From: Jens Axboe <axboe@kernel.dk>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] eventfd: convert to f_op->read_iter()
Date: Fri, 1 May 2020 11:49:07 -0600 [thread overview]
Message-ID: <2fa3e8dc-172e-2ac6-bc5e-a8fea5491e22@kernel.dk> (raw)
In-Reply-To: <20200501174306.GM23230@ZenIV.linux.org.uk>
On 5/1/20 11:43 AM, Al Viro wrote:
> On Fri, May 01, 2020 at 11:18:05AM -0600, Jens Axboe wrote:
>
>> - if (res > 0 && put_user(ucnt, (__u64 __user *)buf))
>> + if (res > 0 && copy_to_iter(&ucnt, res, iov) < res)
>
> *whoa*
>
> It is correct, but only because here res > 0 <=> res == 8.
> And that's not trivial at the first glance.
>
> Please, turn that into something like
Looks good to me, just one minor edit:
> if (iov_iter_count(to) < sizeof(ucnt))
> return -EINVAL;
> spin_lock_irq(&ctx->wqh.lock);
> if (!ctx->count) {
> if (unlikely(file->f_flags & O_NONBLOCK) {
> spin_unlock_irq(&ctx->wqh.lock)
> return -EAGAIN;
> }
> __add_wait_queue(&ctx->wqh, &wait);
> for (;;) {
> set_current_state(TASK_INTERRUPTIBLE);
> if (ctx->count)
> break;
> if (signal_pending(current)) {
> spin_unlock_irq(&ctx->wqh.lock)
> return -ERESTARTSYS;
> }
We need to remove waitq and re-set task state here. I'll run a sanity
check on that and send out a v3.
--
Jens Axboe
prev parent reply other threads:[~2020-05-01 17:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 17:18 [PATCH v2] eventfd: convert to f_op->read_iter() Jens Axboe
2020-05-01 17:43 ` Al Viro
2020-05-01 17:49 ` Jens Axboe [this message]
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=2fa3e8dc-172e-2ac6-bc5e-a8fea5491e22@kernel.dk \
--to=axboe@kernel.dk \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/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).