sysfs: constify bin_attribute argument of sysfs_bin_attr_simple_read()

Most users use this function through the BIN_ATTR_SIMPLE* macros,
they can handle the switch transparently.
Also adapt the two

sysfs: constify bin_attribute argument of sysfs_bin_attr_simple_read()

Most users use this function through the BIN_ATTR_SIMPLE* macros,
they can handle the switch transparently.
Also adapt the two non-macro users in the same change.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Madhavan Srinivasan <[email protected]>
Reviewed-by: Mahesh Salgaonkar <[email protected]>
Tested-by: Aditya Gupta <[email protected]>
Link: https://lore.kernel.org/r/20241228-sysfs-const-bin_attr-simple-v2-1-7c6f3f1767a3@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sysfs: constify macro BIN_ATTRIBUTE_GROUPS()

As there is only one in-tree user, avoid a transition phase and switch
that user in the same commit. As there are some interdependencies
between the cons

sysfs: constify macro BIN_ATTRIBUTE_GROUPS()

As there is only one in-tree user, avoid a transition phase and switch
that user in the same commit. As there are some interdependencies
between the constness of the different symbols in the s390 driver,
covert the whole driver at once.

Signed-off-by: Thomas Weißschuh <[email protected]>
Link: https://lore.kernel.org/r/20241205-sysfs-const-bin_attr-groups_macro-v1-1-ac5e855031e8@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: attribute_group: allow registration of const bin_attribute

To be able to constify instances of struct bin_attribute it has to be
possible to add them to string attribute_group.
The current ty

sysfs: attribute_group: allow registration of const bin_attribute

To be able to constify instances of struct bin_attribute it has to be
possible to add them to string attribute_group.
The current type of the bin_attrs member however is not compatible with
that.
Introduce a union that allows registration of both const and non-const
attributes to enable a piecewise transition.
As both union member types are compatible no logic needs to be adapted.

Technically it is now possible register a const struct
bin_attribute and receive it as mutable pointer in the callbacks.
This is a soundness issue.
But this same soundness issue already exists today in
sysfs_create_bin_file().
Also the struct definition and callback implementation are always
closely linked and are meant to be moved to const in lockstep.

Signed-off-by: Thomas Weißschuh <[email protected]>
Link: https://lore.kernel.org/r/20241115-b4-sysfs-const-bin_attr-group-v1-1-2c9bb12dfc48@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: bin_attribute: add const read/write callback variants

To make it possible to put struct bin_attribute into read-only memory,
the sysfs core has to stop passing mutable pointers to the read()

sysfs: bin_attribute: add const read/write callback variants

To make it possible to put struct bin_attribute into read-only memory,
the sysfs core has to stop passing mutable pointers to the read() and
write() callbacks.
As there are numerous implementors of these callbacks throughout the
tree it's not possible to change all of them at once.
To enable a step-by-step transition, add new variants of the read() and
write() callbacks which differ only in the constness of the struct
bin_attribute argument.

As most binary attributes are defined through macros, extend these
macros to transparently handle both variants of callbacks to minimize
the churn during the transition.
As soon as all handlers are switch to the const variant, the non-const
one can be removed together with the transition machinery.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: implement all BIN_ATTR_* macros in terms of __BIN_ATTR()

The preparations for the upcoming constification of struct bin_attribute
requires some logic in the structure definition macros.
To av

sysfs: implement all BIN_ATTR_* macros in terms of __BIN_ATTR()

The preparations for the upcoming constification of struct bin_attribute
requires some logic in the structure definition macros.
To avoid duplication of that logic in multiple macros, reimplement all
other macros in terms of __BIN_ATTR().

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: treewide: constify attribute callback of bin_attribute::llseek()

The llseek() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as

sysfs: treewide: constify attribute callback of bin_attribute::llseek()

The llseek() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as const.

As there are not many callback implementers perform this change
throughout the tree at once.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sysfs: treewide: constify attribute callback of bin_attribute::mmap()

The mmap() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as cons

sysfs: treewide: constify attribute callback of bin_attribute::mmap()

The mmap() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as const.

As there are not many callback implementers perform this change
throughout the tree at once.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Andrew Donnellan <[email protected]> # ocxl
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: treewide: constify attribute callback of bin_is_visible()

The is_bin_visible() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as

sysfs: treewide: constify attribute callback of bin_is_visible()

The is_bin_visible() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as const.

