linedisp_release() currently retrieves the enclosing struct linedisp via
to_linedisp(). That lookup depends on the attachment list, but the
attachment may already have been removed before put_device() invokes the
release callback. This can happen in linedisp_unregister(), and can also
be reached from some linedisp_register() error paths.
In that case, to_linedisp() returns NULL and linedisp_release()
dereferences it while freeing the display resources.
The struct device released here is the embedded linedisp->dev used by
linedisp_register(), so retrieve the enclosing object directly with
container_of() instead.
Fixes: 66c9380948 ("auxdisplay: linedisp: encapsulate container_of usage within to_linedisp")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
Enable linedisp library integration into existing kernel devices (like LED
class) to provide a uniform 7-segment userspace API without creating
separate child devices, meeting the consistent interface while maintaining
coherent device hierarchies.
This allows uniform 7-segment API across all drivers while solving device
proliferation and fragmented userspace interfaces.
The sysfs attributes appear in one of the two locations depending on usage:
1. On linedisp.N child devices (legacy linedisp_register())
2. On the parent auxdisplay device (new linedisp_attach())
Functionality is identical in both modes.
Existing consumers of linedisp_register() are unaffected. The new API
enables drivers like TM16XX to integrate 7-segment display functionality
seamlessly within their LED class device hierarchy.
Signed-off-by: Jean-François Lessard <jefflessard3@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Add a read-only 'num_chars' sysfs attribute to report display digit count.
The num_chars attribute provides essential capability information to
userspace applications that need to know display dimensions before writing
messages, complementing the existing message and scroll controls.
No functional changes to existing behavior.
Signed-off-by: Jean-François Lessard <jefflessard3@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Currently, when a message shorter than the display size is written, the
content wraps around (e.g., "123" on a 4-digit display shows "1231")
without scrolling, which is confusing and unintuitive.
Change behavior to display short messages statically with space padding
(e.g. "123 ") while only scrolling messages longer than the display width.
This provides more natural behavior that aligns with user expectations
and current linedisp_display() kernel-doc.
The scroll logic is also consolidated into a helper function for clarity.
No API changes are introduced.
Signed-off-by: Jean-François Lessard <jefflessard3@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Replace direct container_of() calls with a to_linedisp() helper function
throughout the line-display auxdisplay library module. This abstraction
prepares for upcoming dual-mode support where linedisp context retrieval
will need to handle both dedicated child devices and attached parent
auxdisplay devices.
No functional changes in this patch.
Signed-off-by: Jean-François Lessard <jefflessard3@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree
over and remove the historical wrapper inlines.
Conversion was done with coccinelle plus manual fixups where necessary.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/auxdisplay/line-display.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
There is already the driver using character mapping table for
7 or 14 segment display. It is possible to override it. Make
the similar in the line display library to allow other drivers
to utilise the same functionality.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Currently the line display library doesn't scale in case we want to
provide more operations. Prepare the library to take a newly created
struct linedisp_ops that scales.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Do not imply that some of the generic headers may be always included.
Instead, include explicitly what we are direct user of.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
kstrtox() may return different error codes.
Unshadow them in the ->store() callback to give better error report.
While at it, add missing kstrtox.h inclusion.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
The absence of decrementation of linedisp_id is incorrect in two ways,
i.e. it may cause:
- an ID exhaustion
- (and if the above is addressed) a duplicate id number may be allocated
next time a device is added
Replace above mentioned approach by using IDA framework.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
While there is no issue currently with the resources allocation,
the code may still be made more robust by deallocating message
in the ->release() callback.
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
If the message to display is longer than the number of characters that
the display can show, the message will be scrolled. Currently the
scroll rate is fixed, moving every 500 ms.
Add support for changing the scroll rate through a "scroll_step_ms"
device attribute in sysfs.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Use the existing kmemdup_nul() helper instead of open-coding the same
operation.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Extract the character line display core support from the simple ASCII
LCD driver for the MIPS Boston, Malta & SEAD3 development boards into
its own subdriver, so it can be reused for other displays.
As this moves the "message" device attribute in sysfs in a "linedisp.N"
subdirectory, a symlink is added to preserve backwards compatibility.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
