From: Mikulas Patocka <mpatocka@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Eric Sandeen <esandeen@redhat.com>,
Dave Chinner <dchinner@redhat.com>,
"Kani, Toshi" <toshi.kani@hpe.com>,
"Norton, Scott J" <scott.norton@hpe.com>,
"Tadakamadla,
Rajesh (DCIG/CDI/HPS Perf)" <rajesh.tadakamadla@hpe.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: [PATCH] pmem: fix __copy_user_flushcache
Date: Wed, 16 Sep 2020 14:56:38 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.02.2009161451140.21915@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <CAPcyv4gD0ZFkfajKTDnJhEEjf+5Av-GH+cHRFoyhzGe8bNEgAA@mail.gmail.com>
On Wed, 16 Sep 2020, Dan Williams wrote:
> On Wed, Sep 16, 2020 at 10:24 AM Mikulas Patocka <mpatocka@redhat.com> wrote:
> >
> >
> >
> > On Wed, 16 Sep 2020, Dan Williams wrote:
> >
> > > On Wed, Sep 16, 2020 at 3:57 AM Mikulas Patocka <mpatocka@redhat.com> wrote:
> > > >
> > > >
> > > >
> > > > I'm submitting this patch that adds the required exports (so that we could
> > > > use __copy_from_user_flushcache on x86, arm64 and powerpc). Please, queue
> > > > it for the next merge window.
> > >
> > > Why? This should go with the first user, and it's not clear that it
> > > needs to be relative to the current dax_operations export scheme.
> >
> > Before nvfs gets included in the kernel, I need to distribute it as a
> > module. So, it would make my maintenance easier. But if you don't want to
> > export it now, no problem, I can just copy __copy_user_flushcache from the
> > kernel to the module.
>
> That sounds a better plan than exporting symbols with no in-kernel consumer.
BTW, this function is buggy. Here I'm submitting the patch.
From: Mikulas Patocka <mpatocka@redhat.com>
If we copy less than 8 bytes and if the destination crosses a cache line,
__copy_user_flushcache would invalidate only the first cache line. This
patch makes it invalidate the second cache line as well.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
---
arch/x86/lib/usercopy_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6/arch/x86/lib/usercopy_64.c
===================================================================
--- linux-2.6.orig/arch/x86/lib/usercopy_64.c 2020-09-05 10:01:27.000000000 +0200
+++ linux-2.6/arch/x86/lib/usercopy_64.c 2020-09-16 20:48:31.000000000 +0200
@@ -120,7 +120,7 @@ long __copy_user_flushcache(void *dst, c
*/
if (size < 8) {
if (!IS_ALIGNED(dest, 4) || size != 4)
- clean_cache_range(dst, 1);
+ clean_cache_range(dst, size);
} else {
if (!IS_ALIGNED(dest, 8)) {
dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
next prev parent reply other threads:[~2020-09-16 18:57 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 12:34 [RFC] nvfs: a filesystem for persistent memory Mikulas Patocka
2020-09-15 13:00 ` Matthew Wilcox
2020-09-15 13:24 ` Mikulas Patocka
2020-09-22 10:04 ` Ritesh Harjani
2020-09-15 15:16 ` Dan Williams
2020-09-15 16:58 ` Mikulas Patocka
2020-09-15 17:38 ` Mikulas Patocka
2020-09-16 10:57 ` [PATCH] pmem: export the symbols __copy_user_flushcache and __copy_from_user_flushcache Mikulas Patocka
2020-09-16 16:21 ` Dan Williams
2020-09-16 17:24 ` Mikulas Patocka
2020-09-16 17:40 ` Dan Williams
2020-09-16 18:06 ` Mikulas Patocka
2020-09-21 16:20 ` NVFS XFS metadata (was: [PATCH] pmem: export the symbols __copy_user_flushcache and __copy_from_user_flushcache) Mikulas Patocka
2020-09-22 5:03 ` Dave Chinner
2020-09-22 16:46 ` Mikulas Patocka
2020-09-22 17:25 ` Matthew Wilcox
2020-09-24 15:00 ` Mikulas Patocka
2020-09-28 15:22 ` Mikulas Patocka
2020-09-23 2:45 ` Dave Chinner
2020-09-23 9:20 ` A bug in ext4 with big directories (was: NVFS XFS metadata) Mikulas Patocka
2020-09-23 9:44 ` Jan Kara
2020-09-23 12:46 ` Mikulas Patocka
2020-09-23 20:20 ` Andreas Dilger
2020-09-23 17:19 ` NVFS XFS metadata (was: [PATCH] pmem: export the symbols __copy_user_flushcache and __copy_from_user_flushcache) Mikulas Patocka
2020-09-23 9:57 ` Jan Kara
2020-09-23 13:11 ` Mikulas Patocka
2020-09-23 15:04 ` Matthew Wilcox
2020-09-22 12:28 ` Matthew Wilcox
2020-09-22 12:39 ` Mikulas Patocka
2020-09-16 18:56 ` Mikulas Patocka [this message]
2020-09-18 1:53 ` [PATCH] pmem: fix __copy_user_flushcache Dan Williams
2020-09-18 12:25 ` the "read" syscall sees partial effects of the "write" syscall Mikulas Patocka
2020-09-18 13:13 ` Jan Kara
2020-09-18 18:02 ` Linus Torvalds
2020-09-20 23:41 ` Dave Chinner
2020-09-17 6:50 ` [PATCH] pmem: export the symbols __copy_user_flushcache and __copy_from_user_flushcache Christoph Hellwig
2020-09-21 16:19 ` [RFC] nvfs: a filesystem for persistent memory Mikulas Patocka
2020-09-21 16:29 ` Dan Williams
2020-09-22 15:43 ` Ira Weiny
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