
> 10 files changed, 23 insertions(+), 26 deletions(-)
>
> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
> index f5bcb0dc6267..74d8d4007dec 100644
> --- a/arch/arm64/kernel/mte.c
> +++ b/arch/arm64/kernel/mte.c
> @@ -437,8 +437,9 @@ static int __access_remote_tags(struct mm_struct *mm, unsigned long addr,
> struct page *page = NULL;
>
> ret = get_user_pages_remote(mm, addr, 1, gup_flags, &page,
> - &vma, NULL);
> - if (ret <= 0)
> + NULL);
> + vma = vma_lookup(mm, addr);
> + if (ret <= 0 || !vma)
> break;
Given the slightly tricky error handling, it would make sense to turn
this pattern into a helper function:
page = get_single_user_page_locked(mm, addr, gup_flags, &vma);
if (IS_ERR(page))
[..]
static inline struct page *get_single_user_page_locked(struct mm_struct *mm,
unsigned long addr, int gup_flags, struct vm_area_struct **vma)
{
struct page *page;
int ret;
ret = get_user_pages_remote(*mm, addr, 1, gup_flags, &page, NULL, NULL);
if (ret < 0)
return ERR_PTR(ret);
if (WARN_ON(ret == 0))
return ERR_PTR(-EINVAL);
*vma = vma_lookup(mm, addr);
if (WARN_ON(!*vma) {
put_user_page(page);
return ERR_PTR(-EINVAL);
}
return page;
}
It could be its own patch so this change was just a mechanical removal
of NULL
Jason
next prev parent reply other threads:[~2023-04-17 13:09 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-14 23:25 [PATCH 0/7] remove the vmas parameter from GUP APIs Lorenzo Stoakes
2023-04-14 23:27 ` [PATCH 1/7] mm/gup: remove unused vmas parameter from get_user_pages() Lorenzo Stoakes
2023-04-15 5:27 ` Greg Kroah-Hartman
2023-04-17 13:01 ` Jason Gunthorpe
2023-04-14 23:27 ` [PATCH 2/7] mm/gup: remove unused vmas parameter from pin_user_pages_remote() Lorenzo Stoakes
2023-04-17 13:02 ` Jason Gunthorpe
2023-04-14 23:27 ` [PATCH 3/7] mm/gup: remove vmas parameter from get_user_pages_remote() Lorenzo Stoakes
2023-04-15 0:25 ` Tetsuo Handa
2023-04-15 8:11 ` Lorenzo Stoakes
2023-04-17 13:09 ` Jason Gunthorpe [this message]
2023-04-17 13:13 ` Lorenzo Stoakes
2023-04-17 13:16 ` Jason Gunthorpe
2023-04-17 13:23 ` Lorenzo Stoakes
2023-04-17 15:07 ` Eric W. Biederman
2023-04-17 15:14 ` Lorenzo Stoakes
2023-04-14 23:27 ` [PATCH 4/7] mm/gup: introduce the FOLL_SAME_FILE GUP flag Lorenzo Stoakes
2023-04-17 13:14 ` Jason Gunthorpe
2023-04-17 13:25 ` Lorenzo Stoakes
2023-04-17 13:27 ` Jason Gunthorpe
2023-04-14 23:27 ` [PATCH 5/7] io_uring: rsrc: use FOLL_SAME_FILE on pin_user_pages() Lorenzo Stoakes
2023-04-17 12:56 ` Jason Gunthorpe
2023-04-17 13:19 ` Lorenzo Stoakes
2023-04-17 13:26 ` Jason Gunthorpe
2023-04-17 14:00 ` Lorenzo Stoakes
2023-04-17 14:15 ` Jason Gunthorpe
2023-04-17 15:20 ` Lorenzo Stoakes
2023-04-17 19:00 ` Lorenzo Stoakes
2023-04-17 19:24 ` Jason Gunthorpe
2023-04-17 19:45 ` Lorenzo Stoakes
2023-04-18 16:25 ` Pavel Begunkov
2023-04-18 16:35 ` Pavel Begunkov
2023-04-18 16:36 ` Jason Gunthorpe
2023-04-18 17:25 ` Pavel Begunkov
2023-04-18 18:19 ` Jason Gunthorpe
2023-04-14 23:27 ` [PATCH 6/7] mm/gup: remove vmas parameter from pin_user_pages() Lorenzo Stoakes
2023-04-14 23:27 ` [PATCH 7/7] mm/gup: remove vmas array from internal GUP functions Lorenzo Stoakes
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