From: "Michael Walle" <mwalle@kernel.org>
To: "Itai Handler" <itai.handler@gmail.com>, <pratyush@kernel.org>
Cc: <linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>,
<vigneshr@ti.com>, <richard@nod.at>, <miquel.raynal@bootlin.com>,
<takahiro.kuwano@infineon.com>
Subject: Re: [PATCH 2/2] mtd: spi-nor: take the flash lock in spi_nor_remove()
Date: Mon, 14 Sep 2026 10:32:59 +0200 [thread overview]
Message-ID: <DLEWF5DGXYAE.179JK12YIHHID@kernel.org> (raw)
In-Reply-To: <20260910184452.895485-3-itai.handler@gmail.com>
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On Thu Sep 10, 2026 at 8:44 PM CEST, Itai Handler wrote:
> spi_nor_remove() restores the addressing mode with the same unlocked
> call to spi_nor_restore() that spi_nor_shutdown() used before the
> previous patch, and it is exposed the same way: the MTD device is still
> registered at that point, so an unbind can run the restore while another
> thread is in the middle of an operation. A busy flash silently ignores
> the restore, and a restore that lands between two chunks of a read
> switches the chip to 3-byte addressing while the driver keeps sending
> 4 address bytes.
>
> Moving the restore after mtd_device_unregister() would not fix this.
> Since commit 19bfa9ebebb5 ("mtd: use refcount to prevent corruption")
> del_mtd_device() drops a reference instead of refusing with -EBUSY when
> the device is in use, so unregistering returns right away and does not
> wait for an operation that is already running.
>
> Take nor->lock for the restore, as spi_nor_shutdown() now does. The
> unregister stays unconditional, so a flash whose restore had to be
> skipped is still torn down.
Why are these two different patches? This should be folded into the
former one.
-michael
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prev parent reply other threads:[~2026-09-14 8:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-10 18:44 [PATCH 0/2] mtd: spi-nor: fix the unlocked restore on shutdown and remove Itai Handler
2026-09-10 18:44 ` [PATCH 1/2] mtd: spi-nor: take the flash lock in spi_nor_shutdown() Itai Handler
2026-09-10 19:01 ` sashiko-bot
2026-09-14 8:08 ` Itai Handler
2026-09-14 8:31 ` Michael Walle
2026-09-10 18:44 ` [PATCH 2/2] mtd: spi-nor: take the flash lock in spi_nor_remove() Itai Handler
2026-09-10 19:02 ` sashiko-bot
2026-09-14 8:11 ` Itai Handler
2026-09-14 8:32 ` Michael Walle [this message]
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