drivers/scsi/ch.c

File Facts

System

Linux kernel

Corpus path

drivers/scsi/ch.c

Extension

.c

Size

25534 bytes

Lines

1038

Domain

Driver Families

Bucket

drivers/scsi

Inferred role

Driver Families: operation-table or driver-model contract

Status

pattern 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.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• 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/init.h
• linux/fs.h
• linux/kernel.h
• linux/mm.h
• linux/major.h
• linux/string.h
• linux/errno.h
• linux/interrupt.h
• linux/blkdev.h
• linux/completion.h
• linux/compat.h
• linux/chio.h
• linux/mutex.h
• linux/idr.h
• linux/slab.h
• scsi/scsi.h
• scsi/scsi_cmnd.h
• scsi/scsi_driver.h
• scsi/scsi_ioctl.h
• scsi/scsi_host.h
• scsi/scsi_device.h
• scsi/scsi_eh.h
• scsi/scsi_dbg.h

Detected Declarations

• struct changer_element_status32
• function ch_find_errno
• function ch_do_scsi
• function ch_elem_to_typecode
• function ch_read_element_status
• function ch_init_elem
• function ch_readconfig
• function ch_position
• function ch_move
• function ch_exchange
• function ch_check_voltag
• function ch_set_voltag
• function ch_gstatus
• function ch_destroy
• function ch_release
• function ch_open
• function ch_checkrange
• function ch_ioctl
• function ch_probe
• function ch_remove
• function init_ch_module
• function exit_ch_module
• module init init_ch_module

Annotated Snippet

static const struct file_operations changer_fops = {
	.owner		= THIS_MODULE,
	.open		= ch_open,
	.release	= ch_release,
	.unlocked_ioctl	= ch_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
	.llseek		= noop_llseek,
};

static int __init init_ch_module(void)
{
	int rc;

	printk(KERN_INFO "SCSI Media Changer driver v" VERSION " \n");
	rc = class_register(&ch_sysfs_class);
	if (rc)
		return rc;
	rc = register_chrdev(SCSI_CHANGER_MAJOR,"ch",&changer_fops);
	if (rc < 0) {
		printk("Unable to get major %d for SCSI-Changer\n",
		       SCSI_CHANGER_MAJOR);
		goto fail1;
	}
	rc = scsi_register_driver(&ch_template);
	if (rc < 0)
		goto fail2;
	return 0;

 fail2:
	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
 fail1:
	class_unregister(&ch_sysfs_class);
	return rc;
}

static void __exit exit_ch_module(void)
{
	scsi_unregister_driver(&ch_template);
	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
	class_unregister(&ch_sysfs_class);
	idr_destroy(&ch_index_idr);
}

module_init(init_ch_module);
module_exit(exit_ch_module);

Annotation

• Immediate include surface: `linux/module.h`, `linux/init.h`, `linux/fs.h`, `linux/kernel.h`, `linux/mm.h`, `linux/major.h`, `linux/string.h`, `linux/errno.h`.
• Detected declarations: `struct changer_element_status32`, `function ch_find_errno`, `function ch_do_scsi`, `function ch_elem_to_typecode`, `function ch_read_element_status`, `function ch_init_elem`, `function ch_readconfig`, `function ch_position`, `function ch_move`, `function ch_exchange`.
• Atlas domain: Driver Families / drivers/scsi.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.
• 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.