no_llseek had been defined to NULL two years ago, in commit 868941b
("fs: remove no_llseek")
To quote that commit,
At -rc1 we'll need do a mechanical removal of no_llseek -
git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done
would do it.
Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.
Pull driver core updates from Greg KH:
"Here is the set of driver core and kernfs changes for 6.2-rc1.
The "big" change in here is the addition of a new macro,
container_of_const() that will preserve the "const-ness" of a pointer
passed into it.
The "problem" of the current container_of() macro is that if you pass
in a "const *", out of it can comes a non-const pointer unless you
specifically ask for it. For many usages, we want to preserve the
"const" attribute by using the same call. For a specific example, this
series changes the kobj_to_dev() macro to use it, allowing it to be
used no matter what the const value is. This prevents every subsystem
from having to declare 2 different individual macros (i.e.
kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
the const value at build time, which having 2 macros would not do
either.
The driver for all of this have been discussions with the Rust kernel
developers as to how to properly mark driver core, and kobject,
objects as being "non-mutable". The changes to the kobject and driver
core in this pull request are the result of that, as there are lots of
paths where kobjects and device pointers are not modified at all, so
marking them as "const" allows the compiler to enforce this.
So, a nice side affect of the Rust development effort has been already
to clean up the driver core code to be more obvious about object
rules.
All of this has been bike-shedded in quite a lot of detail on lkml
with different names and implementations resulting in the tiny version
we have in here, much better than my original proposal. Lots of
subsystem maintainers have acked the changes as well.
Other than this change, included in here are smaller stuff like:
- kernfs fixes and updates to handle lock contention better
- vmlinux.lds.h fixes and updates
- sysfs and debugfs documentation updates
- device property updates
All of these have been in the linux-next tree for quite a while with
no problems"
* tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits)
device property: Fix documentation for fwnode_get_next_parent()
firmware_loader: fix up to_fw_sysfs() to preserve const
usb.h: take advantage of container_of_const()
device.h: move kobj_to_dev() to use container_of_const()
container_of: add container_of_const() that preserves const-ness of the pointer
driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion.
driver core: fix up missed scsi/cxlflash class.devnode() conversion.
driver core: fix up some missing class.devnode() conversions.
driver core: make struct class.devnode() take a const *
driver core: make struct class.dev_uevent() take a const *
cacheinfo: Remove of_node_put() for fw_token
device property: Add a blank line in Kconfig of tests
device property: Rename goto label to be more precise
device property: Move PROPERTY_ENTRY_BOOL() a bit down
device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*()
kernfs: fix all kernel-doc warnings and multiple typos
driver core: pass a const * into of_device_uevent()
kobject: kset_uevent_ops: make name() callback take a const *
kobject: kset_uevent_ops: make filter() callback take a const *
kobject: make kobject_namespace take a const *
...
msr-index.h should contain all MSRs for easier grepping for MSR numbers
when dealing with unchecked MSR access warnings, for example.
Move the resctrl ones. Prefix IA32_PQR_ASSOC with "MSR_" while at it.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221106212923.20699-1-bp@alien8.de
Whether CDP is enabled for a hardware resource like the L3 cache can be
found by inspecting the alloc_enabled flags of the L3CODE/L3DATA struct
rdt_hw_resources, even if they aren't in use.
Once these resources are merged, the flags can't be compared. Whether
CDP is enabled needs tracking explicitly. If another architecture is
emulating CDP the behaviour may not be per-resource. 'cdp_capable' needs
to be visible to resctrl, even if its not in use, as this affects the
padding of the schemata table visible to user-space.
Add cdp_enabled to struct rdt_hw_resource and cdp_capable to struct
rdt_resource. Add resctrl_arch_set_cdp_enabled() to let resctrl enable
or disable CDP on a resource. resctrl_arch_get_cdp_enabled() lets it
read the current state.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-12-james.morse@arm.com
resctrl is the defacto Linux ABI for SoC resource partitioning features.
To support it on another architecture, it needs to be abstracted from
the features provided by Intel RDT and AMD PQoS, and moved to /fs/.
struct rdt_resource contains a mix of architecture private details
and properties of the filesystem interface user-space uses.
Start by splitting struct rdt_resource, into an architecture private
'hw' struct, which contains the common resctrl structure that would be
used by any architecture. The foreach helpers are most commonly used by
the filesystem code, and should return the common resctrl structure.
for_each_rdt_resource() is changed to walk the common structure in its
parent arch private structure.
Move as much of the structure as possible into the common structure
in the core code's header file. The x86 hardware accessors remain
part of the architecture private code, as do num_closid, mon_scale
and mbm_width.
mon_scale and mbm_width are used to detect overflow of the hardware
counters, and convert them from their native size to bytes. Any
cross-architecture abstraction should be in terms of bytes, making
these properties private.
The hardware's num_closid is kept in the private structure to force the
filesystem code to use a helper to access it. MPAM would return a single
value for the system, regardless of the resource. Using the helper
prevents this field from being confused with the version of num_closid
that is being exposed to user-space (added in a later patch).
After this split, filesystem code touching a 'hw' struct indicates
where an abstraction is needed.
Splitting this structure only moves types around, and should not lead
to any change in behaviour.
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-2-james.morse@arm.com
Pull x86 cache resource control update from Ingo Molnar:
"Two cleanup patches"
* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/resctrl: Cleanup cbm_ensure_valid()
x86/resctrl: Use _ASM_BX to avoid ifdeffery
In commit:
4b53a3412d ("sched/core: Remove the tsk_nr_cpus_allowed() wrapper")
the tsk_nr_cpus_allowed() wrapper was removed. There was not
much difference in !RT but in RT we used this to implement
migrate_disable(). Within a migrate_disable() section the CPU mask is
restricted to single CPU while the "normal" CPU mask remains untouched.
As an alternative implementation Ingo suggested to use:
struct task_struct {
const cpumask_t *cpus_ptr;
cpumask_t cpus_mask;
};
with
t->cpus_ptr = &t->cpus_mask;
In -RT we then can switch the cpus_ptr to:
t->cpus_ptr = &cpumask_of(task_cpu(p));
in a migration disabled region. The rules are simple:
- Code that 'uses' ->cpus_allowed would use the pointer.
- Code that 'modifies' ->cpus_allowed would use the direct mask.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190423142636.14347-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
