[PATCH 4.14 02/36] blkdev_report_zones_ioctl(): Use vmalloc() to allocate large buffers

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bart Van Assche <bart.vanassche@xxxxxxx>

commit 327ea4adcfa37194739f1ec7c70568944d292281 upstream.

Avoid that complaints similar to the following appear in the kernel log
if the number of zones is sufficiently large:

  fio: page allocation failure: order:9, mode:0x140c0c0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null)
  Call Trace:
  dump_stack+0x63/0x88
  warn_alloc+0xf5/0x190
  __alloc_pages_slowpath+0x8f0/0xb0d
  __alloc_pages_nodemask+0x242/0x260
  alloc_pages_current+0x6a/0xb0
  kmalloc_order+0x18/0x50
  kmalloc_order_trace+0x26/0xb0
  __kmalloc+0x20e/0x220
  blkdev_report_zones_ioctl+0xa5/0x1a0
  blkdev_ioctl+0x1ba/0x930
  block_ioctl+0x41/0x50
  do_vfs_ioctl+0xaa/0x610
  SyS_ioctl+0x79/0x90
  do_syscall_64+0x79/0x1b0
  entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls")
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Shaun Tancheff <shaun.tancheff@xxxxxxxxxxx>
Cc: Damien Le Moal <damien.lemoal@xxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 block/blk-zoned.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -286,7 +286,11 @@ int blkdev_report_zones_ioctl(struct blo
 	if (!rep.nr_zones)
 		return -EINVAL;
 
-	zones = kcalloc(rep.nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
+	if (rep.nr_zones > INT_MAX / sizeof(struct blk_zone))
+		return -ERANGE;
+
+	zones = kvmalloc(rep.nr_zones * sizeof(struct blk_zone),
+			GFP_KERNEL | __GFP_ZERO);
 	if (!zones)
 		return -ENOMEM;
 
@@ -308,7 +312,7 @@ int blkdev_report_zones_ioctl(struct blo
 	}
 
  out:
-	kfree(zones);
+	kvfree(zones);
 
 	return ret;
 }