diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/xen-blkback/blkback.c | 169 | ||||
| -rw-r--r-- | drivers/block/xen-blkback/common.h | 3 |
2 files changed, 122 insertions, 50 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 908e630240bd..2a04d341e598 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -47,6 +47,7 @@ #include <asm/xen/hypervisor.h> #include <asm/xen/hypercall.h> #include <xen/balloon.h> +#include <xen/grant_table.h> #include "common.h" /* @@ -262,6 +263,17 @@ static void put_persistent_gnt(struct xen_blkif *blkif, atomic_dec(&blkif->persistent_gnt_in_use); } +static void free_persistent_gnts_unmap_callback(int result, + struct gntab_unmap_queue_data *data) +{ + struct completion *c = data->data; + + /* BUG_ON used to reproduce existing behaviour, + but is this the best way to deal with this? */ + BUG_ON(result); + complete(c); +} + static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, unsigned int num) { @@ -269,8 +281,17 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; struct persistent_gnt *persistent_gnt; struct rb_node *n; - int ret = 0; int segs_to_unmap = 0; + struct gntab_unmap_queue_data unmap_data; + struct completion unmap_completion; + + init_completion(&unmap_completion); + + unmap_data.data = &unmap_completion; + unmap_data.done = &free_persistent_gnts_unmap_callback; + unmap_data.pages = pages; + unmap_data.unmap_ops = unmap; + unmap_data.kunmap_ops = NULL; foreach_grant_safe(persistent_gnt, n, root, node) { BUG_ON(persistent_gnt->handle == @@ -285,9 +306,11 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST || !rb_next(&persistent_gnt->node)) { - ret = gnttab_unmap_refs(unmap, NULL, pages, - segs_to_unmap); - BUG_ON(ret); + + unmap_data.count = segs_to_unmap; + gnttab_unmap_refs_async(&unmap_data); + wait_for_completion(&unmap_completion); + put_free_pages(blkif, pages, segs_to_unmap); segs_to_unmap = 0; } @@ -653,18 +676,14 @@ void xen_blkbk_free_caches(struct xen_blkif *blkif) shrink_free_pagepool(blkif, 0 /* All */); } -/* - * Unmap the grant references, and also remove the M2P over-rides - * used in the 'pending_req'. - */ -static void xen_blkbk_unmap(struct xen_blkif *blkif, - struct grant_page *pages[], - int num) +static unsigned int xen_blkbk_unmap_prepare( + struct xen_blkif *blkif, + struct grant_page **pages, + unsigned int num, + struct gnttab_unmap_grant_ref *unmap_ops, + struct page **unmap_pages) { - struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; - struct page *unmap_pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; unsigned int i, invcount = 0; - int ret; for (i = 0; i < num; i++) { if (pages[i]->persistent_gnt != NULL) { @@ -674,21 +693,95 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif, if (pages[i]->handle == BLKBACK_INVALID_HANDLE) continue; unmap_pages[invcount] = pages[i]->page; - gnttab_set_unmap_op(&unmap[invcount], vaddr(pages[i]->page), + gnttab_set_unmap_op(&unmap_ops[invcount], vaddr(pages[i]->page), GNTMAP_host_map, pages[i]->handle); pages[i]->handle = BLKBACK_INVALID_HANDLE; - if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) { - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, - invcount); + invcount++; + } + + return invcount; +} + +static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_queue_data *data) +{ + struct pending_req* pending_req = (struct pending_req*) (data->data); + struct xen_blkif *blkif = pending_req->blkif; + + /* BUG_ON used to reproduce existing behaviour, + but is this the best way to deal with this? */ + BUG_ON(result); + + put_free_pages(blkif, data->pages, data->count); + make_response(blkif, pending_req->id, + pending_req->operation, pending_req->status); + free_req(blkif, pending_req); + /* + * Make sure the request is freed before releasing blkif, + * or there could be a race between free_req and the + * cleanup done in xen_blkif_free