SCSI: fix race in device_create

There is a race from when a device is created with device_create() and
then the drvdata is set with a call to dev_set_drvdata() in which a
sysfs file could be open, yet the drvdata will be NULL, causing all
sorts of bad things to happen.

This patch fixes the problem by using the new function,
device_create_drvdata().  It fixes the problem in all of the scsi
drivers that need it.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4 files changed, 17 insertions, 16 deletions

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index 75c84d7b9ce8..c4b938bc30d3 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -910,9 +910,9 @@ static int ch_probe(struct device *dev)
         ch->minor = minor;
         sprintf(ch->name,"ch%d",ch->minor);
 
-        class_dev = device_create(ch_sysfs_class, dev,
-                                  MKDEV(SCSI_CHANGER_MAJOR,ch->minor),
-                                  "s%s", ch->name);
+        class_dev = device_create_drvdata(ch_sysfs_class, dev,
+                                          MKDEV(SCSI_CHANGER_MAJOR, ch->minor),
+                                          ch, "s%s", ch->name);
         if (IS_ERR(class_dev)) {
                 printk(KERN_WARNING "ch%d: device_create failed\n",
                        ch->minor);
@@ -926,7 +926,6 @@ static int ch_probe(struct device *dev)
         if (init)
                 ch_init_elem(ch);
 
-        dev_set_drvdata(dev, ch);
         sdev_printk(KERN_INFO, sd, "Attached scsi changer %s\n", ch->name);
 
         return 0;
diff --git a/drivers/scsi/osst.c b/drivers/scsi/osst.c
index 31f7aec44d90..243d8becd30f 100644
--- a/drivers/scsi/osst.c
+++ b/drivers/scsi/osst.c
@@ -5695,13 +5695,12 @@ static int osst_sysfs_add(dev_t dev, struct device *device, struct osst_tape * S
         struct device *osst_member;
         int err;
 
-        osst_member = device_create(osst_sysfs_class, device, dev, "%s", name);
+        osst_member = device_create_drvdata(osst_sysfs_class, device, dev, STp, "%s", name);
         if (IS_ERR(osst_member)) {
                 printk(KERN_WARNING "osst :W: Unable to add sysfs class member %s\n", name);
                 return PTR_ERR(osst_member);
         }
 
-        dev_set_drvdata(osst_member, STp);
         err = device_create_file(osst_member, &dev_attr_ADR_rev);
         if (err)
                 goto err_out;
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index c9d7f721b9e2..ea0edd1b2e76 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1441,17 +1441,18 @@ sg_add(struct device *cl_dev, struct class_interface *cl_intf)
         if (sg_sysfs_valid) {
                 struct device *sg_class_member;
 
-                sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
-                                                MKDEV(SCSI_GENERIC_MAJOR,
-                                                      sdp->index),
-                                                "%s", disk->disk_name);
+                sg_class_member = device_create_drvdata(sg_sysfs_class,
+                                                        cl_dev->parent,
+                                                        MKDEV(SCSI_GENERIC_MAJOR,
+                                                              sdp->index),
+                                                        sdp,
+                                                        "%s", disk->disk_name);
                 if (IS_ERR(sg_class_member)) {
                         printk(KERN_ERR "sg_add: "
                                "device_create failed\n");
                         error = PTR_ERR(sg_class_member);
                         goto cdev_add_err;
                 }
-                dev_set_drvdata(sg_class_member, sdp);
                 error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
                                           &sg_class_member->kobj, "generic");
                 if (error)
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index e8db66ad0bde..6e5a5bb31311 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4424,17 +4424,19 @@ static int do_create_class_files(struct scsi_tape *STp, int dev_num, int mode)
                 snprintf(name, 10, "%s%s%s", rew ? "n" : "",
                          STp->disk->disk_name, st_formats[i]);
                 st_class_member =
-                        device_create(st_sysfs_class, &STp->device->sdev_gendev,
-                                      MKDEV(SCSI_TAPE_MAJOR,
-                                                TAPE_MINOR(dev_num, mode, rew)),
-                                      "%s", name);
+                        device_create_drvdata(st_sysfs_class,
+                                              &STp->device->sdev_gendev,
+                                              MKDEV(SCSI_TAPE_MAJOR,
+                                                    TAPE_MINOR(dev_num,
+                                                              mode, rew)),
+                                              &STp->modes[mode],
+                                              "%s", name);
                 if (IS_ERR(st_class_member)) {
                         printk(KERN_WARNING "st%d: device_create failed\n",
                                dev_num);
                         error = PTR_ERR(st_class_member);
                         goto out;
                 }
-                dev_set_drvdata(st_class_member, &STp->modes[mode]);
 
                 error = device_create_file(st_class_member,
                                            &dev_attr_defined);