@detached is set under the protection of sg_index_lock. Without getting the
lock, new sfp will be added during sg removal and there is no chance for it
to be picked out. So check with sg_index_lock held in sg_add_sfp().
Changes from v4:
* use ERR_PTR series instead of adding another parameter in sg_add_sfp
Signed-off-by: Vaughan Cao <vaughan.cao@xxxxxxxxxx>
---
drivers/scsi/sg.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 671b760..f0e4785 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -295,21 +295,17 @@ sg_open(struct inode *inode, struct file *filp)
if (flags & O_EXCL)
sdp->exclude = 1; /* used by release lock */
- if (sdp->detached) {
- retval = -ENODEV;
- goto sem_out;
- }
if (sfds_list_empty(sdp)) { /* no existing opens on this device */
sdp->sgdebug = 0;
q = sdp->device->request_queue;
sdp->sg_tablesize = queue_max_segments(q);
}
- if ((sfp = sg_add_sfp(sdp, dev)))
- filp->private_data = sfp;
- else {
- retval = -ENOMEM;
+ sfp = sg_add_sfp(sdp, dev);
+ if (IS_ERR(sfp)) {
+ retval = PTR_ERR(sfp);
goto sem_out;
}
+ filp->private_data = sfp;
retval = 0;
if (retval) {
@@ -2055,7 +2051,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
if (!sfp)
- return NULL;
+ return ERR_PTR(-ENOMEM);
init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);
@@ -2070,6 +2066,10 @@ sg_add_sfp(Sg_device * sdp, int dev)
sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
sfp->parentdp = sdp;
write_lock_irqsave(&sg_index_lock, iflags);
+ if (sdp->detached) {
+ write_unlock_irqrestore(&sg_index_lock, iflags);
+ return ERR_PTR(-ENODEV);
+ }
list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
write_unlock_irqrestore(&sg_index_lock, iflags);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
--
1.7.11.7
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