linux-kernel - Re: [PATCH] dax: Fix missed PMD wakeups

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Message-ID: <20190711154111.GA29284@quack2.suse.cz>
Date:   Thu, 11 Jul 2019 17:41:11 +0200
From:   Jan Kara <jack@...e.cz>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     Jan Kara <jack@...e.cz>, Dan Williams <dan.j.williams@...el.com>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Boaz Harrosh <openosd@...il.com>,
        stable <stable@...r.kernel.org>,
        Robert Barror <robert.barror@...el.com>,
        Seema Pandit <seema.pandit@...el.com>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dax: Fix missed PMD wakeups

On Thu 11-07-19 08:25:50, Matthew Wilcox wrote:
> On Thu, Jul 11, 2019 at 07:13:50AM -0700, Matthew Wilcox wrote:
> > However, the XA_RETRY_ENTRY might be a good choice.  It doesn't normally
> > appear in an XArray (it may appear if you're looking at a deleted node,
> > but since we're holding the lock, we can't see deleted nodes).
> 
...

> @@ -254,7 +267,7 @@ static void wait_entry_unlocked(struct xa_state *xas, void *entry)
>  static void put_unlocked_entry(struct xa_state *xas, void *entry)
>  {
>  	/* If we were the only waiter woken, wake the next one */
> -	if (entry)
> +	if (entry && dax_is_conflict(entry))

This should be !dax_is_conflict(entry)...

>  		dax_wake_entry(xas, entry, false);
>  }

Otherwise the patch looks good to me so feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

once you fix this.

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR