diff mbox

[04/17] Update the ch driver to use idr helper functions.

Message ID 1a6d624b850fa7543c9c1fcca647ddb654954296.1442263513.git.lduncan@suse.com (mailing list archive)
State New, archived
Headers show

Commit Message

Lee Duncan Sept. 16, 2015, 5:50 p.m. UTC
Note: when allocating an index, in the error case,
where the just-allocated index has to be released,
the required locking around the index removal was
not present, so this conversion has the side effect
of adding locking for that error condition. This
should close a possible race condition that could
have resulted in duplicate index allocation.

Signed-off-by: Lee Duncan <lduncan@suse.com>
---
 drivers/scsi/ch.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)
diff mbox

Patch

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index dad959fcf6d8..2edf1f8883f9 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -909,12 +909,8 @@  static int ch_probe(struct device *dev)
 	if (NULL == ch)
 		return -ENOMEM;
 
-	idr_preload(GFP_KERNEL);
-	spin_lock(&ch_index_lock);
-	ret = idr_alloc(&ch_index_idr, ch, 0, CH_MAX_DEVS + 1, GFP_NOWAIT);
-	spin_unlock(&ch_index_lock);
-	idr_preload_end();
-
+	ret = idr_get_index_in_range(&ch_index_idr, &ch_index_lock, ch,
+				     0, CH_MAX_DEVS + 1);
 	if (ret < 0) {
 		if (ret == -ENOSPC)
 			ret = -ENODEV;
@@ -945,7 +941,7 @@  static int ch_probe(struct device *dev)
 
 	return 0;
 remove_idr:
-	idr_remove(&ch_index_idr, ch->minor);
+	idr_put_index(&ch_index_idr, &ch_index_lock, ch->minor);
 free_ch:
 	kfree(ch);
 	return ret;
@@ -955,9 +951,7 @@  static int ch_remove(struct device *dev)
 {
 	scsi_changer *ch = dev_get_drvdata(dev);
 
-	spin_lock(&ch_index_lock);
-	idr_remove(&ch_index_idr, ch->minor);
-	spin_unlock(&ch_index_lock);
+	idr_put_index(&ch_index_idr, &ch_index_lock, ch->minor);
 
 	device_destroy(ch_sysfs_class, MKDEV(SCSI_CHANGER_MAJOR,ch->minor));
 	kfree(ch->dt);