From: Al Viro <viro@zeniv.linux.org.uk>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Ira Weiny <ira.weiny@intel.com>
Subject: Re: [PATCH v3 4/4] fs/sysv: Replace kmap() with kmap_local_page()
Date: Fri, 20 Jan 2023 05:07:48 +0000 [thread overview]
Message-ID: <Y8ohpDtqI8bPAgRn@ZenIV> (raw)
In-Reply-To: <Y8oem+z9SN487MIm@casper.infradead.org>
On Fri, Jan 20, 2023 at 04:54:51AM +0000, Matthew Wilcox wrote:
> > Sure, but... there's also this:
> >
> > static inline void __kunmap_local(const void *addr)
> > {
> > #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
> > kunmap_flush_on_unmap(addr);
> > #endif
> > }
> >
> > Are you sure that the guts of that thing will be happy with address that is not
> > page-aligned? I've looked there at some point, got scared of parisc (IIRC)
> > MMU details and decided not to rely upon that...
>
> Ugh, PA-RISC (the only implementor) definitely will flush the wrong
> addresses. I think we should do this, as having bugs that only manifest
> on one not-well-tested architecture seems Bad.
>
> static inline void __kunmap_local(const void *addr)
> {
> #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
> - kunmap_flush_on_unmap(addr);
> + kunmap_flush_on_unmap(PAGE_ALIGN_DOWN(addr));
> #endif
> }
PTR_ALIGN_DOWN(addr, PAGE_SIZE), perhaps?
next prev parent reply other threads:[~2023-01-20 5:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-19 15:32 [PATCH v3 0/4] fs/sysv: Replace kmap() with kmap_local_page() Fabio M. De Francesco
2023-01-19 15:32 ` [PATCH v3 1/4] fs/sysv: Use the offset_in_page() helper Fabio M. De Francesco
2023-01-19 15:32 ` [PATCH v3 2/4] fs/sysv: Change the signature of dir_get_page() Fabio M. De Francesco
2023-01-19 15:32 ` [PATCH v3 3/4] fs/sysv: Use dir_put_page() in sysv_rename() Fabio M. De Francesco
2023-01-19 15:32 ` [PATCH v3 4/4] fs/sysv: Replace kmap() with kmap_local_page() Fabio M. De Francesco
2023-01-20 0:54 ` Al Viro
2023-01-20 4:21 ` Al Viro
2023-01-20 4:28 ` Matthew Wilcox
2023-01-20 4:45 ` Al Viro
2023-01-20 4:54 ` Matthew Wilcox
2023-01-20 5:07 ` Al Viro [this message]
2023-01-20 5:56 ` Al Viro
2023-01-20 7:17 ` Helge Deller
2023-01-21 8:05 ` Ira Weiny
2023-01-21 10:57 ` Helge Deller
2023-01-21 19:26 ` Al Viro
2023-01-23 17:14 ` Fabio M. De Francesco
2023-01-24 20:16 ` Ira Weiny
2023-01-23 17:03 ` Fabio M. De Francesco
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