Patch "dasd: refactor dasd_ioctl_information" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    dasd: refactor dasd_ioctl_information

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     dasd-refactor-dasd_ioctl_information.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ed0740831c07938ebf16f5cdc1ee1ae960c6bc71
Author: Christoph Hellwig <hch@xxxxxx>
Date:   Tue May 19 16:22:58 2020 +0200

    dasd: refactor dasd_ioctl_information
    
    [ Upstream commit 9353848c6589ffe6373d03f3a58feaeda1009641 ]
    
    Prepare for in-kernel callers of this functionality.
    
    Signed-off-by: Christoph Hellwig <hch@xxxxxx>
    [sth@xxxxxxxxxx: remove leftover kfree]
    Signed-off-by: Stefan Haberland <sth@xxxxxxxxxxxxx>
    Reviewed-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxx>
    Reviewed-by: Jan Hoeppner <hoeppner@xxxxxxxxxxxxx>
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Stable-dep-of: ccc45cb4e727 ("s390/dasd: Use correct lock while counting channel queue length")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index 9a5f3add325fc..9b7782395c379 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -457,10 +457,9 @@ static int dasd_ioctl_read_profile(struct dasd_block *block, void __user *argp)
 /*
  * Return dasd information. Used for BIODASDINFO and BIODASDINFO2.
  */
-static int dasd_ioctl_information(struct dasd_block *block,
-				  unsigned int cmd, void __user *argp)
+static int __dasd_ioctl_information(struct dasd_block *block,
+		struct dasd_information2_t *dasd_info)
 {
-	struct dasd_information2_t *dasd_info;
 	struct subchannel_id sch_id;
 	struct ccw_dev_id dev_id;
 	struct dasd_device *base;
@@ -473,15 +472,9 @@ static int dasd_ioctl_information(struct dasd_block *block,
 	if (!base->discipline || !base->discipline->fill_info)
 		return -EINVAL;
 
-	dasd_info = kzalloc(sizeof(struct dasd_information2_t), GFP_KERNEL);
-	if (dasd_info == NULL)
-		return -ENOMEM;
-
 	rc = base->discipline->fill_info(base, dasd_info);
-	if (rc) {
-		kfree(dasd_info);
+	if (rc)
 		return rc;
-	}
 
 	cdev = base->cdev;
 	ccw_device_get_id(cdev, &dev_id);
@@ -520,15 +513,24 @@ static int dasd_ioctl_information(struct dasd_block *block,
 	list_for_each(l, &base->ccw_queue)
 		dasd_info->chanq_len++;
 	spin_unlock_irqrestore(&block->queue_lock, flags);
+	return 0;
+}
 
-	rc = 0;
-	if (copy_to_user(argp, dasd_info,
-			 ((cmd == (unsigned int) BIODASDINFO2) ?
-			  sizeof(struct dasd_information2_t) :
-			  sizeof(struct dasd_information_t))))
-		rc = -EFAULT;
+static int dasd_ioctl_information(struct dasd_block *block, void __user *argp,
+		size_t copy_size)
+{
+	struct dasd_information2_t *dasd_info;
+	int error;
+
+	dasd_info = kzalloc(sizeof(*dasd_info), GFP_KERNEL);
+	if (!dasd_info)
+		return -ENOMEM;
+
+	error = __dasd_ioctl_information(block, dasd_info);
+	if (!error && copy_to_user(argp, dasd_info, copy_size))
+		error = -EFAULT;
 	kfree(dasd_info);
-	return rc;
+	return error;
 }
 
 /*
@@ -622,10 +624,12 @@ int dasd_ioctl(struct block_device *bdev, fmode_t mode,
 		rc = dasd_ioctl_check_format(bdev, argp);
 		break;
 	case BIODASDINFO:
-		rc = dasd_ioctl_information(block, cmd, argp);
+		rc = dasd_ioctl_information(block, argp,
+				sizeof(struct dasd_information_t));
 		break;
 	case BIODASDINFO2:
-		rc = dasd_ioctl_information(block, cmd, argp);
+		rc = dasd_ioctl_information(block, argp,
+				sizeof(struct dasd_information2_t));
 		break;
 	case BIODASDPRRD:
 		rc = dasd_ioctl_read_profile(block, argp);