4.18-stable review patch. If anyone has any objections, please let me know.
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From: Kirill Kapranov kirill.kapranov@compulab.co.il
commit 1a4327fbf4554d5b78d75b19a13d40d6de220159 upstream.
On systems where some controllers get a dynamic ID assigned and some have a fixed number (e.g. from ACPI tables), the current implementation might run into an IDR collision: in case of a fixed bus number is gotten by a driver (but not marked busy in IDR tree) and a driver with dynamic bus number gets the same ID and predictably fails.
Fix this by means of checking-in fixed IDsin IDR as far as dynamic ones at the moment of the controller registration.
Fixes: 9b61e302210e (spi: Pick spi bus number from Linux idr or spi alias) Signed-off-by: Kirill Kapranov kirill.kapranov@compulab.co.il Signed-off-by: Mark Brown broonie@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/spi/spi.c | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2170,6 +2170,15 @@ int spi_register_controller(struct spi_c if (WARN(id < 0, "couldn't get idr")) return id; ctlr->bus_num = id; + } else { + /* devices with a fixed bus num must check-in with the num */ + mutex_lock(&board_lock); + id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num, + ctlr->bus_num + 1, GFP_KERNEL); + mutex_unlock(&board_lock); + if (WARN(id < 0, "couldn't get idr")) + return id == -ENOSPC ? -EBUSY : id; + ctlr->bus_num = id; } INIT_LIST_HEAD(&ctlr->queue); spin_lock_init(&ctlr->queue_lock);