Fix bug 7994 sleeping function called from invalid context

  - addresses the reported bug (with GFP_KERNEL -> GFP_ATOMIC)
  - improves error checking, and
  - is a subset of the changes to scsi_debug in lk 2.6.21-rc*

Compiled and lightly tested (in lk 2.6.21-rc2 environment).
Signed-off-by: Douglas Gilbert <dougg@torque.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/scsi/scsi_debug.c

@@ -954,7 +954,9 @@ static int resp_inquiry(struct scsi_cmnd * scp, int target,
 	int alloc_len, n, ret;
 
 	alloc_len = (cmd[3] << 8) + cmd[4];
-	arr = kzalloc(SDEBUG_MAX_INQ_ARR_SZ, GFP_KERNEL);
+	arr = kzalloc(SDEBUG_MAX_INQ_ARR_SZ, GFP_ATOMIC);
+	if (! arr)
+		return DID_REQUEUE << 16;
 	if (devip->wlun)
 		pq_pdt = 0x1e;	/* present, wlun */
 	else if (scsi_debug_no_lun_0 && (0 == devip->lun))
@@ -1217,7 +1219,9 @@ static int resp_report_tgtpgs(struct scsi_cmnd * scp,
 	alen = ((cmd[6] << 24) + (cmd[7] << 16) + (cmd[8] << 8)
 		+ cmd[9]);
 
-	arr = kzalloc(SDEBUG_MAX_TGTPGS_ARR_SZ, GFP_KERNEL);
+	arr = kzalloc(SDEBUG_MAX_TGTPGS_ARR_SZ, GFP_ATOMIC);
+	if (! arr)
+		return DID_REQUEUE << 16;
 	/*
 	 * EVPD page 0x88 states we have two ports, one
 	 * real and a fake port with no device connected.
@@ -1996,6 +2000,8 @@ static int scsi_debug_slave_configure(struct scsi_device * sdp)
 	if (sdp->host->max_cmd_len != SCSI_DEBUG_MAX_CMD_LEN)
 		sdp->host->max_cmd_len = SCSI_DEBUG_MAX_CMD_LEN;
 	devip = devInfoReg(sdp);
+	if (NULL == devip)
+		return 1;       /* no resources, will be marked offline */
 	sdp->hostdata = devip;
 	if (sdp->host->cmd_per_lun)
 		scsi_adjust_queue_depth(sdp, SDEBUG_TAGGED_QUEUING,
@@ -2044,7 +2050,7 @@ static struct sdebug_dev_info * devInfoReg(struct scsi_device * sdev)
 		}
 	}
 	if (NULL == open_devip) { /* try and make a new one */
-		open_devip = kzalloc(sizeof(*open_devip),GFP_KERNEL);
+		open_devip = kzalloc(sizeof(*open_devip),GFP_ATOMIC);
 		if (NULL == open_devip) {
 			printk(KERN_ERR "%s: out of memory at line %d\n",
 				__FUNCTION__, __LINE__);