From: Sean Nyekjaer <sean@geanix.com>
To: Miquel Raynal <miquel.raynal@bootlin.com>,
Richard Weinberger <richard@nod.at>,
Vignesh Raghavendra <vigneshr@ti.com>,
Boris Brezillon <bbrezillon@kernel.org>
Cc: Sean Nyekjaer <sean@geanix.com>,
linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH] mtd: rawnand: use mutex to protect access while in suspend
Date: Mon, 4 Oct 2021 08:56:09 +0200 [thread overview]
Message-ID: <20211004065608.3190348-1-sean@geanix.com> (raw)
This will prevent nand_get_device() from returning -EBUSY.
It will force mtd_write()/mtd_read() to wait for the nand_resume() to unlock
access to the mtd device.
Then we avoid -EBUSY is returned to ubifsi via mtd_write()/mtd_read(),
that will in turn hard error on every error returened.
We have seen during ubifs tries to call mtd_write before the mtd device
is resumed.
Exec_op[0] speed things up, so we see this race when the device is
resuming. But it's actually "mtd: rawnand: Simplify the locking" that
allows it to return -EBUSY, before that commit it would have waited for
the mtd device to resume.
Tested on a iMX6ULL.
[0]:
ef347c0cfd61 ("mtd: rawnand: gpmi: Implement exec_op")
Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking")
Signed-off-by: Sean Nyekjaer <sean@geanix.com>
---
I did this a RFC as we probably will need to remove the suspended
variable as it's kinda made obsolute by this change.
Should we introduce a new mutex? Or maybe a spin_lock?
drivers/mtd/nand/raw/nand_base.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 3d6c6e880520..0ea343404cac 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -4567,7 +4567,6 @@ static int nand_suspend(struct mtd_info *mtd)
ret = chip->ops.suspend(chip);
if (!ret)
chip->suspended = 1;
- mutex_unlock(&chip->lock);
return ret;
}
@@ -4580,7 +4579,6 @@ static void nand_resume(struct mtd_info *mtd)
{
struct nand_chip *chip = mtd_to_nand(mtd);
- mutex_lock(&chip->lock);
if (chip->suspended) {
if (chip->ops.resume)
chip->ops.resume(chip);
--
2.33.0
next reply other threads:[~2021-10-04 6:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 6:56 Sean Nyekjaer [this message]
2021-10-04 8:41 ` [RFC PATCH] mtd: rawnand: use mutex to protect access while in suspend Boris Brezillon
2021-10-04 8:55 ` Sean Nyekjaer
2021-10-04 9:58 ` Boris Brezillon
2021-10-04 10:12 ` Sean Nyekjaer
2021-10-04 11:47 ` Boris Brezillon
2021-10-05 7:09 ` Sean Nyekjaer
2021-10-05 8:23 ` Boris Brezillon
2021-10-05 8:49 ` Sean Nyekjaer
2021-10-05 8:58 ` Boris Brezillon
2021-10-07 11:43 ` Sean Nyekjaer
2021-10-07 12:18 ` Boris Brezillon
2021-10-07 12:39 ` Sean Nyekjaer
2021-10-07 13:14 ` Boris Brezillon
2021-10-08 10:04 ` Sean Nyekjaer
2021-10-08 11:20 ` Boris Brezillon
2021-10-08 11:54 ` Sean Nyekjaer
2021-10-08 12:15 ` Boris Brezillon
2021-10-08 14:38 ` [RFC PATCH 1/2] mtd: core: protect access to mtd devices " Sean Nyekjaer
2021-10-08 15:30 ` Boris Brezillon
2021-10-08 17:31 ` Sean Nyekjaer
2021-10-08 15:35 ` Miquel Raynal
2021-10-08 16:08 ` Boris Brezillon
2021-10-08 17:50 ` Sean Nyekjaer
2021-10-08 14:38 ` [RFC PATCH 2/2] mtd: rawnand: remove suspended check Sean Nyekjaer
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