From: Al Viro <viro@ZenIV.linux.org.uk>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: v9fs-developer@lists.sourceforge.net, ericvh@gmail.com,
rminnich@sandia.gov, lucho@ionkov.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/5] 9p: introduce async read requests
Date: Sat, 10 Dec 2016 01:50:59 +0000 [thread overview]
Message-ID: <20161210015059.GD1555@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1481230746-16741-4-git-send-email-sstabellini@kernel.org>
On Thu, Dec 08, 2016 at 12:59:05PM -0800, Stefano Stabellini wrote:
> + } else {
> + req = p9_client_get_req(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize);
> + if (IS_ERR(req)) {
> + *err = PTR_ERR(req);
> + break;
> + }
> + req->rsize = iov_iter_get_pages_alloc(to, &req->pagevec,
> + (size_t)rsize, &req->offset);
> + req->kiocb = iocb;
> + for (i = 0; i < req->rsize; i += PAGE_SIZE)
> + page_cache_get_speculative(req->pagevec[i/PAGE_SIZE]);
> + req->callback = p9_client_read_complete;
> +
> + *err = clnt->trans_mod->request(clnt, req);
> + if (*err < 0) {
> + clnt->status = Disconnected;
> + release_pages(req->pagevec,
> + (req->rsize + PAGE_SIZE - 1) / PAGE_SIZE,
> + true);
> + kvfree(req->pagevec);
> + p9_free_req(clnt, req);
> + break;
> + }
> +
> + *err = -EIOCBQUEUED;
IDGI. AFAICS, your code will result in shitloads of short reads - every
time when you give it a multi-iovec array, only the first one will be
issued and the rest won't be even looked at. Sure, it is technically
legal, but I very much doubt that aio users will be happy with that.
What am I missing here?
next prev parent reply other threads:[~2016-12-10 1:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 20:58 [PATCH 0/5] async requests support for 9pfs Stefano Stabellini
2016-12-08 20:59 ` [PATCH 1/5] 9p: add iocb parameter to p9_client_read and p9_client_write Stefano Stabellini
2016-12-08 20:59 ` [PATCH 2/5] 9p: store req details and callback in struct p9_req_t Stefano Stabellini
2016-12-09 7:18 ` [V9fs-developer] " Dominique Martinet
2016-12-09 23:24 ` Stefano Stabellini
2016-12-08 20:59 ` [PATCH 3/5] 9p: introduce p9_client_get_req Stefano Stabellini
2016-12-08 20:59 ` [PATCH 4/5] 9p: introduce async read requests Stefano Stabellini
2016-12-09 7:27 ` [V9fs-developer] " Dominique Martinet
2016-12-09 22:22 ` Stefano Stabellini
2016-12-10 1:50 ` Al Viro [this message]
2016-12-13 1:15 ` Stefano Stabellini
2016-12-13 14:29 ` Latchesar Ionkov
2016-12-08 20:59 ` [PATCH 5/5] 9p: introduce async write requests Stefano Stabellini
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