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authorJens Axboe <axboe@fb.com>2014-02-10 12:52:34 -0700
committerJens Axboe <axboe@fb.com>2014-02-10 12:52:34 -0700
commit9d4cb8e3a5b448d802155688bf2d50ac1b9e1a51 (patch)
tree95f3ee193b9f6a248001cee13e1f4ea23704ca45 /drivers/block/xen-blkback
parent11c94444074f40b479a05f6657d935204e992f2e (diff)
parent3661371701e714f0cea4120f6a365340858fb4e4 (diff)
Merge branch 'stable/for-jens-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip into for-linus
Konrad writes: Please git pull the following branch: git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip.git stable/for-jens-3.14 which is based off v3.13-rc6. If you would like me to rebase it on a different branch/tag I would be more than happy to do so. The patches are all bug-fixes and hopefully can go in 3.14. They deal with xen-blkback shutdown and cause memory leaks as well as shutdown races. They should go to stable tree and if you are OK with I will ask them to backport those fixes. There is also a fix to xen-blkfront to deal with unexpected state transition. And lastly a fix to the header where it was using the __aligned__ unnecessarily.
Diffstat (limited to 'drivers/block/xen-blkback')
-rw-r--r--drivers/block/xen-blkback/blkback.c63
-rw-r--r--drivers/block/xen-blkback/common.h4
-rw-r--r--drivers/block/xen-blkback/xenbus.c13
3 files changed, 58 insertions, 22 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 4b97b86da926..765fc7348b66 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -375,7 +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) {
@@ -625,9 +625,23 @@ 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,
@@ -636,13 +650,8 @@ 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 */);
}
/*
@@ -838,7 +847,7 @@ 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);
@@ -934,9 +943,7 @@ 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);
@@ -976,17 +983,30 @@ 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);
}
}
@@ -1240,6 +1260,7 @@ 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) ||
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index 8d8807563d99..9eb34e24b4fe 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -57,7 +57,7 @@
#define MAX_INDIRECT_SEGMENTS 256
#define SEGS_PER_INDIRECT_FRAME \
- (PAGE_SIZE/sizeof(struct blkif_request_segment_aligned))
+ (PAGE_SIZE/sizeof(struct blkif_request_segment))
#define MAX_INDIRECT_PAGES \
((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
#define INDIRECT_PAGES(_segs) \
@@ -278,6 +278,7 @@ struct xen_blkif {
/* for barrier (drain) requests */
struct completion drain_complete;
atomic_t drain;
+ atomic_t inflight;
/* One thread per one blkif. */
struct task_struct *xenblkd;
unsigned int waiting_reqs;
@@ -376,6 +377,7 @@ int xen_blkif_xenbus_init(void);
irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
int xen_blkif_schedule(void *arg);
int xen_blkif_purge_persistent(void *arg);
+void xen_blkbk_free_caches(struct xen_blkif *blkif);
int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
struct backend_info *be, int state);
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index c2014a0aa206..84973c6a856a 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -125,8 +125,10 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
blkif->persistent_gnts.rb_node = NULL;
spin_lock_init(&blkif->free_pages_lock);
INIT_LIST_HEAD(&blkif->free_pages);
+ INIT_LIST_HEAD(&blkif->persistent_purge_list);
blkif->free_pages_num = 0;
atomic_set(&blkif->persistent_gnt_in_use, 0);
+ atomic_set(&blkif->inflight, 0);
INIT_LIST_HEAD(&blkif->pending_free);
@@ -259,6 +261,17 @@ static void xen_blkif_free(struct xen_blkif *blkif)
if (!atomic_dec_and_test(&blkif->refcnt))
BUG();
+ /* Remove all persistent grants and the cache of ballooned pages. */
+ xen_blkbk_free_caches(blkif);
+
+ /* Make sure everything is drained before shutting down */
+ BUG_ON(blkif->persistent_gnt_c != 0);
+ BUG_ON(atomic_read(&blkif->persistent_gnt_in_use) != 0);
+ BUG_ON(blkif->free_pages_num != 0);
+ BUG_ON(!list_empty(&blkif->persistent_purge_list));
+ BUG_ON(!list_empty(&blkif->free_pages));
+ BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
+
/* Check that there is no request in use */
list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
list_del(&req->free_list);