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From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-kernel@vger.kernel.org, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	linux-nvme@lists.infradead.org,
	David Jeffery <djeffery@redhat.com>,
	Laurence Oberman <loberman@redhat.com>,
	Paolo Valente <paolo.valente@linaro.org>, Jan Kara <jack@suse.cz>,
	Sasha Levin <sashal@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Keith Busch <kbusch@kernel.org>
Subject: Re: New warning in nvme_setup_discard
Date: Fri, 16 Jul 2021 07:53:28 +0200	[thread overview]
Message-ID: <81322754.HEIg0oD171@natalenko.name> (raw)
In-Reply-To: <YPDr8ucoDCE4NBSe@T590>

Hello.

On pátek 16. července 2021 4:16:18 CEST Ming Lei wrote:
> >  850     if (WARN_ON_ONCE(n != segments)) {
> 
> What is 'n' and 'segments'?

So, I used this change to check that:

```
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 66973bb56305..0a64f2f77daf 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -847,7 +847,8 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, 
struct request *req,
 		n++;
 	}
 
-	if (WARN_ON_ONCE(n != segments)) {
+	if (unlikely(n != segments)) {
+		pr_warn("nvme_setup_discard: n != segments (%u != %u)\n", n, 
segments);
 		if (virt_to_page(range) == ns->ctrl->discard_page)
 			clear_bit_unlock(0, &ns->ctrl->discard_page_busy);
 		else

```

and the result is:

```
nvme_setup_discard: n != segments (3 != 2)
nvme_setup_discard: n != segments (12 != 11)
```

(those are from different boots)

Thanks.

-- 
Oleksandr Natalenko (post-factum)



WARNING: multiple messages have this Message-ID (diff)
From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-kernel@vger.kernel.org, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	linux-nvme@lists.infradead.org,
	David Jeffery <djeffery@redhat.com>,
	Laurence Oberman <loberman@redhat.com>,
	Paolo Valente <paolo.valente@linaro.org>, Jan Kara <jack@suse.cz>,
	Sasha Levin <sashal@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Keith Busch <kbusch@kernel.org>
Subject: Re: New warning in nvme_setup_discard
Date: Fri, 16 Jul 2021 07:53:28 +0200	[thread overview]
Message-ID: <81322754.HEIg0oD171@natalenko.name> (raw)
In-Reply-To: <YPDr8ucoDCE4NBSe@T590>

Hello.

On pátek 16. července 2021 4:16:18 CEST Ming Lei wrote:
> >  850     if (WARN_ON_ONCE(n != segments)) {
> 
> What is 'n' and 'segments'?

So, I used this change to check that:

```
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 66973bb56305..0a64f2f77daf 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -847,7 +847,8 @@ static blk_status_t nvme_setup_discard(struct nvme_ns *ns, 
struct request *req,
 		n++;
 	}
 
-	if (WARN_ON_ONCE(n != segments)) {
+	if (unlikely(n != segments)) {
+		pr_warn("nvme_setup_discard: n != segments (%u != %u)\n", n, 
segments);
 		if (virt_to_page(range) == ns->ctrl->discard_page)
 			clear_bit_unlock(0, &ns->ctrl->discard_page_busy);
 		else

```

and the result is:

```
nvme_setup_discard: n != segments (3 != 2)
nvme_setup_discard: n != segments (12 != 11)
```

(those are from different boots)

Thanks.

-- 
Oleksandr Natalenko (post-factum)



_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2021-07-16  5:53 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15 13:56 New warning in nvme_setup_discard Oleksandr Natalenko
2021-07-15 13:56 ` Oleksandr Natalenko
2021-07-15 14:19 ` Greg Kroah-Hartman
2021-07-15 14:19   ` Greg Kroah-Hartman
2021-07-15 14:21   ` Oleksandr Natalenko
2021-07-15 14:21     ` Oleksandr Natalenko
2021-07-15 21:37   ` Laurence Oberman
2021-07-15 21:37     ` Laurence Oberman
2021-07-16  5:50     ` Oleksandr Natalenko
2021-07-16  5:50       ` Oleksandr Natalenko
2021-07-16  2:16 ` Ming Lei
2021-07-16  2:16   ` Ming Lei
2021-07-16  5:53   ` Oleksandr Natalenko [this message]
2021-07-16  5:53     ` Oleksandr Natalenko
2021-07-16  9:33     ` Ming Lei
2021-07-16  9:33       ` Ming Lei
2021-07-16 10:03       ` Oleksandr Natalenko
2021-07-16 10:03         ` Oleksandr Natalenko
2021-07-16 10:41         ` Ming Lei
2021-07-16 10:41           ` Ming Lei
2021-07-16 12:56           ` Oleksandr Natalenko
2021-07-16 12:56             ` Oleksandr Natalenko
2021-07-17  9:35             ` Ming Lei
2021-07-17  9:35               ` Ming Lei
2021-07-17 12:11               ` Oleksandr Natalenko
2021-07-17 12:11                 ` Oleksandr Natalenko
2021-07-17 12:19                 ` Oleksandr Natalenko
2021-07-17 12:19                   ` Oleksandr Natalenko
2021-07-17 12:35                   ` Oleksandr Natalenko
2021-07-17 12:35                     ` Oleksandr Natalenko
2021-07-19  1:40                     ` Ming Lei
2021-07-19  1:40                       ` Ming Lei
2021-07-19  6:27                       ` Oleksandr Natalenko
2021-07-19  6:27                         ` Oleksandr Natalenko
2021-07-20  9:05                         ` Oleksandr Natalenko
2021-07-20  9:05                           ` Oleksandr Natalenko
2021-07-21  8:00                           ` Ming Lei
2021-07-21  8:00                             ` Ming Lei
2021-07-27 15:12                             ` Oleksandr Natalenko
2021-07-27 15:12                               ` Oleksandr Natalenko
2021-07-27 15:58                               ` Ming Lei
2021-07-27 15:58                                 ` Ming Lei
2021-07-28 13:44                                 ` Oleksandr Natalenko
2021-07-28 13:44                                   ` Oleksandr Natalenko
2021-07-28 15:53                                   ` Ming Lei
2021-07-28 15:53                                     ` Ming Lei
2021-07-28 16:38                                     ` Oleksandr Natalenko
2021-07-28 16:38                                       ` Oleksandr Natalenko
2021-07-29  3:33                                       ` Ming Lei
2021-07-29  3:33                                         ` Ming Lei
2021-07-29  9:29                                         ` Ming Lei
2021-07-29  9:29                                           ` Ming Lei

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