From: Arnd Bergmann <arnd@arndb.de>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-arch <linux-arch@vger.kernel.org>,
kexec@lists.infradead.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Eric Biederman <ebiederm@xmission.com>
Subject: Re: [PATCH 3/4] mm: remove compat_sys_move_pages
Date: Sat, 26 Sep 2020 17:21:29 +0200 [thread overview]
Message-ID: <CAK8P3a15GEGL8AnxTYZxD_EeGb7__v=iy6rTfCTNq2jmsQe9fQ@mail.gmail.com> (raw)
In-Reply-To: <20200919053807.GK30063@infradead.org>
On Sat, Sep 19, 2020 at 7:38 AM Christoph Hellwig <hch@infradead.org> wrote:
>
> I'd just keep the native version inline and have the compat one in
> a helper, but that is just a minor detail.
Folded in this change:
diff --git a/mm/migrate.c b/mm/migrate.c
index e9dfbde5f12c..d3fa3f4bf653 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1835,18 +1835,14 @@ static void do_pages_stat_array(struct
mm_struct *mm, unsigned long nr_pages,
mmap_read_unlock(mm);
}
-static int put_pages_array(const void __user *chunk_pages[],
- const void __user * __user *pages,
- unsigned long chunk_nr)
+static int put_compat_pages_array(const void __user *chunk_pages[],
+ const void __user * __user *pages,
+ unsigned long chunk_nr)
{
compat_uptr_t __user *pages32 = (compat_uptr_t __user *)pages;
compat_uptr_t p;
int i;
- if (!in_compat_syscall())
- return copy_from_user(chunk_pages, pages,
- chunk_nr * sizeof(*chunk_pages));
-
for (i = 0; i < chunk_nr; i++) {
if (get_user(p, pages32 + i))
return -EFAULT;
@@ -1875,8 +1871,15 @@ static int do_pages_stat(struct mm_struct *mm,
unsigned long nr_pages,
if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
chunk_nr = DO_PAGES_STAT_CHUNK_NR;
- if (put_pages_array(chunk_pages, pages, chunk_nr))
- break;
+ if (in_compat_syscall()) {
+ if (put_compat_pages_array(chunk_pages, pages,
+ chunk_nr))
+ break;
+ } else {
+ if (copy_from_user(chunk_pages, pages,
+ chunk_nr * sizeof(*chunk_pages)))
+ break;
+ }
do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);
It does make the separation cleaner but it's also more code, which is
why I had it in the combined function before.
Arnd
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next prev parent reply other threads:[~2020-09-26 15:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 13:24 [PATCH 0/4] syscalls: remove compat_alloc_user_space callers Arnd Bergmann
2020-09-18 13:24 ` [PATCH 1/4] x86: add __X32_COND_SYSCALL() macro Arnd Bergmann
2020-09-19 5:35 ` Christoph Hellwig
2020-09-19 16:23 ` Andy Lutomirski
2020-09-19 17:14 ` hpa
2020-09-19 17:39 ` Andy Lutomirski
2020-09-19 17:45 ` Brian Gerst
2020-09-18 13:24 ` [PATCH 2/4] kexec: remove compat_sys_kexec_load syscall Arnd Bergmann
2020-09-19 5:37 ` Christoph Hellwig
2020-09-26 21:10 ` Arnd Bergmann
2020-09-18 13:24 ` [PATCH 3/4] mm: remove compat_sys_move_pages Arnd Bergmann
2020-09-19 5:38 ` Christoph Hellwig
2020-09-26 15:21 ` Arnd Bergmann [this message]
2020-09-18 13:24 ` [PATCH 4/4] mm: remove compat numa syscalls Arnd Bergmann
2020-09-19 5:41 ` Christoph Hellwig
2020-09-26 15:14 ` Arnd Bergmann
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