From 1a95fe6e42cefc52c62c471ad87d7fe8643231df Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 15 Apr 2011 11:35:13 -0400 Subject: [PATCH] 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 --- drivers/xen/blkback/blkback.c | 129 ++++++++++++++++++---------------- 1 file changed, 70 insertions(+), 59 deletions(-) diff --git a/drivers/xen/blkback/blkback.c b/drivers/xen/blkback/blkback.c index f282463d7b5c..211b2005f963 100644 --- a/drivers/xen/blkback/blkback.c +++ b/drivers/xen/blkback/blkback.c @@ -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; } @@ -456,77 +514,30 @@ 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 (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_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 (ret) + if (xen_blk_map_buf(req, pending_req, seg)) 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; - } - /* This corresponding blkif_put is done in __end_block_io_op */ blkif_get(blkif); -- 2.34.1