[Devel] [PATCH RHEL7 COMMIT] ploop: kthread_create() errors processing

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-862.11.6.vz7.71.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-862.11.6.vz7.71.14
------>
commit d699ffb298410ffcc2f1c7fd0239da22a888cb27
Author: Vasily Averin <vvs at virtuozzo.com>
Date:   Wed Sep 26 17:43:48 2018 +0300

    ploop: kthread_create() errors processing
    
    kthread_create() returns not NULL but ERR_PTR in case of internal failures.
    
    https://jira.sw.ru/browse/PSBM-88561
    
    Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
    Reviewed-by: Evgenii Shatokhin <eshatokhin at virtuozzo.com>
    
    v2: extra netfilter hunks was removed.
---
 drivers/block/ploop/io_direct.c | 10 +++++++---
 drivers/block/ploop/io_kaio.c   | 11 +++++++----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/block/ploop/io_direct.c b/drivers/block/ploop/io_direct.c
index 6ea98901b7d4..56c3559b179e 100644
--- a/drivers/block/ploop/io_direct.c
+++ b/drivers/block/ploop/io_direct.c
@@ -1004,7 +1004,9 @@ static int dio_open(struct ploop_io * io)
 		io->fsync_thread = kthread_create(dio_fsync_thread,
 						  io, "ploop_fsync%d",
 						  delta->plo->index);
-		if (io->fsync_thread == NULL) {
+		if (IS_ERR(io->fsync_thread)) {
+			err = PTR_ERR(io->fsync_thread);
+			io->fsync_thread = NULL;
 			io->files.em_tree = NULL;
 			ploop_dio_close(io, 0);
 			goto out;
@@ -1731,9 +1733,11 @@ static int dio_prepare_merge(struct ploop_io * io, struct ploop_snapdata *sd)
 		io->fsync_thread = kthread_create(dio_fsync_thread,
 						  io, "ploop_fsync%d",
 						  io->plo->index);
-		if (io->fsync_thread == NULL) {
+		if (IS_ERR(io->fsync_thread)) {
+			err = PTR_ERR(io->fsync_thread);
+			io->fsync_thread = NULL;
 			fput(file);
-			return -ENOMEM;
+			return err;
 		}
 		wake_up_process(io->fsync_thread);
 	}
diff --git a/drivers/block/ploop/io_kaio.c b/drivers/block/ploop/io_kaio.c
index 48baa447ef91..1ea63de3030b 100644
--- a/drivers/block/ploop/io_kaio.c
+++ b/drivers/block/ploop/io_kaio.c
@@ -887,9 +887,11 @@ static int kaio_open(struct ploop_io * io)
 		io->fsync_thread = kthread_create(kaio_fsync_thread,
 						  io, "ploop_fsync%d",
 						  delta->plo->index);
-		if (io->fsync_thread == NULL) {
+		if (IS_ERR(io->fsync_thread)) {
+			err = PTR_ERR(io->fsync_thread);
+			io->fsync_thread = NULL;
 			ploop_kaio_close(io->files.mapping, 0);
-			return -ENOMEM;
+			return err;
 		}
 
 		wake_up_process(io->fsync_thread);
@@ -985,8 +987,9 @@ static int kaio_prepare_merge(struct ploop_io * io, struct ploop_snapdata *sd)
 	io->fsync_thread = kthread_create(kaio_fsync_thread,
 					  io, "ploop_fsync%d",
 					  io->plo->index);
-	if (io->fsync_thread == NULL) {
-		err = -ENOMEM;
+	if (IS_ERR(io->fsync_thread)) {
+		err = PTR_ERR(io->fsync_thread);
+		io->fsync_thread = NULL;
 		goto prep_merge_done;
 	}