Align struct file_operations with upstream v6.14 #311
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Chapter 6, "Character Device Drivers", section 6.1 still showed the v5.4 layout of 'struct file_operations'. Replace it with the version shipped in upstream Linux v6.14, keeping the example buildable and the API in step with modern kernels. Co-authored-by: EricccTaiwan <[email protected]>
| @@ -908,46 +908,52 @@ \subsection{The file\_operations Structure} | |||
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| For example, every character driver needs to define a function that reads from the device. | |||
| The \cpp|file_operations| structure holds the address of the module's function that performs that operation. | |||
| Here is what the definition looks like for kernel 5.4: | |||
| Here is what the definition looks like for kernel 6.14: | |||
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Don't do that. Linux v5.4 is a long-term support kernel. LKMPG maintains compatibility with LTS kernels, which means all content should be compatible with Linux v5.4 and newer versions, rather than focusing exclusively on recent Linux releases. Instead of modifying the struct definitions, please document any changes to member fields in the descriptions.
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Thanks for your clarification! That make sense.
I just want to confirm that my understanding aligns with your intent:
I’ll revert the struct file_operations example to the original Linux 5.4 definition (undoing my earlier changes) so it stays compatible with all LTS kernels.
To cover newer kernels without breaking the build, I’ll add a short note right after the code that lists the fields added, removed, or modified since 5.4.
As of Linux kernel 6.12, several member fields have been added or removed, or had their prototypes changed:
- Added:
fop_flags,splice_eof,uring_cmd,uring_cmd_iopoll,mmap_capabilities- Removed:
iterate,sendpage,mmap_supported_flags(!CONFIG_MMU)- Modified:
iopollnow takesstruct io_comp_batch *andunsigned int flagssetleasenow usesstruct file_lease **andintinstead oflong
Let me know if this approach fits the documentation style you prefer, or if you'd suggest any adjustments.
Chapter 6, "Character Device Drivers", section 6.1 still showed the v5.4 layout of 'struct file_operations'. Replace it with the version shipped in upstream Linux v6.14, keeping the example buildable and the API in step with modern kernels.
Upstream reference: https://elixir.bootlin.com/linux/v6.14/source/include/linux/fs.h#L2131
Summary by Bito
This pull request updates the 'struct file_operations' documentation to align with Linux kernel version 6.14, replacing the outdated reference to version 5.4. Enhancements include modifications to function pointers and the addition of new fields, improving API clarity for character device driver developers.Unit tests added: False
Estimated effort to review (1-5, lower is better): 2