Re: [PATCH 2/2] mtd: spi-nor: take the flash lock in spi_nor_remove()

[Michael Walle]

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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