As there are not many callback implementers perform this change
throughout the tree at once.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Martin K. Petersen <[email protected]>
Acked-by: Jason Gunthorpe <[email protected]>
Acked-by: Ira Weiny <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: introduce callback attribute_group::bin_size

Several drivers need to dynamically calculate the size of an binary
attribute. Currently this is done by assigning attr->size from the
is_bin_visi

sysfs: introduce callback attribute_group::bin_size

Several drivers need to dynamically calculate the size of an binary
attribute. Currently this is done by assigning attr->size from the
is_bin_visible() callback.

This has drawbacks:
* It is not documented.
* A single attribute can be instantiated multiple times, overwriting the
shared size field.
* It prevents the structure to be moved to read-only memory.

Introduce a new dedicated callback to calculate the size of the
attribute.

Signed-off-by: Thomas Weißschuh <[email protected]>
Acked-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: Unbreak the build around sysfs_bin_attr_simple_read()

Günter reports build breakage for m68k "m5208evb_defconfig" plus
CONFIG_BLK_DEV_INITRD=y caused by commit 66bc1a173328 ("treewide:
Use sy

sysfs: Unbreak the build around sysfs_bin_attr_simple_read()

Günter reports build breakage for m68k "m5208evb_defconfig" plus
CONFIG_BLK_DEV_INITRD=y caused by commit 66bc1a173328 ("treewide:
Use sysfs_bin_attr_simple_read() helper").

The defconfig disables CONFIG_SYSFS, so sysfs_bin_attr_simple_read()
is not compiled into the kernel. But init/initramfs.c references
that function in the initializer of a struct bin_attribute.

Add an empty static inline to avoid the build breakage.

Fixes: 66bc1a173328 ("treewide: Use sysfs_bin_attr_simple_read() helper")
Reported-by: Guenter Roeck <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Signed-off-by: Lukas Wunner <[email protected]>
Tested-by: Guenter Roeck <[email protected]>
Reviewed-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/05f4290439a58730738a15b0c99cd8576c4aa0d9.1716461752.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: Add sysfs_bin_attr_simple_read() helper

When drivers expose a bin_attribute in sysfs which is backed by a buffer
in memory, a common pattern is to set the @private and @size members in
struct

sysfs: Add sysfs_bin_attr_simple_read() helper

When drivers expose a bin_attribute in sysfs which is backed by a buffer
in memory, a common pattern is to set the @private and @size members in
struct bin_attribute to the buffer's location and size.

The ->read() callback then merely consists of a single memcpy() call.
It's not even necessary to perform bounds checks as these are already
handled by sysfs_kf_bin_read().

However each driver is so far providing its own ->read() implementation.
The pattern is sufficiently frequent to merit a public helper, so add
sysfs_bin_attr_simple_read() as well as BIN_ATTR_SIMPLE_RO() and
BIN_ATTR_SIMPLE_ADMIN_RO() macros to ease declaration of such
bin_attributes and reduce LoC and .text section size.

Signed-off-by: Lukas Wunner <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Link: https://lore.kernel.org/r/5ed62b197a442ec6db53d8746d9d806dd0576e2d.1712410202.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE()

One of the first users of DEFINE_SYSFS_GROUP_VISIBLE() did this:

static umode_t dp0_attr_visible(struct kobject *kobj,
struct attribute *a

sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE()

One of the first users of DEFINE_SYSFS_GROUP_VISIBLE() did this:

static umode_t dp0_attr_visible(struct kobject *kobj,
struct attribute *attr,
int n)
{
struct sdw_slave *slave = dev_to_sdw_dev(kobj_to_dev(kobj));

if (slave->prop.dp0_prop)
return attr->mode;
return 0;
}

static bool dp0_group_visible(struct kobject *kobj)
{
struct sdw_slave *slave = dev_to_sdw_dev(kobj_to_dev(kobj));

if (slave->prop.dp0_prop)
return true;
return false;
}
DEFINE_SYSFS_GROUP_VISIBLE(dp0);

...i.e. the _group_visible() helper is identical to the _attr_visible()
helper. Use the "simple" helper to reduce that to:

static bool dp0_group_visible(struct kobject *kobj)
{
struct sdw_slave *slave = dev_to_sdw_dev(kobj_to_dev(kobj));

if (slave->prop.dp0_prop)
return true;
return false;
}
DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(dp0);

Remove the need to specify per attribute visibility if the goal is to
hide the entire group.

