This is a update to a previous patch that fixed some sg might sleep
errors.
This patch corrects a problem in sg.c where a lock is held during calls to
vmalloc and calls for device model registration.
Note:
Douglas Gilbert is the maintainer of this driver.
[email protected]
http://www.torque.net/sg/
During Douglas Gilbert's time-off he connects when he can so it
maybe a bit until he can address this.
In the interim this patch should fix the problem, and
still provide for safe additions.
The full patch is available at:
http://www-124.ibm.com/storageio/patches/2.5/sg
-andmike
--
Michael Anderson
[email protected]
sg.c | 83 +++++++++++++++++++++++++++++++++++++++++--------------------------
1 files changed, 52 insertions(+), 31 deletions(-)
-----
diff -Nru a/drivers/scsi/sg.c b/drivers/scsi/sg.c
--- a/drivers/scsi/sg.c Fri Oct 4 11:53:21 2002
+++ b/drivers/scsi/sg.c Fri Oct 4 11:53:21 2002
@@ -1354,32 +1354,42 @@
{
static int sg_registered = 0;
unsigned long iflags;
+ int tmp_dev_max;
+ Sg_device **tmp_da;
if ((sg_template.dev_noticed == 0) || sg_dev_arr)
return 0;
+ SCSI_LOG_TIMEOUT(3, printk("sg_init\n"));
+
+ write_lock_irqsave(&sg_dev_arr_lock, iflags);
+ tmp_dev_max = sg_template.dev_noticed + SG_DEV_ARR_LUMP;
+ write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
+
+ tmp_da = (Sg_device **)vmalloc(
+ tmp_dev_max * sizeof(Sg_device *));
+ if (NULL == tmp_da) {
+ printk(KERN_ERR "sg_init: no space for sg_dev_arr\n");
+ return 1;
+ }
write_lock_irqsave(&sg_dev_arr_lock, iflags);
+
if (!sg_registered) {
if (register_chrdev(SCSI_GENERIC_MAJOR, "sg", &sg_fops)) {
printk(KERN_ERR
"Unable to get major %d for generic SCSI device\n",
SCSI_GENERIC_MAJOR);
write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
+ vfree((char *) tmp_da);
return 1;
}
sg_registered++;
}
- SCSI_LOG_TIMEOUT(3, printk("sg_init\n"));
- sg_template.dev_max = sg_template.dev_noticed + SG_DEV_ARR_LUMP;
- sg_dev_arr = (Sg_device **)vmalloc(
- sg_template.dev_max * sizeof(Sg_device *));
- if (NULL == sg_dev_arr) {
- printk(KERN_ERR "sg_init: no space for sg_dev_arr\n");
- write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
- return 1;
- }
- memset(sg_dev_arr, 0, sg_template.dev_max * sizeof (Sg_device *));
+ memset(tmp_da, 0, tmp_dev_max * sizeof (Sg_device *));
+ sg_template.dev_max = tmp_dev_max;
+ sg_dev_arr = tmp_da;
+
write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
#ifdef CONFIG_PROC_FS
sg_proc_init();
@@ -1430,7 +1440,7 @@
static int
sg_attach(Scsi_Device * scsidp)
{
- Sg_device *sdp;
+ Sg_device *sdp = NULL;
unsigned long iflags;
int k;
@@ -1439,15 +1449,16 @@
Sg_device **tmp_da;
int tmp_dev_max = sg_template.nr_dev + SG_DEV_ARR_LUMP;
+ write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
tmp_da = (Sg_device **)vmalloc(
tmp_dev_max * sizeof(Sg_device *));
if (NULL == tmp_da) {
scsidp->attached--;
- write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
printk(KERN_ERR
