Commit 90fa1527 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon

dm snapshot: change yield to msleep

Change yield() to msleep(1). If the thread had realtime priority,
yield() doesn't really yield, so the yielding process would loop
indefinitely and cause machine lockup.
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent a1b51e98
...@@ -9,6 +9,7 @@ ...@@ -9,6 +9,7 @@
#include <linux/blkdev.h> #include <linux/blkdev.h>
#include <linux/ctype.h> #include <linux/ctype.h>
#include <linux/device-mapper.h> #include <linux/device-mapper.h>
#include <linux/delay.h>
#include <linux/fs.h> #include <linux/fs.h>
#include <linux/init.h> #include <linux/init.h>
#include <linux/kdev_t.h> #include <linux/kdev_t.h>
...@@ -735,7 +736,7 @@ static void snapshot_dtr(struct dm_target *ti) ...@@ -735,7 +736,7 @@ static void snapshot_dtr(struct dm_target *ti)
unregister_snapshot(s); unregister_snapshot(s);
while (atomic_read(&s->pending_exceptions_count)) while (atomic_read(&s->pending_exceptions_count))
yield(); msleep(1);
/* /*
* Ensure instructions in mempool_destroy aren't reordered * Ensure instructions in mempool_destroy aren't reordered
* before atomic_read. * before atomic_read.
...@@ -888,10 +889,10 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success) ...@@ -888,10 +889,10 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success)
/* /*
* Check for conflicting reads. This is extremely improbable, * Check for conflicting reads. This is extremely improbable,
* so yield() is sufficient and there is no need for a wait queue. * so msleep(1) is sufficient and there is no need for a wait queue.
*/ */
while (__chunk_is_tracked(s, pe->e.old_chunk)) while (__chunk_is_tracked(s, pe->e.old_chunk))
yield(); msleep(1);
/* /*
* Add a proper exception, and remove the * Add a proper exception, and remove the
......
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