drivers/xen/biomerge.c

Source file repositories/reference/linux-study-clean/drivers/xen/biomerge.c

File Facts

System
Linux kernel
Corpus path
drivers/xen/biomerge.c
Extension
.c
Size
617 bytes
Lines
24
Domain
Driver Families
Bucket
drivers/xen
Inferred role
Driver Families: implementation source
Status
source 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.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
#include <linux/bio.h>
#include <linux/export.h>
#include <xen/xen.h>
#include <xen/page.h>

/* check if @page can be merged with 'vec1' */
bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
			       const struct page *page)
{
#if XEN_PAGE_SIZE == PAGE_SIZE
	unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page));
	unsigned long bfn2 = pfn_to_bfn(page_to_pfn(page));

	return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2;
#else
	/*
	 * XXX: Add support for merging bio_vec when using different page
	 * size in Xen and Linux.
	 */
	return false;
#endif
}

Annotation

Implementation Notes