Signed-off-by: Dan Williams <[email protected]>
Link: https://lore.kernel.org/r/170863446625.1479840.10593839479268727913.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: Document new "group visible" helpers

Add documentation and examples for how to use
DEFINE_SYSFS_GROUP_VISIBLE() and SYSFS_GROUP_VISIBLE(). Recall that the
motivation for this work is that it

sysfs: Document new "group visible" helpers

Add documentation and examples for how to use
DEFINE_SYSFS_GROUP_VISIBLE() and SYSFS_GROUP_VISIBLE(). Recall that the
motivation for this work is that it is easier to reason about the
lifetime of statically defined sysfs attributes that become visible at
device_add() time rather than dynamically adding them later.
DEFINE_SYSFS_GROUP_VISIBLE() tackles one of the reasons to opt for
dynamically created attributes which did not have a facility for hiding
empty directories.

Signed-off-by: Dan Williams <[email protected]>
Link: https://lore.kernel.org/r/170863446065.1479840.10697164014098377292.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sysfs: Introduce a mechanism to hide static attribute_groups

Add a mechanism for named attribute_groups to hide their directory at
sysfs_update_group() time, or otherwise skip emitting the group
dir

sysfs: Introduce a mechanism to hide static attribute_groups

Add a mechanism for named attribute_groups to hide their directory at
sysfs_update_group() time, or otherwise skip emitting the group
directory when the group is first registered. It piggybacks on
is_visible() in a similar manner as SYSFS_PREALLOC, i.e. special flags
in the upper bits of the returned mode. To use it, specify a symbol
prefix to DEFINE_SYSFS_GROUP_VISIBLE(), and then pass that same prefix
to SYSFS_GROUP_VISIBLE() when assigning the @is_visible() callback:

DEFINE_SYSFS_GROUP_VISIBLE($prefix)

struct attribute_group $prefix_group = {
.name = $name,
.is_visible = SYSFS_GROUP_VISIBLE($prefix),
};

SYSFS_GROUP_VISIBLE() expects a definition of $prefix_group_visible()
and $prefix_attr_visible(), where $prefix_group_visible() just returns
true / false and $prefix_attr_visible() behaves as normal.

The motivation for this capability is to centralize PCI device
authentication in the PCI core with a named sysfs group while keeping
that group hidden for devices and platforms that do not meet the
requirements. In a PCI topology, most devices will not support
authentication, a small subset will support just PCI CMA (Component
Measurement and Authentication), a smaller subset will support PCI CMA +
PCIe IDE (Link Integrity and Encryption), and only next generation
server hosts will start to include a platform TSM (TEE Security
Manager).

Without this capability the alternatives are:

* Check if all attributes are invisible and if so, hide the directory.
Beyond trouble getting this to work [1], this is an ABI change for
scenarios if userspace happens to depend on group visibility absent any
attributes. I.e. this new capability avoids regression since it does
not retroactively apply to existing cases.

* Publish an empty /sys/bus/pci/devices/$pdev/tsm/ directory for all PCI
devices (i.e. for the case when TSM platform support is present, but
device support is absent). Unfortunate that this will be a vestigial
empty directory in the vast majority of cases.

* Reintroduce usage of runtime calls to sysfs_{create,remove}_group()
in the PCI core. Bjorn has already indicated that he does not want to
see any growth of pci_sysfs_init() [2].

* Drop the named group and simulate a directory by prefixing all
TSM-related attributes with "tsm_". Unfortunate to not use the naming
capability of a sysfs group as intended.

In comparison, there is a small potential for regression if for some
reason an @is_visible() callback had dependencies on how many times it
was called. Additionally, it is no longer an error to update a group
that does not have its directory already present, and it is no longer a
WARN() to remove a group that was never visible.

