As of now, seeking in sysfs files is handled by generic_file_llseek().
There are situations where one may want to customize seeking logic:
- Many sysfs entries are fixed files while generic_file_llseek() accepts
past-the-end positions. Not only being useless by itself, this
also means a bug in userspace code will trigger not at lseek(), but at
some later point making debugging harder.
- generic_file_llseek() relies on f_mapping->host to get the file size
which might not be correct for all sysfs entries.
See commit 636b21b501 ("PCI: Revoke mappings like devmem") as an example.
Implement llseek method to override this behavior at sysfs attribute
level. The method is optional, and if it is absent,
generic_file_llseek() is called to preserve backwards compatibility.
Signed-off-by: Valentine Sinitsyn <valesini@yandex-team.ru>
Link: https://lore.kernel.org/r/20230925084013.309399-1-valesini@yandex-team.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Most sysfs attributes are statically defined, the goal with this design
being to be able to move all the filesystem description into read-only
memory. Anyway, it may be relevant in some cases to populate attributes
at run time. This leads to situation where an attribute may or may not be
present depending on conditions which are not known at compile
time, up to the point where no attribute at all gets added in a folder
which then becomes "sometimes" empty. Problem is, providing an attribute
group with a name and without .[bin_]attrs members will be loudly
refused by the core, leading in most cases to a device registration
failure.
The simple way to support such situation right now is to dynamically
allocate an empty attribute array, which is:
* a (small) waste of space
* a waste of time
* disturbing, to say the least, as an empty sysfs folder will be created
anyway.
Another (even worse) possibility would be to dynamically overwrite a
member of the attribute_group list, hopefully the last, which is also
supposed to remain in the read-only section.
In order to avoid these hackish situations, while still giving a little
bit of flexibility, we might just check the validity of the .[bin_]attrs
list and, if empty, just skip the attribute group creation instead of
failing. This way, developers will not be tempted to workaround the
core with useless allocations or strange writes on supposedly read-only
structures.
The content of the WARN() message is kept but turned into a debug
message in order to help developers understanding why their sysfs
folders might now silently fail to be created.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Message-ID: <20230614063018.2419043-3-miquel.raynal@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The purpose of the if/else block is to select the right sysfs directory
entry to be used for the files creation. At a first look when you have
the file in front of you, it really seems like the "create_files()"
lines right after the block are badly indented and the "else" does not
guard. In practice the code is correct but lacks curly brackets to show
where the big if/else block actually ends. Add these brackets to comply
with the current kernel coding style and to ease the understanding of
the whole logic.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Message-ID: <20230614063018.2419043-2-miquel.raynal@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that all in-kernel users of default_attrs for the kobj_type are gone
and converted to properly use the default_groups pointer instead, it can
be safely removed.
There is one standard way to create sysfs files in a kobj_type, and not
two like before, causing confusion as to which should be used.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20220106133151.607703-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs: Allow deferred execution of iomem_get_mapping()
Tag for toerh trees/branches to pull from in order to have a stable base
to build off of for the "Allow deferred execution of
iomem_get_mapping()" set of sysfs changes
Link: https://lore.kernel.org/r/20210729233235.1508920-1-kw@linux.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tag 'sysfs_defferred_iomem_get_mapping-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
sysfs: Rename struct bin_attribute member to f_mapping
sysfs: Invoke iomem_get_mapping() from the sysfs open callback
There are two users of iomem_get_mapping(), the struct file and struct
bin_attribute. The former has a member called "f_mapping" and the
latter has a member called "mapping", and both are poniters to struct
address_space.
Rename struct bin_attribute member to "f_mapping" to keep both meaning
and the usage consistent with other users of iomem_get_mapping().
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20210729233235.1508920-3-kw@linux.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Defer invocation of the iomem_get_mapping() to the sysfs open callback
so that it can be executed as needed when the binary sysfs object has
been accessed.
To do that, convert the "mapping" member of the struct bin_attribute
from a pointer to the struct address_space into a function pointer with
a signature that requires the same return type, and then updates the
sysfs_kf_bin_open() to invoke provided function should the function
pointer be valid.
Also, convert every invocation of iomem_get_mapping() into a function
pointer assignment, therefore allowing for the iomem_get_mapping()
invocation to be deferred to when the sysfs open callback runs.
Thus, this change removes the need for the fs_initcalls to complete
before any other sub-system that uses the iomem_get_mapping() would be
able to invoke it safely without leading to a failure and an Oops
related to an invalid iomem_get_mapping() access.
