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-rw-r--r--drivers/block/xen-blkback/blkback.c169
-rw-r--r--drivers/block/xen-blkback/common.h3
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;
};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 23:16:31 +0000