kernel/dma/coherent.c

File Facts

System

Linux kernel

Corpus path

kernel/dma/coherent.c

Extension

.c

Size

11500 bytes

Lines

411

Domain

Core OS

Bucket

Scheduler, Processes, Timers, Sync, And Syscalls

Inferred role

Core OS: exported/initcall integration point

Status

integration implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• 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.
• Touches IRQ or DMA behavior; this matters for the representative real-device path.
• 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/io.h
• linux/slab.h
• linux/kernel.h
• linux/module.h
• linux/dma-direct.h
• linux/dma-map-ops.h
• linux/of.h
• linux/of_fdt.h
• linux/of_reserved_mem.h

Detected Declarations

• struct dma_coherent_mem
• function dma_get_device_base
• function _dma_release_coherent_memory
• function dma_assign_coherent_memory
• function dma_alloc_coherent
• function dma_release_coherent_memory
• function dma_alloc_from_dev_coherent
• function __dma_release_from_coherent
• function dma_release_from_dev_coherent
• function __dma_mmap_from_coherent
• function dma_mmap_from_dev_coherent
• function dma_release_from_global_coherent
• function dma_mmap_from_global_coherent
• function dma_init_global_coherent
• function rmem_dma_device_init
• function rmem_dma_device_release
• function rmem_dma_setup
• function dma_init_reserved_memory
• module init dma_init_reserved_memory

Annotated Snippet

core_initcall(dma_init_reserved_memory);
#endif /* CONFIG_DMA_GLOBAL_POOL */

static const struct reserved_mem_ops rmem_dma_ops = {
	.node_init	= rmem_dma_setup,
	.device_init	= rmem_dma_device_init,
	.device_release	= rmem_dma_device_release,
};

RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", &rmem_dma_ops);
#endif

Annotation

• Immediate include surface: `linux/io.h`, `linux/slab.h`, `linux/kernel.h`, `linux/module.h`, `linux/dma-direct.h`, `linux/dma-map-ops.h`, `linux/of.h`, `linux/of_fdt.h`.
• Detected declarations: `struct dma_coherent_mem`, `function dma_get_device_base`, `function _dma_release_coherent_memory`, `function dma_assign_coherent_memory`, `function dma_alloc_coherent`, `function dma_release_coherent_memory`, `function dma_alloc_from_dev_coherent`, `function __dma_release_from_coherent`, `function dma_release_from_dev_coherent`, `function __dma_mmap_from_coherent`.
• Atlas domain: Core OS / Scheduler, Processes, Timers, Sync, And Syscalls.
• Implementation status: integration implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.
• IRQ or DMA behavior appears here, which is relevant to the selected PCIe/NVMe device path.

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.