Link: https://lore.kernel.org/all/2024012321-envious-procedure-4a58@gregkh/ [1]
Link: https://lore.kernel.org/linux-pci/20231019200110.GA1410324@bhelgaas/ [2]
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/2024013028-deflator-flaring-ec62@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sysfs: Introduce a mechanism to hide static attribute_groups

Add a mechanism for named attribute_groups to hide their directory at
sysfs_update_group() time, or otherwise skip emitting the group
dir

sysfs: Introduce a mechanism to hide static attribute_groups

Add a mechanism for named attribute_groups to hide their directory at
sysfs_update_group() time, or otherwise skip emitting the group
directory when the group is first registered. It piggybacks on
is_visible() in a similar manner as SYSFS_PREALLOC, i.e. special flags
in the upper bits of the returned mode. To use it, specify a symbol
prefix to DEFINE_SYSFS_GROUP_VISIBLE(), and then pass that same prefix
to SYSFS_GROUP_VISIBLE() when assigning the @is_visible() callback:

DEFINE_SYSFS_GROUP_VISIBLE($prefix)

struct attribute_group $prefix_group = {
.name = $name,
.is_visible = SYSFS_GROUP_VISIBLE($prefix),
};

SYSFS_GROUP_VISIBLE() expects a definition of $prefix_group_visible()
and $prefix_attr_visible(), where $prefix_group_visible() just returns
true / false and $prefix_attr_visible() behaves as normal.

The motivation for this capability is to centralize PCI device
authentication in the PCI core with a named sysfs group while keeping
that group hidden for devices and platforms that do not meet the
requirements. In a PCI topology, most devices will not support
authentication, a small subset will support just PCI CMA (Component
Measurement and Authentication), a smaller subset will support PCI CMA +
PCIe IDE (Link Integrity and Encryption), and only next generation
server hosts will start to include a platform TSM (TEE Security
Manager).

Without this capability the alternatives are:

* Check if all attributes are invisible and if so, hide the directory.
Beyond trouble getting this to work [1], this is an ABI change for
scenarios if userspace happens to depend on group visibility absent any
attributes. I.e. this new capability avoids regression since it does
not retroactively apply to existing cases.

* Publish an empty /sys/bus/pci/devices/$pdev/tsm/ directory for all PCI
devices (i.e. for the case when TSM platform support is present, but
device support is absent). Unfortunate that this will be a vestigial
empty directory in the vast majority of cases.

* Reintroduce usage of runtime calls to sysfs_{create,remove}_group()
in the PCI core. Bjorn has already indicated that he does not want to
see any growth of pci_sysfs_init() [2].

* Drop the named group and simulate a directory by prefixing all
TSM-related attributes with "tsm_". Unfortunate to not use the naming
capability of a sysfs group as intended.

In comparison, there is a small potential for regression if for some
reason an @is_visible() callback had dependencies on how many times it
was called. Additionally, it is no longer an error to update a group
that does not have its directory already present, and it is no longer a
WARN() to remove a group that was never visible.

Link: https://lore.kernel.org/all/2024012321-envious-procedure-4a58@gregkh/ [1]
Link: https://lore.kernel.org/linux-pci/20231019200110.GA1410324@bhelgaas/ [2]
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/2024013028-deflator-flaring-ec62@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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kernfs: sysfs: support custom llseek method for sysfs entries

As of now, seeking in sysfs files is handled by generic_file_llseek().
There are situations where one may want to customize seeking logi

kernfs: sysfs: support custom llseek method for sysfs entries

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 636b21b50152 ("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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver-core: Introduce BIN_ATTR_ADMIN_{RO,RW}

Many binary attributes need to limit access to CAP_SYS_ADMIN only; ie
many binary attributes specify is_visible with 0400 or 0600.

Make setting the per

driver-core: Introduce BIN_ATTR_ADMIN_{RO,RW}

Many binary attributes need to limit access to CAP_SYS_ADMIN only; ie
many binary attributes specify is_visible with 0400 or 0600.

Make setting the permissions of such attributes more explicit by
defining BIN_ATTR_ADMIN_{RO,RW}.

