Commit:     1e9a51dca19dc1d8807c63cb3bd4413d3f95aaf5
Parent:     863c47028eb469c9e6c4e4287b01bea2bbf78766
Author:     Atsushi Nemoto <[EMAIL PROTECTED]>
AuthorDate: Fri Jan 26 00:56:54 2007 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Fri Jan 26 13:50:58 2007 -0800

    [PATCH] 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
    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
    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
    Signed-off-by: Atsushi Nemoto <[EMAIL PROTECTED]>
    Signed-off-by: David Brownell <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 drivers/spi/spi.c |   23 ++++++++++++++---------
 1 files changed, 14 insertions(+), 9 deletions(-)

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, unsigned size)
        master->cdev.class = &spi_master_class;
-       kobj_set_kset_s(&master->cdev, spi_master_class.subsys);
        master-> = 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;
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