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20210729233235.1508920-2-kw@linux.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Output defects can exist in sysfs content using sprintf and snprintf.
sprintf does not know the PAGE_SIZE maximum of the temporary buffer
used for outputting sysfs content and it's possible to overrun the
PAGE_SIZE buffer length.
Add a generic sysfs_emit function that knows that the size of the
temporary buffer and ensures that no overrun is done.
Add a generic sysfs_emit_at function that can be used in multiple
call situations that also ensures that no overrun is done.
Validate the output buffer argument to be page aligned.
Validate the offset len argument to be within the PAGE_SIZE buf.
Signed-off-by: Joe Perches <joe@perches.com>
Link: https://lore.kernel.org/r/884235202216d464d61ee975f7465332c86f76b2.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull rdma updates from Jason Gunthorpe:
"A more active cycle than most of the recent past, with a few large,
long discussed works this time.
The RNBD block driver has been posted for nearly two years now, and
flowing through RDMA due to it also introducing a new ULP.
The removal of FMR has been a recurring discussion theme for a long
time.
And the usual smattering of features and bug fixes.
Summary:
- Various small driver bugs fixes in rxe, mlx5, hfi1, and efa
- Continuing driver cleanups in bnxt_re, hns
- Big cleanup of mlx5 QP creation flows
- More consistent use of src port and flow label when LAG is used and
a mlx5 implementation
- Additional set of cleanups for IB CM
- 'RNBD' network block driver and target. This is a network block
RDMA device specific to ionos's cloud environment. It brings strong
multipath and resiliency capabilities.
- Accelerated IPoIB for HFI1
- QP/WQ/SRQ ioctl migration for uverbs, and support for multiple
async fds
- Support for exchanging the new IBTA defiend ECE data during RDMA CM
exchanges
- Removal of the very old and insecure FMR interface from all ULPs
and drivers. FRWR should be preferred for at least a decade now"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (247 commits)
RDMA/cm: Spurious WARNING triggered in cm_destroy_id()
RDMA/mlx5: Return ECE DC support
RDMA/mlx5: Don't rely on FW to set zeros in ECE response
RDMA/mlx5: Return an error if copy_to_user fails
IB/hfi1: Use free_netdev() in hfi1_netdev_free()
RDMA/hns: Uninitialized variable in modify_qp_init_to_rtr()
RDMA/core: Move and rename trace_cm_id_create()
IB/hfi1: Fix hfi1_netdev_rx_init() error handling
RDMA: Remove 'max_map_per_fmr'
RDMA: Remove 'max_fmr'
RDMA/core: Remove FMR device ops
RDMA/rdmavt: Remove FMR memory registration
RDMA/mthca: Remove FMR support for memory registration
RDMA/mlx4: Remove FMR support for memory registration
RDMA/i40iw: Remove FMR leftovers
RDMA/bnxt_re: Remove FMR leftovers
RDMA/mlx5: Remove FMR leftovers
RDMA/core: Remove FMR pool API
RDMA/rds: Remove FMR support for memory registration
RDMA/srp: Remove support for FMR memory registration
...
Commit 9255782f70 ("sysfs: Wrap __compat_only_sysfs_link_entry_to_kobj
function to change the symlink name") made this function a wrapper
around a new non-underscored function, which is a bit odd. The normal
naming convention is the other way around: the underscored function is
the wrappee, and the non-underscored function is the wrapper.
There's only one single user (well, two call-sites in that user) of the
more limited double underscore version of this function, so just remove
the oddly named wrapper entirely and just add the extra NULL argument to
the user.
I considered just doing that in the merge, but that tends to make
history really hard to read.
Link: https://lore.kernel.org/lkml/CAHk-=wgkkmNV5tMzQDmPAQuNJBuMcry--Jb+h8H1o4RA3kF7QQ@mail.gmail.com/
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull powerpc updates from Michael Ellerman:
"Slightly late as I had to rebase mid-week to insert a bug fix:
- A large series from Nick for 64-bit to further rework our exception
vectors, and rewrite portions of the syscall entry/exit and
interrupt return in C. The result is much easier to follow code
that is also faster in general.
- Cleanup of our ptrace code to split various parts out that had
become badly intertwined with #ifdefs over the years.
- Changes to our NUMA setup under the PowerVM hypervisor which should
hopefully avoid non-sensical topologies which can lead to warnings
from the workqueue code and other problems.
- MAINTAINERS updates to remove some of our old orphan entries and
update the status of others.
