On Tuesday 23 January 2007 8:07 am, Atsushi Nemoto wrote:
> On Tue, 23 Jan 2007 07:42:15 -0800, David Brownell <[EMAIL PROTECTED]> wrote:
> > > Indeed the check can be omitted. Should I send a new patch just
> > > moving class_device_get() into "if (master->bus_num == bus_num)"
> > > block?
> >
> > Yes, please.
>
> OK, here is. This patch uses spi_master_get() instead of
> class_device_get().
Much better. This should be merged for 2.6.20 ...
>
>
> Subject: SPI: alternative fix for spi_busnum_to_master
>
> If a SPI master device exists, udev (udevtrigger) causes kernel crash,
> due to wrong kobj pointer in kobject_uevent_env(). This problem was
> not in 2.6.19.
>
> The backtrace (on MIPS) was:
> [<8024db6c>] kobject_uevent_env+0x54c/0x5e8
> [<802a8264>] store_uevent+0x1c/0x3c (in drivers/class.c)
> [<801cb14c>] subsys_attr_store+0x2c/0x50
> [<801cb80c>] flush_write_buffer+0x38/0x5c
> [<801cb900>] sysfs_write_file+0xd0/0x190
> [<80181444>] vfs_write+0xc4/0x1a0
> [<80181cdc>] sys_write+0x54/0xa0
> [<8010dae4>] stack_done+0x20/0x3c
>
> flush_write_buffer() passes kobject of spi_master_class.subsys to
> subsys_addr_store(), then subsys_addr_store() passes a pointer to a
> struct subsystem to store_uevent() which expects a pointer to a struct
> class_device. The problem seems subsys_attr_store() called instead of
> class_device_attr_store().
>
> This mismatch was caused by commit
> 3bd0f6943520e459659d10f3282285e43d3990f1, which overrides kset of
> master class. This made spi_master_class.subsys.kset.ktype NULL so
> subsys_sysfs_ops is used instead of class_dev_sysfs_ops.
>
> The commit was to fix spi_busnum_to_master(). Here is a patch fixes
> this function in other way, just searching children list of
> class_device.
>
> Signed-off-by: Atsushi Nemoto <[EMAIL PROTECTED]>
> ---
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 270e621..6307428 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -366,7 +366,6 @@ spi_alloc_master(struct device *dev, uns
>
> class_device_initialize(&master->cdev);
> master->cdev.class = &spi_master_class;
> - kobj_set_kset_s(&master->cdev, spi_master_class.subsys);
> master->cdev.dev = get_device(dev);
> spi_master_set_devdata(master, &master[1]);
>
> @@ -466,14 +465,20 @@ EXPORT_SYMBOL_GPL(spi_unregister_master)
> */
> struct spi_master *spi_busnum_to_master(u16 bus_num)
> {
> - char name[9];
> - struct kobject *bus;
> -
> - snprintf(name, sizeof name, "spi%u", bus_num);
> - bus = kset_find_obj(&spi_master_class.subsys.kset, name);
> - if (bus)
> - return container_of(bus, struct spi_master, cdev.kobj);
> - return NULL;
> + struct class_device *cdev;
> + struct spi_master *master = NULL;
> + struct spi_master *m;
> +
> + down(&spi_master_class.sem);
> + list_for_each_entry(cdev, &spi_master_class.children, node) {
> + m = container_of(cdev, struct spi_master, cdev);
> + if (m->bus_num == bus_num) {
> + master = spi_master_get(m);
> + break;
> + }
> + }
> + up(&spi_master_class.sem);
> + return master;
> }
> EXPORT_SYMBOL_GPL(spi_busnum_to_master);
>
>
-
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