kernel/drivers/misc/mei/dma-ring.c, branch linux-rolling-stable

mei: hook mei_device on class device

2025-09-06T17:50:54Z

mei_device lifetime was managed by devm procedure of parent device. But such memory is freed on device_del. Mei_device object is used by client object that may be alive after parent device is removed. It may lead to use-after-free if discrete graphics driver unloads mei_gsc auxiliary device while user-space holds open handle to mei character device. Connect mei_device structure lifteme to mei class device lifetime by adding mei_device free to class device remove callback. Move exising parent device pointer to separate field in mei_device to avoid misuse. Allocate character device dynamically and allow to control its own lifetime as it may outlive mei_device structure while character device closes after parent device is removed from the system. Leave power management on parent device as we overwrite pci runtime pm procedure and user-space is expecting it there. Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14201 Signed-off-by: Alexander Usyskin Link: https://lore.kernel.org/r/20250826125617.1166546-1-alexander.usyskin@intel.com Signed-off-by: Greg Kroah-Hartman

misc: mei: dma-ring.c: fix kernel-doc warnings

2023-10-18T08:01:33Z

Fix kernel-doc warnings in dma-ring.c: dma-ring.c:130: warning: No description found for return value of 'mei_dma_copy_from' dma-ring.c:150: warning: No description found for return value of 'mei_dma_copy_to' Signed-off-by: Randy Dunlap Cc: Tomas Winkler Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20231012024845.29169-4-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman

mei: docs: fix spelling errors

2023-10-18T08:01:33Z

Fix spelling errors in the mei code base. Signed-off-by: Tomas Winkler Reviewed-by: Randy Dunlap Link: https://lore.kernel.org/r/20231011074301.223879-4-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman

mei: adjust the copyright notice in the files.

2019-03-27T17:07:54Z

Use unified version of the copyright notice in the files Update copyright years according the year the files were touched, except this patch and SPDX conversions. Signed-off-by: Tomas Winkler Signed-off-by: Greg Kroah-Hartman

mei: dma ring: implement transmit flow

2018-11-26T15:59:48Z

Implement a circular buffer on allocated system memory. Read and write indices are stored on the control block which is also shared between the device and the host. Two new functions are exported from the DMA module: mei_dma_ring_write, and mei_dma_ring_empty_slots. The former simply copy a packet on the TX DMA circular buffer and later, returns the number of empty slots on the TX DMA circular buffer. Signed-off-by: Tomas Winkler Signed-off-by: Alexander Usyskin Signed-off-by: Greg Kroah-Hartman

mei: dma ring: implement rx circular buffer logic

2018-11-26T15:59:48Z

Implement circular buffer protocol over receive dma buffer. Add extension to the mei message header that holds length of the buffer on the dma buffer. Signed-off-by: Tomas Winkler Signed-off-by: Alexander Usyskin Signed-off-by: Greg Kroah-Hartman

mei: hw: add dma ring control block

2018-11-26T15:59:48Z

The DMA ring control block contains write and read indices for host and device circular buffers. Signed-off-by: Tomas Winkler Signed-off-by: Alexander Usyskin Signed-off-by: Greg Kroah-Hartman

mei: dma ring buffers allocation

2018-11-26T15:59:48Z

Allocate DMA ring buffers from managed coherent memory. Signed-off-by: Tomas Winkler Signed-off-by: Alexander Usyskin Signed-off-by: Greg Kroah-Hartman