From: Linus Torvalds <torvalds@linux-foundation.org>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
linuxppc-dev@lists.ozlabs.org,
linux-s390 <linux-s390@vger.kernel.org>
Subject: Re: Linux 5.1-rc5
Date: Tue, 16 Apr 2019 09:49:46 -0700 [thread overview]
Message-ID: <CAHk-=wj2SW0Zno0Yn=S9wrsmHOKV0FiFPiPS4TM=Gn8yjfYXAg@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=wjKi5C+Onhp5Vs5BQxHbaBud9M3cTS-S6Tr9yDY4dS-Sw@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 739 bytes --]
On Tue, Apr 16, 2019 at 9:16 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> We actually already *have* this function.
>
> It's called "gup_fast_permitted()" and it's used by x86-64 to verify
> the proper address range. Exactly like s390 needs..
>
> Could you please use that instead?
IOW, something like the attached.
Obviously untested. And maybe 'current' isn't declared in
<asm/pgtable.h>, in which case you'd need to modify it to instead make
the inline function be "s390_gup_fast_permitted()" that takes a
pointer to the mm, and do something like
#define gup_fast_permitted(start, pages) \
s390_gup_fast_permitted(current->mm, start, pages)
instead.
But I think you get the idea..
Linus
[-- Attachment #2: patch.diff --]
[-- Type: text/x-patch, Size: 724 bytes --]
arch/s390/include/asm/pgtable.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 76dc344edb8c..a08248995f50 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1659,4 +1659,16 @@ static inline void check_pgt_cache(void) { }
#include <asm-generic/pgtable.h>
+static inline bool gup_fast_permitted(unsigned long start, int nr_pages)
+{
+ unsigned long len, end;
+
+ len = (unsigned long)nr_pages << PAGE_SHIFT;
+ end = start + len;
+ if (end < start)
+ return false;
+ return end <= current->mm->context.asce_limit;
+}
+#define gup_fast_permitted gup_fast_permitted
+
#endif /* _S390_PAGE_H */
next prev parent reply other threads:[~2019-04-16 16:50 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-14 22:40 Linux 5.1-rc5 Linus Torvalds
2019-04-15 5:19 ` Christoph Hellwig
2019-04-15 16:17 ` Linus Torvalds
2019-04-16 9:09 ` Martin Schwidefsky
2019-04-16 12:06 ` Martin Schwidefsky
2019-04-16 16:16 ` Linus Torvalds
2019-04-16 16:49 ` Linus Torvalds [this message]
2019-04-17 7:46 ` Martin Schwidefsky
2019-04-17 8:02 ` Martin Schwidefsky
2019-04-17 16:57 ` Linus Torvalds
2019-04-18 8:02 ` Martin Schwidefsky
2019-04-18 15:49 ` Linus Torvalds
2019-04-18 18:41 ` Martin Schwidefsky
2019-04-19 13:33 ` Martin Schwidefsky
2019-04-19 17:27 ` Linus Torvalds
2019-04-23 15:38 ` Martin Schwidefsky
2019-04-23 16:06 ` Linus Torvalds
2019-04-17 3:38 ` Michael Ellerman
2019-04-17 4:13 ` Linus Torvalds
2019-05-02 12:21 ` Greg KH
2019-05-02 14:17 ` Martin Schwidefsky
2019-05-02 14:31 ` Greg KH
2019-05-02 15:10 ` Martin Schwidefsky
2019-05-20 11:09 ` Greg KH
2019-05-03 13:31 ` Michael Ellerman
2019-05-02 23:15 ` Christoph Hellwig
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