[lkml]   [2018]   [Aug]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] spi:fix IDR collision on systems with both fixed and dynamic SPI bus numbers
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 <>
drivers/spi/spi.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index ec395a6baf9c..97e303185d5b 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2170,6 +2170,15 @@ int spi_register_controller(struct spi_controller *ctlr)
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;
 \ /
  Last update: 2018-08-13 19:32    [W:0.076 / U:1.828 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site