From: Chuck Lever <cel@citi.umich.edu>
To: Andrew Morton <akpm@osdl.org>
Cc: cel@netapp.com, linux-kernel@vger.kernel.org, trond.myklebust@fys.uio.no
Subject: Re: [PATCH 5/6] nfs: check all iov segments for correct memory access rights
Date: Fri, 19 May 2006 15:36:45 -0400 [thread overview]
Message-ID: <446E1E4D.7050800@citi.umich.edu> (raw)
In-Reply-To: <20060519112231.5ed3d565.akpm@osdl.org>
Andrew Morton wrote:
>> + if (unlikely(!access_ok(type, buf, len))) {
>> + retval = -EFAULT;
>> + goto out;
>> + }
>
> Now what's up here? Why does NFS, at this level, care about the page's
> virtual address? get_user_pages() will handle that?
I guess I'm not clear on what behavior is desired for scatter/gather if
one of the segments in an iov fails.
If one of the iov's will cause an EFAULT, how is that reported back to
the application, and what happens to the I/O being requested in the
other segments of the vector? When do we use an "all or nothing"
semantic, and when is it OK for some segments to fail?
--
corporate: cel at netapp dot com
personal: chucklever at bigfoot dot com
next prev parent reply other threads:[~2006-05-19 19:36 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-19 17:56 [PATCH 0/6] Support scatter/gather I/O in NFS direct I/O path Chuck Lever
2006-05-19 18:00 ` [PATCH 1/6] nfs: "open code" the NFS direct write rescheduler Chuck Lever
2006-05-19 18:10 ` Andrew Morton
2006-05-19 18:37 ` Chuck Lever
2006-05-19 18:46 ` Andrew Morton
2006-05-19 18:56 ` Chuck Lever
2006-05-19 18:00 ` [PATCH 2/6] nfs: remove user_addr and user_count from nfs_direct_req Chuck Lever
2006-05-19 18:00 ` [PATCH 3/6] nfs: Eliminate nfs_get_user_pages() Chuck Lever
2006-05-19 18:17 ` Andrew Morton
2006-05-19 19:18 ` Chuck Lever
2006-05-19 18:00 ` [PATCH 4/6] nfs: alloc nfs_read/write_data as direct I/O is scheduled Chuck Lever
2006-05-19 18:00 ` [PATCH 5/6] nfs: check all iov segments for correct memory access rights Chuck Lever
2006-05-19 18:22 ` Andrew Morton
2006-05-19 18:46 ` Chuck Lever
2006-05-19 19:36 ` Chuck Lever [this message]
2006-05-19 20:07 ` Andrew Morton
2006-05-19 18:25 ` Badari Pulavarty
2006-05-22 11:27 ` Andi Kleen
2006-05-19 18:00 ` [PATCH 6/6] nfs: Support vector I/O throughout the NFS direct I/O path Chuck Lever
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