Cc: Bjorn Helgaas <[email protected]>
Suggested-by: Dan Williams <[email protected]>
Suggested-by: Krzysztof Wilczyński <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ira Weiny <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dan Williams <[email protected]>

show more ...

sysfs: Rename struct bin_attribute member to f_mapping

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
latte

sysfs: Rename struct bin_attribute member to f_mapping

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 <[email protected]>
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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sysfs: Invoke iomem_get_mapping() from the sysfs open callback

Defer invocation of the iomem_get_mapping() to the sysfs open callback
so that it can be executed as needed when the binary sysfs objec

sysfs: Invoke iomem_get_mapping() from the sysfs open callback

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 <[email protected]>
Reviewed-by: Dan Williams <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sysfs: Add helper BIN_ATTRIBUTE_GROUPS

New helper BIN_ATTRIBUTE_GROUPS() does the same as ATTRIBUTE_GROUPS(),
just for binary attributes.

Signed-off-by: Heiner Kallweit <[email protected]>
Link:

sysfs: Add helper BIN_ATTRIBUTE_GROUPS

New helper BIN_ATTRIBUTE_GROUPS() does the same as ATTRIBUTE_GROUPS(),
just for binary attributes.

Signed-off-by: Heiner Kallweit <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

sysfs: Support zapping of binary attr mmaps

We want to be able to revoke pci mmaps so that the same access rules
applies as for /dev/kmem. Revoke support for devmem was added in
3234ac664a87 ("/dev/

sysfs: Support zapping of binary attr mmaps

We want to be able to revoke pci mmaps so that the same access rules
applies as for /dev/kmem. Revoke support for devmem was added in
3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims the
region").

The simplest way to achieve this is by having the same filp->f_mapping
for all mappings, so that unmap_mapping_range can find them all, no
matter through which file they've been created. Since this must be set
at open time we need sysfs support for this.

Add an optional mapping parameter bin_attr, which is only consulted
when there's also an mmap callback, since without mmap support
allowing to adjust the ->f_mapping makes no sense.

Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Bjorn Helgaas <[email protected]>
Cc: [email protected]
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Sourabh Jain <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Nayna Jain <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

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sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output

Output defects can exist in sysfs content using sprintf and snprintf.

sprintf does not know the PAGE_SIZE maximum of the temporary buf

sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output

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 <[email protected]>
Link: https://lore.kernel.org/r/884235202216d464d61ee975f7465332c86f76b2.1600285923.git.joe@perches.com
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW}

A common pattern for using plain DEVICE_ATTR() instead of
DEVICE_ATTR_RO() and DEVICE_ATTR_RW() is for attributes that want to
limit read to only roo

driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW}

A common pattern for using plain DEVICE_ATTR() instead of
DEVICE_ATTR_RO() and DEVICE_ATTR_RW() is for attributes that want to
limit read to only root. I.e. many users of DEVICE_ATTR() are
specifying 0400 or 0600 for permissions.

Given the expectation that CAP_SYS_ADMIN is needed to access these
sensitive attributes add an explicit helper with the _ADMIN_ identifier
for DEVICE_ATTR_ADMIN_{RO,RW}.

Cc: "Rafael J. Wysocki" <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Vishal Verma <[email protected]>

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driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW}

A common pattern for using plain DEVICE_ATTR() instead of
DEVICE_ATTR_RO() and DEVICE_ATTR_RW() is for attributes that want to
limit read to only roo

driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW}

A common pattern for using plain DEVICE_ATTR() instead of
DEVICE_ATTR_RO() and DEVICE_ATTR_RW() is for attributes that want to
limit read to only root. I.e. many users of DEVICE_ATTR() are
specifying 0400 or 0600 for permissions.

Given the expectation that CAP_SYS_ADMIN is needed to access these
sensitive attributes and an explicit helper with the _ADMIN_ identifier
for DEVICE_ATTR_ADMIN_{RO,RW}.

Cc: "Rafael J. Wysocki" <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Link: https://lore.kernel.org/r/159312906372.1850128.11611897078988158727.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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docs: filesystems: fix renamed references

Some filesystem references got broken by a previous patch
series I submitted. Address those.

Signed-off-by: Mauro Carvalho Chehab <[email protected]

docs: filesystems: fix renamed references

Some filesystem references got broken by a previous patch
series I submitted. Address those.

Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Acked-by: David Sterba <[email protected]> # fs/affs/Kconfig
Link: https://lore.kernel.org/r/57318c53008dbda7f6f4a5a9e5787f4d37e8565a.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <[email protected]>

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