DigiGoon/android_kernel_xiaomi_sm8350
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Revert "spi: Fix deadlock when adding SPI controllers on SPI buses"

Browse source 
This reverts commit aa3f3d7bef which is
commit 6098475d4cb48d821bdf453c61118c56e26294f0 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I2bd07f43254864be68c6426dc3215dcd60aa0516
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman 2024-11-21 22:00:31 +00:00
parent a1434939a5
commit 3871647ee4
2 changed files with 10 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
drivers/spi/spi.c
View file

@ -472,6 +472,12 @@ static LIST_HEAD(spi_controller_list);
*/
static DEFINE_MUTEX(board_lock);
/*
* Prevents addition of devices with same chip select and
* addition of devices below an unregistering controller.
*/
static DEFINE_MUTEX(spi_add_lock);
/**
* spi_alloc_device - Allocate a new SPI device
* @ctlr: Controller to which device is connected
@ -574,7 +580,7 @@ int spi_add_device(struct spi_device *spi)
* chipselect **BEFORE** we call setup(), else we'll trash
* its configuration. Lock against concurrent add() calls.
*/
mutex_lock(&ctlr->add_lock);
mutex_lock(&spi_add_lock);
status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
if (status) {
@ -618,7 +624,7 @@ int spi_add_device(struct spi_device *spi)
}
done:
mutex_unlock(&ctlr->add_lock);
mutex_unlock(&spi_add_lock);
return status;
}
EXPORT_SYMBOL_GPL(spi_add_device);
@ -2505,7 +2511,6 @@ int spi_register_controller(struct spi_controller *ctlr)
spin_lock_init(&ctlr->bus_lock_spinlock);
mutex_init(&ctlr->bus_lock_mutex);
mutex_init(&ctlr->io_mutex);
mutex_init(&ctlr->add_lock);
ctlr->bus_lock_flag = 0;
init_completion(&ctlr->xfer_completion);
if (!ctlr->max_dma_len)
@ -2656,7 +2661,7 @@ void spi_unregister_controller(struct spi_controller *ctlr)
/* Prevent addition of new devices, unregister existing ones */
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_lock(&ctlr->add_lock);
mutex_lock(&spi_add_lock);
device_for_each_child(&ctlr->dev, NULL, __unregister);
@ -2688,7 +2693,7 @@ void spi_unregister_controller(struct spi_controller *ctlr)
mutex_unlock(&board_lock);
if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
mutex_unlock(&ctlr->add_lock);
mutex_unlock(&spi_add_lock);
}
EXPORT_SYMBOL_GPL(spi_unregister_controller);

3
include/linux/spi/spi.h
View file

@ -480,9 +480,6 @@ struct spi_controller {
/* I/O mutex */
struct mutex io_mutex;
/* Used to avoid adding the same CS twice */
struct mutex add_lock;
/* lock and mutex for SPI bus locking */
spinlock_t bus_lock_spinlock;
struct mutex bus_lock_mutex;