From: Jason Gunthorpe <jgg@ziepe.ca>
To: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
"David S. Miller" <davem@davemloft.net>,
Nicholas Piggin <npiggin@gmail.com>,
Khalid Aziz <khalid.aziz@oracle.com>,
Andrey Konovalov <andreyknvl@google.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
linux-mips@vger.kernel.org, linux-sh@vger.kernel.org,
sparclinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/16] mm: use untagged_addr() for get_user_pages_fast addresses
Date: Fri, 21 Jun 2019 10:39:11 -0300 [thread overview]
Message-ID: <20190621133911.GL19891@ziepe.ca> (raw)
In-Reply-To: <20190611144102.8848-2-hch@lst.de>
On Tue, Jun 11, 2019 at 04:40:47PM +0200, Christoph Hellwig wrote:
> This will allow sparc64 to override its ADI tags for
> get_user_pages and get_user_pages_fast.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> mm/gup.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index ddde097cf9e4..6bb521db67ec 100644
> +++ b/mm/gup.c
> @@ -2146,7 +2146,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
> unsigned long flags;
> int nr = 0;
>
> - start &= PAGE_MASK;
> + start = untagged_addr(start) & PAGE_MASK;
> len = (unsigned long) nr_pages << PAGE_SHIFT;
> end = start + len;
Hmm, this function, and the other, goes on to do:
if (unlikely(!access_ok((void __user *)start, len)))
return 0;
and I thought that access_ok takes in the tagged pointer?
How about re-order it a bit?
diff --git a/mm/gup.c b/mm/gup.c
index ddde097cf9e410..f48747ced4723b 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2148,11 +2148,12 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
start &= PAGE_MASK;
len = (unsigned long) nr_pages << PAGE_SHIFT;
- end = start + len;
-
if (unlikely(!access_ok((void __user *)start, len)))
return 0;
+ start = untagged_ptr(start);
+ end = start + len;
+
/*
* Disable interrupts. We use the nested form as we can already have
* interrupts disabled by get_futex_key.
next prev parent reply other threads:[~2019-06-21 13:39 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-11 14:40 switch the remaining architectures to use generic GUP v3 Christoph Hellwig
2019-06-11 14:40 ` [PATCH 01/16] mm: use untagged_addr() for get_user_pages_fast addresses Christoph Hellwig
2019-06-11 19:22 ` Khalid Aziz
2019-06-21 13:16 ` Jason Gunthorpe
2019-06-21 13:39 ` Jason Gunthorpe [this message]
2019-06-21 15:35 ` Khalid Aziz
2019-06-21 15:54 ` Jason Gunthorpe
2019-06-25 7:41 ` Christoph Hellwig
2019-06-25 7:43 ` Christoph Hellwig
2019-06-11 14:40 ` [PATCH 02/16] mm: simplify gup_fast_permitted Christoph Hellwig
2019-06-21 13:40 ` Jason Gunthorpe
2019-06-11 14:40 ` [PATCH 03/16] mm: lift the x86_32 PAE version of gup_get_pte to common code Christoph Hellwig
2019-06-21 13:45 ` Jason Gunthorpe
2019-06-11 14:40 ` [PATCH 04/16] MIPS: use the generic get_user_pages_fast code Christoph Hellwig
2019-06-21 14:05 ` Jason Gunthorpe
2019-06-25 7:46 ` Christoph Hellwig
2019-06-11 14:40 ` [PATCH 05/16] sh: add the missing pud_page definition Christoph Hellwig
2019-06-11 14:40 ` [PATCH 06/16] sh: use the generic get_user_pages_fast code Christoph Hellwig
2019-06-11 14:40 ` [PATCH 07/16] sparc64: add the missing pgd_page definition Christoph Hellwig
2019-06-11 14:40 ` [PATCH 08/16] sparc64: define untagged_addr() Christoph Hellwig
2019-06-11 19:23 ` Khalid Aziz
2019-06-11 14:40 ` [PATCH 09/16] sparc64: use the generic get_user_pages_fast code Christoph Hellwig
2019-06-11 19:35 ` Khalid Aziz
2019-06-11 14:40 ` [PATCH 10/16] mm: rename CONFIG_HAVE_GENERIC_GUP to CONFIG_HAVE_FAST_GUP Christoph Hellwig
2019-06-11 19:35 ` Khalid Aziz
2019-06-21 14:28 ` Jason Gunthorpe
2019-06-25 7:50 ` Christoph Hellwig
2019-06-11 14:40 ` [PATCH 11/16] mm: consolidate the get_user_pages* implementations Christoph Hellwig
2019-06-21 14:41 ` Jason Gunthorpe
2019-06-25 7:56 ` Christoph Hellwig
2019-06-25 11:56 ` Jason Gunthorpe
2019-06-11 14:40 ` [PATCH 12/16] mm: validate get_user_pages_fast flags Christoph Hellwig
2019-06-11 14:40 ` [PATCH 13/16] mm: move the powerpc hugepd code to mm/gup.c Christoph Hellwig
2019-06-11 14:41 ` [PATCH 14/16] mm: switch gup_hugepte to use try_get_compound_head Christoph Hellwig
2019-06-11 14:41 ` [PATCH 15/16] mm: mark the page referenced in gup_hugepte Christoph Hellwig
2019-06-11 14:41 ` [PATCH 16/16] mm: pass get_user_pages_fast iterator arguments in a structure Christoph Hellwig
2019-06-12 0:52 ` Nicholas Piggin
2019-06-12 1:09 ` Linus Torvalds
2019-06-20 12:18 ` Nicholas Piggin
2019-06-20 17:21 ` Linus Torvalds
2019-06-21 8:15 ` Christoph Hellwig
2019-06-21 23:55 ` Nicholas Piggin
2019-06-21 8:29 ` Nicholas Piggin
2019-06-12 1:27 ` Nadav Amit
2019-06-20 11:45 ` switch the remaining architectures to use generic GUP v3 Christoph Hellwig
2019-06-21 14:43 ` Jason Gunthorpe
2019-06-25 14:36 switch the remaining architectures to use generic GUP v4 Christoph Hellwig
2019-06-25 14:37 ` [PATCH 01/16] mm: use untagged_addr() for get_user_pages_fast addresses Christoph Hellwig
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