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
WARNING: multiple messages have this Message-ID (diff)
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 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/
next reply other threads:[~2021-10-04 6:57 UTC|newest] Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-04 6:56 Sean Nyekjaer [this message] 2021-10-04 6:56 ` [RFC PATCH] mtd: rawnand: use mutex to protect access while in suspend Sean Nyekjaer 2021-10-04 8:41 ` Boris Brezillon 2021-10-04 8:41 ` Boris Brezillon 2021-10-04 8:55 ` Sean Nyekjaer 2021-10-04 8:55 ` Sean Nyekjaer 2021-10-04 9:58 ` Boris Brezillon 2021-10-04 9:58 ` Boris Brezillon 2021-10-04 10:12 ` Sean Nyekjaer 2021-10-04 10:12 ` Sean Nyekjaer 2021-10-04 11:47 ` Boris Brezillon 2021-10-04 11:47 ` Boris Brezillon 2021-10-05 7:09 ` Sean Nyekjaer 2021-10-05 7:09 ` Sean Nyekjaer 2021-10-05 8:23 ` Boris Brezillon 2021-10-05 8:23 ` Boris Brezillon 2021-10-05 8:49 ` Sean Nyekjaer 2021-10-05 8:49 ` Sean Nyekjaer 2021-10-05 8:58 ` Boris Brezillon 2021-10-05 8:58 ` Boris Brezillon 2021-10-07 11:43 ` Sean Nyekjaer 2021-10-07 11:43 ` Sean Nyekjaer 2021-10-07 12:18 ` Boris Brezillon 2021-10-07 12:18 ` Boris Brezillon 2021-10-07 12:39 ` Sean Nyekjaer 2021-10-07 12:39 ` Sean Nyekjaer 2021-10-07 13:14 ` Boris Brezillon 2021-10-07 13:14 ` Boris Brezillon 2021-10-08 10:04 ` Sean Nyekjaer 2021-10-08 10:04 ` Sean Nyekjaer 2021-10-08 11:20 ` Boris Brezillon 2021-10-08 11:20 ` Boris Brezillon 2021-10-08 11:54 ` Sean Nyekjaer 2021-10-08 11:54 ` Sean Nyekjaer 2021-10-08 12:15 ` Boris Brezillon 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 14:38 ` Sean Nyekjaer 2021-10-08 15:30 ` Boris Brezillon 2021-10-08 15:30 ` Boris Brezillon 2021-10-08 17:31 ` Sean Nyekjaer 2021-10-08 17:31 ` Sean Nyekjaer 2021-10-08 15:35 ` Miquel Raynal 2021-10-08 15:35 ` Miquel Raynal 2021-10-08 16:08 ` Boris Brezillon 2021-10-08 16:08 ` Boris Brezillon 2021-10-08 17:50 ` Sean Nyekjaer 2021-10-08 17:50 ` Sean Nyekjaer 2021-10-08 14:38 ` [RFC PATCH 2/2] mtd: rawnand: remove suspended check Sean Nyekjaer 2021-10-08 14:38 ` Sean Nyekjaer 2021-10-08 22:05 ` kernel test robot 2021-10-08 22:05 ` kernel test robot 2021-10-08 22:47 ` kernel test robot 2021-10-08 22:47 ` kernel test robot
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