- Quite a few other small changes and fixes all over the map.
Thanks to: Abdul Haleem, afzal mohammed, Alexey Kardashevskiy, Andrew
Donnellan, Aneesh Kumar K.V, Balamuruhan S, Cédric Le Goater, Chen
Zhou, Christophe JAILLET, Christophe Leroy, Christoph Hellwig, Clement
Courbet, Daniel Axtens, David Gibson, Douglas Miller, Fabiano Rosas,
Fangrui Song, Ganesh Goudar, Gautham R. Shenoy, Greg Kroah-Hartman,
Greg Kurz, Gustavo Luiz Duarte, Hari Bathini, Ilie Halip, Jan Kara,
Joe Lawrence, Joe Perches, Kajol Jain, Larry Finger, Laurentiu Tudor,
Leonardo Bras, Libor Pechacek, Madhavan Srinivasan, Mahesh Salgaonkar,
Masahiro Yamada, Masami Hiramatsu, Mauricio Faria de Oliveira, Michael
Neuling, Michal Suchanek, Mike Rapoport, Nageswara R Sastry, Nathan
Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick
Desaulniers, Oliver O'Halloran, Po-Hsu Lin, Pratik Rajesh Sampat,
Rasmus Villemoes, Ravi Bangoria, Roman Bolshakov, Sam Bobroff,
Sandipan Das, Santosh S, Sedat Dilek, Segher Boessenkool, Shilpasri G
Bhat, Sourabh Jain, Srikar Dronamraju, Stephen Rothwell, Tyrel
Datwyler, Vaibhav Jain, YueHaibing"
* tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits)
powerpc: Make setjmp/longjmp signature standard
powerpc/cputable: Remove unnecessary copy of cpu_spec->oprofile_type
powerpc: Suppress .eh_frame generation
powerpc: Drop -fno-dwarf2-cfi-asm
powerpc/32: drop unused ISA_DMA_THRESHOLD
powerpc/powernv: Add documentation for the opal sensor_groups sysfs interfaces
selftests/powerpc: Fix try-run when source tree is not writable
powerpc/vmlinux.lds: Explicitly retain .gnu.hash
powerpc/ptrace: move ptrace_triggered() into hw_breakpoint.c
powerpc/ptrace: create ppc_gethwdinfo()
powerpc/ptrace: create ptrace_get_debugreg()
powerpc/ptrace: split out ADV_DEBUG_REGS related functions.
powerpc/ptrace: move register viewing functions out of ptrace.c
powerpc/ptrace: split out TRANSACTIONAL_MEM related functions.
powerpc/ptrace: split out SPE related functions.
powerpc/ptrace: split out ALTIVEC related functions.
powerpc/ptrace: split out VSX related functions.
powerpc/ptrace: drop PARAMETER_SAVE_AREA_OFFSET
powerpc/ptrace: drop unnecessary #ifdefs CONFIG_PPC64
powerpc/ptrace: remove unused header includes
...
Add a helper to change the owner of sysfs objects.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
This mirrors how a kobject is added through driver core which in its guts is
done via kobject_add_internal() which in summary creates the main directory via
create_dir(), populates that directory with the groups associated with the
ktype of the kobject (if any) and populates the directory with the basic
attributes associated with the ktype of the kobject (if any). These are the
basic steps that are associated with adding a kobject in sysfs.
Any additional properties are added by the specific subsystem itself (not by
driver core) after it has registered the device. So for the example of network
devices, a network device will e.g. register a queue subdirectory under the
basic sysfs directory for the network device and than further subdirectories
within that queues subdirectory. But that is all specific to network devices
and they call the corresponding sysfs functions to do that directly when they
create those queue objects. So anything that a subsystem adds outside of what
driver core does must also be changed by it (That's already true for removal of
files it created outside of driver core.) and it's the same for ownership
changes.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add helpers to change the owner of sysfs groups.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a helper to change the owner of a sysfs link.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add helpers to change the owner of a sysfs files.
This function will be used to correctly account for kobject ownership
changes, e.g. when moving network devices between network namespaces.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The __compat_only_sysfs_link_entry_to_kobj function creates a symlink
to a kobject but doesn't provide an option to change the symlink file
name.
This patch adds a wrapper function compat_only_sysfs_link_entry_to_kobj
that extends the __compat_only_sysfs_link_entry_to_kobj functionality
which allows function caller to customize the symlink name.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
[mpe: Fix compile error when CONFIG_SYSFS=n]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191211160910.21656-3-sourabhjain@linux.ibm.com
