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path: root/drivers/block/xen-blkback/blkback.c
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Diffstat (limited to 'drivers/block/xen-blkback/blkback.c')
-rw-r--r--drivers/block/xen-blkback/blkback.c81
1 files changed, 52 insertions, 29 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index da18046d0e07..64c60edcdfbc 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -285,7 +285,8 @@ 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, pages, segs_to_unmap);
+ ret = gnttab_unmap_refs(unmap, NULL, pages,
+ segs_to_unmap);
BUG_ON(ret);
put_free_pages(blkif, pages, segs_to_unmap);
segs_to_unmap = 0;
@@ -298,7 +299,7 @@ static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root,
BUG_ON(num != 0);
}
-static void unmap_purged_grants(struct work_struct *work)
+void xen_blkbk_unmap_purged_grants(struct work_struct *work)
{
struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
@@ -320,7 +321,8 @@ static void unmap_purged_grants(struct work_struct *work)
pages[segs_to_unmap] = persistent_gnt->page;
if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
- ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
+ ret = gnttab_unmap_refs(unmap, NULL, pages,
+ segs_to_unmap);
BUG_ON(ret);
put_free_pages(blkif, pages, segs_to_unmap);
segs_to_unmap = 0;
@@ -328,7 +330,7 @@ static void unmap_purged_grants(struct work_struct *work)
kfree(persistent_gnt);
}
if (segs_to_unmap > 0) {
- ret = gnttab_unmap_refs(unmap, pages, segs_to_unmap);
+ ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap);
BUG_ON(ret);
put_free_pages(blkif, pages, segs_to_unmap);
}
@@ -373,7 +375,7 @@ static void purge_persistent_gnt(struct xen_blkif *blkif)
pr_debug(DRV_PFX "Going to purge %u persistent grants\n", num_clean);
- INIT_LIST_HEAD(&blkif->persistent_purge_list);
+ BUG_ON(!list_empty(&blkif->persistent_purge_list));
root = &blkif->persistent_gnts;
purge_list:
foreach_grant_safe(persistent_gnt, n, root, node) {
@@ -418,7 +420,6 @@ finished:
blkif->vbd.overflow_max_grants = 0;
/* We can defer this work */
- INIT_WORK(&blkif->persistent_purge_work, unmap_purged_grants);
schedule_work(&blkif->persistent_purge_work);
pr_debug(DRV_PFX "Purged %u/%u\n", (total - num_clean), total);
return;
@@ -623,9 +624,23 @@ purge_gnt_list:
print_stats(blkif);
}
- /* Since we are shutting down remove all pages from the buffer */
- shrink_free_pagepool(blkif, 0 /* All */);
+ /* Drain pending purge work */
+ flush_work(&blkif->persistent_purge_work);
+ if (log_stats)
+ print_stats(blkif);
+
+ blkif->xenblkd = NULL;
+ xen_blkif_put(blkif);
+
+ return 0;
+}
+
+/*
+ * Remove persistent grants and empty the pool of free pages
+ */
+void xen_blkbk_free_caches(struct xen_blkif *blkif)
+{
/* Free all persistent grant pages */
if (!RB_EMPTY_ROOT(&blkif->persistent_gnts))
free_persistent_gnts(blkif, &blkif->persistent_gnts,
@@ -634,13 +649,8 @@ purge_gnt_list:
BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
blkif->persistent_gnt_c = 0;
- if (log_stats)
- print_stats(blkif);
-
- blkif->xenblkd = NULL;
- xen_blkif_put(blkif);
-
- return 0;
+ /* Since we are shutting down remove all pages from the buffer */
+ shrink_free_pagepool(blkif, 0 /* All */);
}
/*
@@ -668,14 +678,15 @@ static void xen_blkbk_unmap(struct xen_blkif *blkif,
GNTMAP_host_map, pages[i]->handle);
pages[i]->handle = BLKBACK_INVALID_HANDLE;
if (++invcount == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
- ret = gnttab_unmap_refs(unmap, unmap_pages, 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, unmap_pages, invcount);
+ ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
BUG_ON(ret);
put_free_pages(blkif, unmap_pages, invcount);
}
@@ -737,7 +748,7 @@ again:
}
if (segs_to_map) {
- ret = gnttab_map_refs(map, pages_to_gnt, segs_to_map);
+ ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
BUG_ON(ret);
}
@@ -835,7 +846,7 @@ static int xen_blkbk_parse_indirect(struct blkif_request *req,
struct grant_page **pages = pending_req->indirect_pages;
struct xen_blkif *blkif = pending_req->blkif;
int indirect_grefs, rc, n, nseg, i;
- struct blkif_request_segment_aligned *segments = NULL;
+ struct blkif_request_segment *segments = NULL;
nseg = pending_req->nr_pages;
indirect_grefs = INDIRECT_PAGES(nseg);
@@ -931,9 +942,7 @@ static void xen_blk_drain_io(struct xen_blkif *blkif)
{
atomic_set(&blkif->drain, 1);
do {
- /* The initial value is one, and one refcnt taken at the
- * start of the xen_blkif_schedule thread. */
- if (atomic_read(&blkif->refcnt) <= 2)
+ if (atomic_read(&blkif->inflight) == 0)
break;
wait_for_completion_interruptible_timeout(
&blkif->drain_complete, HZ);
@@ -973,17 +982,30 @@ static void __end_block_io_op(struct pending_req *pending_req, int error)
* the proper response on the ring.
*/
if (atomic_dec_and_test(&pending_req->pendcnt)) {
- xen_blkbk_unmap(pending_req->blkif,
+ struct xen_blkif *blkif = pending_req->blkif;
+
+ xen_blkbk_unmap(blkif,
pending_req->segments,
pending_req->nr_pages);
- make_response(pending_req->blkif, pending_req->id,
+ make_response(blkif, pending_req->id,
pending_req->operation, pending_req->status);
- xen_blkif_put(pending_req->blkif);
- if (atomic_read(&pending_req->blkif->refcnt) <= 2) {
- if (atomic_read(&pending_req->blkif->drain))
- complete(&pending_req->blkif->drain_complete);
+ 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);
}
- free_req(pending_req->blkif, pending_req);
+ xen_blkif_put(blkif);
}
}
@@ -1237,6 +1259,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
* below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
*/
xen_blkif_get(blkif);
+ atomic_inc(&blkif->inflight);
for (i = 0; i < nseg; i++) {
while ((bio == NULL) ||
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-10 23:57:05 +0000