"sg_attach: device array cannot be resized\n");
return 1;
}
+ write_lock_irqsave(&sg_dev_arr_lock, iflags);
memset(tmp_da, 0, tmp_dev_max * sizeof (Sg_device *));
memcpy(tmp_da, sg_dev_arr,
sg_template.dev_max * sizeof (Sg_device *));
@@ -1456,6 +1467,7 @@
sg_template.dev_max = tmp_dev_max;
}
+find_empty_slot:
for (k = 0; k < sg_template.dev_max; k++)
if (!sg_dev_arr[k])
break;
@@ -1467,11 +1479,19 @@
" type=%d, minor number exceed %d\n",
scsidp->host->host_no, scsidp->channel, scsidp->id,
scsidp->lun, scsidp->type, SG_MAX_DEVS_MASK);
+ if (NULL != sdp)
+ vfree((char *) sdp);
return 1;
}
- if (k < sg_template.dev_max)
- sdp = (Sg_device *)vmalloc(sizeof(Sg_device));
- else
+ if (k < sg_template.dev_max) {
+ if (NULL == sdp) {
+ write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
+ sdp = (Sg_device *)vmalloc(sizeof(Sg_device));
+ write_lock_irqsave(&sg_dev_arr_lock, iflags);
+ if (!sg_dev_arr[k])
+ goto find_empty_slot;
+ }
+ } else
sdp = NULL;
if (NULL == sdp) {
scsidp->attached--;
@@ -1498,17 +1518,18 @@
scsidp->sdev_driverfs_dev.name);
sdp->sg_driverfs_dev.parent = &scsidp->sdev_driverfs_dev;
sdp->sg_driverfs_dev.bus = &scsi_driverfs_bus_type;
+
+ sg_template.nr_dev++;
+ sg_dev_arr[k] = sdp;
+ write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
+
device_register(&sdp->sg_driverfs_dev);
device_create_file(&sdp->sg_driverfs_dev, &dev_attr_type);
device_create_file(&sdp->sg_driverfs_dev, &dev_attr_kdev);
-
sdp->de = devfs_register(scsidp->de, "generic", DEVFS_FL_DEFAULT,
SCSI_GENERIC_MAJOR, k,
S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP,
&sg_fops, sdp);
- sg_template.nr_dev++;
- sg_dev_arr[k] = sdp;
- write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
switch (scsidp->type) {
case TYPE_DISK:
case TYPE_MOD:
@@ -1529,7 +1550,7 @@
static void
sg_detach(Scsi_Device * scsidp)
{
- Sg_device *sdp;
+ Sg_device *sdp = NULL;
unsigned long iflags;
Sg_fd *sfp;
Sg_fd *tsfp;
@@ -1571,22 +1592,11 @@
}
}
SCSI_LOG_TIMEOUT(3, printk("sg_detach: dev=%d, dirty\n", k));
- devfs_unregister(sdp->de);
- device_remove_file(&sdp->sg_driverfs_dev,
- &dev_attr_type);
- device_remove_file(&sdp->sg_driverfs_dev,
- &dev_attr_kdev);
- put_device(&sdp->sg_driverfs_dev);
- sdp->de = NULL;
if (NULL == sdp->headfp) {
- vfree((char *) sdp);
sg_dev_arr[k] = NULL;
}
} else { /* nothing active, simple case */
SCSI_LOG_TIMEOUT(3, printk("sg_detach: dev=%d\n", k));
- devfs_unregister(sdp->de);
- put_device(&sdp->sg_driverfs_dev);
- vfree((char *) sdp);
sg_dev_arr[k] = NULL;
}
scsidp->attached--;
@@ -1595,6 +1605,17 @@
break;
}
write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
+
+ if (sdp) {
+ devfs_unregister(sdp->de);
+ sdp->de = NULL;
+ device_remove_file(&sdp->sg_driverfs_dev, &dev_attr_type);
+ device_remove_file(&sdp->sg_driverfs_dev, &dev_attr_kdev);
+ put_device(&sdp->sg_driverfs_dev);
+ if (NULL == sdp->headfp)
+ vfree((char *) sdp);
+ }
+
if (delay)
scsi_sleep(2); /* dirty detach so delay device destruction */
}