during shutdown. + * + * NB: The fact that we might try to wake up pending_free_wq + * before drain_complete (in case there's a drain going on) + * it's not a problem with our current implementation + * because we can assure there's no thread waiting on + * pending_free_wq if there's a drain going on, but it has + * to be taken into account if the current model is changed. + */ + if (atomic_dec_and_test(&blkif->inflight) && atomic_read(&blkif->drain)) { + complete(&blkif->drain_complete); + } + xen_blkif_put(blkif); +} + +static void xen_blkbk_unmap_and_respond(struct pending_req *req) +{ + struct gntab_unmap_queue_data* work = &req->gnttab_unmap_data; + struct xen_blkif *blkif = req->blkif; + struct grant_page **pages = req->segments; + unsigned int invcount; + + invcount = xen_blkbk_unmap_prepare(blkif, pages, req->nr_pages, + req->unmap, req->unmap_pages); + + work->data = req; + work->done = xen_blkbk_unmap_and_respond_callback; + work->unmap_ops = req->unmap; + work->kunmap_ops = NULL; + work->pages = req->unmap_pages; + work->count = invcount; + + gnttab_unmap_refs_async(&req->gnttab_unmap_data); +} + + +/* + * Unmap the grant references. + * + * This could accumulate ops up to the batch size to reduce the number + * of hypercalls, but since this is only used in error paths there's + * no real need. + */ +static void xen_blkbk_unmap(struct xen_blkif *blkif, + struct grant_page *pages[], + int num) +{ + struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + struct page *unmap_pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + unsigned int invcount = 0; + int ret; + + while (num) { + unsigned int batch = min(num, BLKIF_MAX_SEGMENTS_PER_REQUEST); + + invcount = xen_blkbk_unmap_prepare(blkif, pages, batch, + unmap, unmap_pages); + if (invcount) { + ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount); BUG_ON(ret); put_free_pages(blkif, unmap_pages, invcount); - invcount = 0; } - } - if (invcount) { - ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount); - BUG_ON(ret); - put_free_pages(blkif, unmap_pages, invcount); + pages += batch; + num -= batch; } } @@ -982,32 +1075,8 @@ static void __end_block_io_op(struct pending_req *pending_req, int error) * the grant references associated with 'request' and provide * the proper response on the ring. */ - if (atomic_dec_and_test(&pending_req->pendcnt)) { - struct xen_blkif *blkif = pending_req->blkif; - - xen_blkbk_unmap(blkif, - pending_req->segments, - pending_req->nr_pages); - make_response(blkif, pending_req->id, - pending_req->operation, pending_req->status); - free_req(blkif, pending_req); - /* - * Make sure the request is freed before releasing blkif, - * or there could be a race between free_req and the - * cleanup done in xen_blkif_free during shutdown. - * - * NB: The fact that we might try to wake up pending_free_wq - * before drain_complete (in case there's a drain going on) - * it's not a problem with our current implementation - * because we can assure there's no thread waiting on - * pending_free_wq if there's a drain going on, but it has - * to be taken into account if the current model is changed. - */ - if (atomic_dec_and_test(&blkif->inflight) && atomic_read(&blkif->drain)) { - complete(&blkif->drain_complete); - } - xen_blkif_put(blkif); - } + if (atomic_dec_and_test(&pending_req->pendcnt)) + xen_blkbk_unmap_and_respond(pending_req); } /* diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index f65b807e3236..cc90a840e616 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -350,6 +350,9 @@ struct pending_req { struct grant_page *indirect_pages[MAX_INDIRECT_PAGES]; struct seg_buf seg[MAX_INDIRECT_SEGMENTS]; struct bio *biolist[MAX_INDIRECT_SEGMENTS]; + struct gnttab_unmap_grant_ref unmap[MAX_INDIRECT_SEGMENTS]; + struct page *unmap_pages[MAX_INDIRECT_SEGMENTS]; + struct gntab_unmap_queue_data gnttab_unmap_data; }; |