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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2021-10-18 22:40:28 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-11-26 11:58:45 +0100
commitad4775bdacf90902b80ea56f2aa5117f9750db74 (patch)
treed68480af9fb61107a3cb70715789ea02c76b9f8e
parent3439d462e091bd86bff1aa06480702162030fa58 (diff)
usb: max-3421: Use driver data instead of maintaining a list of bound devices
commit fc153aba3ef371d0d76eb88230ed4e0dee5b38f2 upstream. Instead of maintaining a single-linked list of devices that must be searched linearly in .remove() just use spi_set_drvdata() to remember the link between the spi device and the driver struct. Then the global list and the next member can be dropped. This simplifies the driver, reduces the memory footprint and the time to search the list. Also it makes obvious that there is always a corresponding driver struct for a given device in .remove(), so the error path for !max3421_hcd can be dropped, too. As a side effect this fixes a data inconsistency when .probe() races with itself for a second max3421 device in manipulating max3421_hcd_list. A similar race is fixed in .remove(), too. Fixes: 2d53139f3162 ("Add support for using a MAX3421E chip as a host driver.") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20211018204028.2914597-1-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/host/max3421-hcd.c25
1 files changed, 5 insertions, 20 deletions
diff --git a/drivers/usb/host/max3421-hcd.c b/drivers/usb/host/max3421-hcd.c
index 2f8a5fa28a80..f30e661129c2 100644
--- a/drivers/usb/host/max3421-hcd.c
+++ b/drivers/usb/host/max3421-hcd.c
@@ -121,8 +121,6 @@ struct max3421_hcd {
struct task_struct *spi_thread;
- struct max3421_hcd *next;
-
enum max3421_rh_state rh_state;
/* lower 16 bits contain port status, upper 16 bits the change mask: */
u32 port_status;
@@ -170,8 +168,6 @@ struct max3421_ep {
u8 retransmit; /* packet needs retransmission */
};
-static struct max3421_hcd *max3421_hcd_list;
-
#define MAX3421_FIFO_SIZE 64
#define MAX3421_SPI_DIR_RD 0 /* read register from MAX3421 */
@@ -1841,9 +1837,8 @@ max3421_probe(struct spi_device *spi)
}
set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
max3421_hcd = hcd_to_max3421(hcd);
- max3421_hcd->next = max3421_hcd_list;
- max3421_hcd_list = max3421_hcd;
INIT_LIST_HEAD(&max3421_hcd->ep_list);
+ spi_set_drvdata(spi, max3421_hcd);
max3421_hcd->tx = kmalloc(sizeof(*max3421_hcd->tx), GFP_KERNEL);
if (!max3421_hcd->tx) {
@@ -1892,28 +1887,18 @@ error:
static int
max3421_remove(struct spi_device *spi)
{
- struct max3421_hcd *max3421_hcd = NULL, **prev;
- struct usb_hcd *hcd = NULL;
+ struct max3421_hcd *max3421_hcd;
+ struct usb_hcd *hcd;
unsigned long flags;
- for (prev = &max3421_hcd_list; *prev; prev = &(*prev)->next) {
- max3421_hcd = *prev;
- hcd = max3421_to_hcd(max3421_hcd);
- if (hcd->self.controller == &spi->dev)
- break;
- }
- if (!max3421_hcd) {
- dev_err(&spi->dev, "no MAX3421 HCD found for SPI device %p\n",
- spi);
- return -ENODEV;
- }
+ max3421_hcd = spi_get_drvdata(spi);
+ hcd = max3421_to_hcd(max3421_hcd);
usb_remove_hcd(hcd);
spin_lock_irqsave(&max3421_hcd->lock, flags);
kthread_stop(max3421_hcd->spi_thread);
- *prev = max3421_hcd->next;
spin_unlock_irqrestore(&max3421_hcd->lock, flags);