From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, xen-devel@lists.xenproject.org,
LKML <linux-kernel@vger.kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH] xen/gntdev: fix up blockable calls to mn_invl_range_start
Date: Thu, 23 Aug 2018 15:51:51 +0200 [thread overview]
Message-ID: <20180823135151.GM29735@dhcp22.suse.cz> (raw)
In-Reply-To: <07c7ead4-334d-9b25-f588-25e9b46bbea0@i-love.sakura.ne.jp>
On Thu 23-08-18 22:44:07, Tetsuo Handa wrote:
> On 2018/08/23 21:07, Michal Hocko wrote:
> > diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> > index 57390c7666e5..e7d8bb1bee2a 100644
> > --- a/drivers/xen/gntdev.c
> > +++ b/drivers/xen/gntdev.c
> > @@ -519,21 +519,20 @@ static int mn_invl_range_start(struct mmu_notifier *mn,
> > struct gntdev_grant_map *map;
> > int ret = 0;
> >
> > - /* TODO do we really need a mutex here? */
> > if (blockable)
> > mutex_lock(&priv->lock);
> > else if (!mutex_trylock(&priv->lock))
> > return -EAGAIN;
> >
> > list_for_each_entry(map, &priv->maps, next) {
> > - if (in_range(map, start, end)) {
> > + if (!blockable && in_range(map, start, end)) {
>
> This still looks strange. Prior to 93065ac753e4, in_range() test was
> inside unmap_if_in_range(). But this patch removes in_range() test
> if blockable == true. That is, unmap_if_in_range() will unconditionally
> unmap if blockable == true, which seems to be an unexpected change.
You are right. I completely forgot I've removed in_range there. Does
this look any better?
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index e7d8bb1bee2a..30f81004ea63 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -525,14 +525,20 @@ static int mn_invl_range_start(struct mmu_notifier *mn,
return -EAGAIN;
list_for_each_entry(map, &priv->maps, next) {
- if (!blockable && in_range(map, start, end)) {
+ if (in_range(map, start, end)) {
+ if (blockable)
+ continue;
+
ret = -EAGAIN;
goto out_unlock;
}
unmap_if_in_range(map, start, end);
}
list_for_each_entry(map, &priv->freeable_maps, next) {
- if (!blockable && in_range(map, start, end)) {
+ if (in_range(map, start, end)) {
+ if (blockable)
+ continue;
+
ret = -EAGAIN;
goto out_unlock;
}
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-08-23 13:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-23 12:07 [PATCH] xen/gntdev: fix up blockable calls to mn_invl_range_start Michal Hocko
2018-08-23 13:44 ` Tetsuo Handa
2018-08-23 13:51 ` Michal Hocko [this message]
2018-08-23 14:06 ` Boris Ostrovsky
2018-08-23 19:09 ` Michal Hocko
2018-08-24 5:03 ` Juergen Gross
2018-08-24 7:49 ` Michal Hocko
2018-08-23 14:20 ` Tetsuo Handa
2018-08-23 13:46 ` Boris Ostrovsky
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=20180823135151.GM29735@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=boris.ostrovsky@oracle.com \
--cc=jgross@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=xen-devel@lists.xenproject.org \
/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).