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Commit efe08a3e authored by Jan Beulich's avatar Jan Beulich Committed by Konrad Rzeszutek Wilk
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xen/blkback: simplify address translations 



Cherry-pick and modified from 69d64727c42eecd47fdf82c15a54474d21a4012a
("blkback/blktap2: simplify address translations"):

"There are quite a number of places where e.g. page->va->page
translations happen.

Besides yielding smaller code (source and binary), a second goal is to
make it easier to determine where virtual addresses of pages allocated
through alloc_empty_pages_and_pagevec() are really used (in turn in
order to determine whether using highmem pages would be possible
there)."

The second goal is not the purpose of this patch - it is just to
make it easier to read the code.

linux-2.6-pvops:
 * Stripped drivers/xen/gntdev/*
 * Stripped drivers/xen/netback/*

[v2: Stripped blktap off]

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarDaniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent bc0c081b

drivers/xen/blkback/blkback.c

+6 −4
Original line number Diff line number Diff line
@@ -99,9 +99,11 @@ static inline int vaddr_pagenr(pending_req_t *req, int seg) 
	return (req - pending_reqs) * BLKIF_MAX_SEGMENTS_PER_REQUEST + seg;

}



#define pending_page(req, seg) pending_pages[vaddr_pagenr(req, seg)]



static inline unsigned long vaddr(pending_req_t *req, int seg)

{

	unsigned long pfn = page_to_pfn(pending_pages[vaddr_pagenr(req, seg)]);

	unsigned long pfn = page_to_pfn(pending_page(req, seg));

	return (unsigned long)pfn_to_kaddr(pfn);

}
@@ -463,8 +465,8 @@ static void dispatch_rw_block_io(blkif_t *blkif, 
		if (ret)

			continue;



		set_phys_to_machine(__pa(vaddr(

			pending_req, i)) >> PAGE_SHIFT,

		set_phys_to_machine(

			page_to_pfn(pending_page(pending_req, i)),

			FOREIGN_FRAME(map[i].dev_bus_addr >> PAGE_SHIFT));

		seg[i].buf  = map[i].dev_bus_addr |

			(req->seg[i].first_sect << 9);
@@ -495,7 +497,7 @@ static void dispatch_rw_block_io(blkif_t *blkif, 


		while ((bio == NULL) ||

		       (bio_add_page(bio,

				     virt_to_page(vaddr(pending_req, i)),

				     pending_page(pending_req, i),

				     seg[i].nsec << 9,

				     seg[i].buf & ~PAGE_MASK) == 0)) {

			if (bio) {