drivers/s390/block/dcssblk.c

File Facts

System

Linux kernel

Corpus path

drivers/s390/block/dcssblk.c

Extension

.c

Size

26773 bytes

Lines

1055

Domain

Driver Families

Bucket

drivers/s390

Inferred role

Driver Families: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/module.h
• linux/moduleparam.h
• linux/ctype.h
• linux/errno.h
• linux/init.h
• linux/slab.h
• linux/blkdev.h
• linux/completion.h
• linux/interrupt.h
• linux/uio.h
• linux/dax.h
• linux/io.h
• asm/extmem.h

Detected Declarations

• struct dcssblk_dev_info
• struct segment_info
• function dcssblk_dax_zero_page_range
• function dcssblk_release_segment
• function down_write
• function down_read
• function list_for_each_entry
• function down_read
• function list_for_each_entry
• function dcssblk_find_highest_addr
• function dcssblk_find_lowest_addr
• function dcssblk_is_continuous
• function dcssblk_load_segment
• function operation
• function dcssblk_shared_store
• function list_for_each_entry
• function list_for_each_entry
• function dcssblk_save_show
• function dcssblk_save_store
• function list_for_each_entry
• function dcssblk_seglist_show
• function dcssblk_setup_dax
• function dcssblk_add_store
• function dcssblk_remove_store
• function dcssblk_open
• function dcssblk_release
• function list_for_each_entry
• function dcssblk_submit_bio
• function __dcssblk_direct_access
• function dcssblk_dax_direct_access
• function dcssblk_check_params
• function dcssblk_exit
• function dcssblk_init
• module init dcssblk_init

Annotated Snippet

module_init(dcssblk_init);
module_exit(dcssblk_exit);

module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
		 "comma-separated list, names in each set separated "
		 "by commas are separated by colons, each set contains "
		 "names of contiguous segments and each name max. 8 chars.\n"
		 "Adding \"(local)\" to the end of each set equals echoing 0 "
		 "to /sys/devices/dcssblk/<device name>/shared after loading "
		 "the contiguous segments - \n"
		 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");

MODULE_DESCRIPTION("S/390 block driver for DCSS memory");
MODULE_LICENSE("GPL");

Annotation

• Immediate include surface: `linux/module.h`, `linux/moduleparam.h`, `linux/ctype.h`, `linux/errno.h`, `linux/init.h`, `linux/slab.h`, `linux/blkdev.h`, `linux/completion.h`.
• Detected declarations: `struct dcssblk_dev_info`, `struct segment_info`, `function dcssblk_dax_zero_page_range`, `function dcssblk_release_segment`, `function down_write`, `function down_read`, `function list_for_each_entry`, `function down_read`, `function list_for_each_entry`, `function dcssblk_find_highest_addr`.
• Atlas domain: Driver Families / drivers/s390.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.