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commit19b8766459upstream. Each physical partition can provide multiple services each with UUID. Each such service can be presented as logical partition with a unique combination of VM ID and UUID. The number of distinct UUID in a system will be less than or equal to the number of logical partitions. However, currently it fails to register more than one logical partition or service within a physical partition as the device name contains only VM ID while both VM ID and UUID are maintained in the partition information. The kernel complains with the below message: | sysfs: cannot create duplicate filename '/devices/arm-ffa-8001' | CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc7 #8 | Hardware name: FVP Base RevC (DT) | Call trace: | dump_backtrace+0xf8/0x118 | show_stack+0x18/0x24 | dump_stack_lvl+0x50/0x68 | dump_stack+0x18/0x24 | sysfs_create_dir_ns+0xe0/0x13c | kobject_add_internal+0x220/0x3d4 | kobject_add+0x94/0x100 | device_add+0x144/0x5d8 | device_register+0x20/0x30 | ffa_device_register+0x88/0xd8 | ffa_setup_partitions+0x108/0x1b8 | ffa_init+0x2ec/0x3a4 | do_one_initcall+0xcc/0x240 | do_initcall_level+0x8c/0xac | do_initcalls+0x54/0x94 | do_basic_setup+0x1c/0x28 | kernel_init_freeable+0x100/0x16c | kernel_init+0x20/0x1a0 | ret_from_fork+0x10/0x20 | kobject_add_internal failed for arm-ffa-8001 with -EEXIST, don't try to | register things with the same name in the same directory. | arm_ffa arm-ffa: unable to register device arm-ffa-8001 err=-17 | ARM FF-A: ffa_setup_partitions: failed to register partition ID 0x8001 By virtue of being random enough to avoid collisions when generated in a distributed system, there is no way to compress UUID keys to the number of bits required to identify each. We can eliminate '-' in the name but it is not worth eliminating 4 bytes and add unnecessary logic for doing that. Also v1.0 doesn't provide the UUID of the partitions which makes it hard to use the same for the device name. So to keep it simple, let us alloc an ID using ida_alloc() and append the same to "arm-ffa" to make up a unique device name. Also stash the id value in ffa_dev to help freeing the ID later when the device is destroyed. Fixes:e781858488("firmware: arm_ffa: Add initial FFA bus support for device enumeration") Reported-by: Lucian Paul-Trifu <lucian.paul-trifu@arm.com> Link: https://lore.kernel.org/r/20230419-ffa_fixes_6-4-v2-3-d9108e43a176@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.