From: Theodore Ts'o <tytso@mit.edu>
To: Tao Ma <tm@tao.ma>
Cc: kbuild test robot <fengguang.wu@intel.com>,
Tao Ma <boyu.mt@taobao.com>,
linux-ext4@vger.kernel.org
Subject: Re: [ext4:dev 37/63] fs/ext4/inline.c:268:19: error: 'empty_zero_page' undeclared
Date: Tue, 11 Dec 2012 00:12:05 -0500 [thread overview]
Message-ID: <20121211051205.GA23653@thunk.org> (raw)
In-Reply-To: <50C699A1.10502@tao.ma>
On Tue, Dec 11, 2012 at 10:25:37AM +0800, Tao Ma wrote:
> uh, in sparc, we don't have empty_zero_page? I just want to create an
> inline data file without allocating a buffer with the specified length.
> So maybe I have to do the kzalloc thing then. :(
Yeah, sparc64 apparently doesn't have empty_zero_page. All
architectures have ZERO_PAGE(0), which is what the DIO code uses, but
you can't count on it being mapped.
What we could do instead is pass in a value of "(void *) -1", and then
in ext4_xattr_set_entry(), if i->value is -1, use memset to zero out
the value instead of memcpy. This will be safe for all architectures,
since we already use casts of negative values for ERR_PTR.
In fact, we could just use "i.value = ERR_PTR(-1)" and
"IS_ERR_VALUE(i->value)", but it would be clearer to explicitly define
EXT4_ZERO_XATTR_VALUE to be "((void *) -1)", and use that to indicate
that ext4_xattr_set_entry() should zero out the page in question.
- Ted
next prev parent reply other threads:[~2012-12-11 5:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-10 22:02 [ext4:dev 37/63] fs/ext4/inline.c:268:19: error: 'empty_zero_page' undeclared kbuild test robot
2012-12-11 2:25 ` Tao Ma
2012-12-11 5:12 ` Theodore Ts'o [this message]
2012-12-11 5:17 ` Tao Ma
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20121211051205.GA23653@thunk.org \
--to=tytso@mit.edu \
--cc=boyu.mt@taobao.com \
--cc=fengguang.wu@intel.com \
--cc=linux-ext4@vger.kernel.org \
--cc=tm@tao.ma \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).