[PATCH] ibmvscsi: use GFP_ATOMIC with dma_alloc_coherent in map_sg_data

[Tyrel Datwyler]

While mapping DMA for scatter list when a scsi command is queued the
existing call to dma_alloc_coherent() in our map_sg_data() function
passes zero for the gfp_flags parameter. We are most definitly in atomic
context at this point as queue_command() is called in softirq context
and further we have a spinlock holding the scsi host lock.

Fix this by passing GFP_ATOMIC to dma_alloc_coherent() to prevent any
sort of sleeping in atomic context deadlock.

Fixes: 4dddbc26c389 ("[SCSI] ibmvscsi: handle large scatter/gather lists")
Cc: stable at vger.kernel.org
Signed-off-by: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 1135e74..cb8535e 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -731,7 +731,7 @@ static int map_sg_data(struct scsi_cmnd *cmd,
 		evt_struct->ext_list = (struct srp_direct_buf *)
 			dma_alloc_coherent(dev,
 					   SG_ALL * sizeof(struct srp_direct_buf),
-					   &evt_struct->ext_list_token, 0);
+					   &evt_struct->ext_list_token, GFP_ATOMIC);
 		if (!evt_struct->ext_list) {
 			if (!firmware_has_feature(FW_FEATURE_CMO))
 				sdev_printk(KERN_ERR, cmd->device,
-- 
1.8.3.1