libata: Fixup n_elem initialization

Fixup the inialization of qc->n_elem. It currently gets
initialized to 1 for commands that do not transfer any data.
Fix this by initializing n_elem to 0 and only setting to 1
in ata_scsi_qc_new when there is data to transfer. This fixes
some problems seen with SATA devices attached to ipr adapters.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 836947da5b14..7cc5a4a910a4 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -372,7 +372,7 @@ struct ata_queued_cmd *ata_scsi_qc_new(struct ata_device *dev,
                 if (cmd->use_sg) {
                         qc->__sg = (struct scatterlist *) cmd->request_buffer;
                         qc->n_elem = cmd->use_sg;
-                } else {
+                } else if (cmd->request_bufflen) {
                         qc->__sg = &qc->sgent;
                         qc->n_elem = 1;
                 }