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xen/blkback: Shuffle code around (vbd_translate moved higher). 

We take out the chunk of code dealing with mapping to the guest
of pages into the xen_blk_map_buf code. And we also move the
vbd_translate to be done much earlier.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Konrad Rzeszutek Wilk 2011-04-15 11:35:13 -04:00
parent b0aef17924
commit 1a95fe6e42
1 changed files with 71 additions and 60 deletions
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131
drivers/xen/blkback/blkback.c
View File

@ -241,6 +241,10 @@ int blkif_schedule(void *arg)
return 0;
}
struct seg_buf {
unsigned long buf;
unsigned int nsec;
};
/*
* Unmap the grant references, and also remove the M2P over-rides
* used in the 'pending_req'.
@ -278,6 +282,62 @@ static void fast_flush_area(struct pending_req *req)
}
}
}
static int xen_blk_map_buf(struct blkif_request *req, struct pending_req *pending_req,
struct seg_buf seg[])
{
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
int i;
int nseg = req->nr_segments;
int ret = 0;
/* Fill out preq.nr_sects with proper amount of sectors, and setup
* assign map[..] with the PFN of the page in our domain with the
* corresponding grant reference for each page.
*/
for (i = 0; i < nseg; i++) {
uint32_t flags;
flags = GNTMAP_host_map;
if (pending_req->operation != BLKIF_OP_READ)
flags |= GNTMAP_readonly;
gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
req->u.rw.seg[i].gref, pending_req->blkif->domid);
}
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg);
BUG_ON(ret);
/* Now swizzel the MFN in our domain with the MFN from the other domain
* so that when we access vaddr(pending_req,i) it has the contents of
* the page from the other domain.
*/
for (i = 0; i < nseg; i++) {
if (unlikely(map[i].status != 0)) {
DPRINTK("invalid buffer -- could not remap it\n");
map[i].handle = BLKBACK_INVALID_HANDLE;
ret |= 1;
}
pending_handle(pending_req, i) = map[i].handle;
if (ret)
continue;
ret = m2p_add_override(PFN_DOWN(map[i].dev_bus_addr),
blkbk->pending_page(pending_req, i), false);
if (ret) {
printk(KERN_ALERT "Failed to install M2P override for"\
" %lx (ret: %d)\n", (unsigned long)
map[i].dev_bus_addr, ret);
/* We could switch over to GNTTABOP_copy */
continue;
}
seg[i].buf = map[i].dev_bus_addr |
(req->u.rw.seg[i].first_sect << 9);
}
return ret;
}
/*
* Completion callback on the bio's. Called as bh->b_end_io()
*/
@ -411,15 +471,12 @@ static void dispatch_rw_block_io(struct blkif_st *blkif,
struct blkif_request *req,
struct pending_req *pending_req)
{
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
struct phys_req preq;
struct {
unsigned long buf; unsigned int nsec;
} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
struct seg_buf seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
unsigned int nseg;
struct bio *bio = NULL;
struct bio *biolist[BLKIF_MAX_SEGMENTS_PER_REQUEST];
int ret, i, nbio = 0;
int i, nbio = 0;
int operation;
struct blk_plug plug;
struct request_queue *q;
@ -444,6 +501,7 @@ static void dispatch_rw_block_io(struct blkif_st *blkif,
if (unlikely(nseg == 0 && operation != WRITE_BARRIER) ||
unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
DPRINTK("Bad number of segments in request (%d)\n", nseg);
/* Haven't submitted any bio's yet. */
goto fail_response;
}
@ -456,76 +514,29 @@ static void dispatch_rw_block_io(struct blkif_st *blkif,
pending_req->operation = req->operation;
pending_req->status = BLKIF_RSP_OKAY;
pending_req->nr_pages = nseg;
/* Fill out preq.nr_sects with proper amount of sectors, and setup
* assign map[..] with the PFN of the page in our domain with the
* corresponding grant reference for each page.
*/
for (i = 0; i < nseg; i++) {
uint32_t flags;
seg[i].nsec = req->u.rw.seg[i].last_sect -
req->u.rw.seg[i].first_sect + 1;
if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) ||
(req->u.rw.seg[i].last_sect < req->u.rw.seg[i].first_sect))
goto fail_response;
preq.nr_sects += seg[i].nsec;
flags = GNTMAP_host_map;
if (operation != READ)
flags |= GNTMAP_readonly;
gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
req->u.rw.seg[i].gref, blkif->domid);
}
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg);
BUG_ON(ret);
/* Now swizzel the MFN in our domain with the MFN from the other domain
* so that when we access vaddr(pending_req,i) it has the contents of
* the page from the other domain.
*/
for (i = 0; i < nseg; i++) {
if (unlikely(map[i].status != 0)) {
DPRINTK("invalid buffer -- could not remap it\n");
map[i].handle = BLKBACK_INVALID_HANDLE;
ret |= 1;
}
pending_handle(pending_req, i) = map[i].handle;
if (ret)
continue;
ret = m2p_add_override(PFN_DOWN(map[i].dev_bus_addr),
blkbk->pending_page(pending_req, i), false);
if (ret) {
printk(KERN_ALERT "Failed to install M2P override for"\
" %lx (ret: %d)\n", (unsigned long)
map[i].dev_bus_addr, ret);
/* We could switch over to GNTTABOP_copy */
continue;
}
seg[i].buf = map[i].dev_bus_addr |
(req->u.rw.seg[i].first_sect << 9);
}
/* If we have failed at this point, we need to undo the M2P override,
* set gnttab_set_unmap_op on all of the grant references and perform
* the hypercall to unmap the grants - that is all done in
* fast_flush_area.
*/
if (ret)
goto fail_flush;
if (vbd_translate(&preq, blkif, operation) != 0) {
DPRINTK("access denied: %s of [%llu,%llu] on dev=%04x\n",
operation == READ ? "read" : "write",
preq.sector_number,
preq.sector_number + preq.nr_sects, preq.dev);
goto fail_flush;
goto fail_response;
}
/* If we have failed at this point, we need to undo the M2P override,
* set gnttab_set_unmap_op on all of the grant references and perform
* the hypercall to unmap the grants - that is all done in
* fast_flush_area.
*/
if (xen_blk_map_buf(req, pending_req, seg))
goto fail_flush;
/* This corresponding blkif_put is done in __end_block_io_op */
blkif_get(blkif);