[34-longterm 161/196] mpt2sas: fix the incorrect scsi_dma_map error checking

[Paul Gortmaker]

From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit bb789d01620e5d36081b22edb6fb71cf55ff043c upstream.

scsi_dma_map() returns -1 if an error occurred (zero means that the
command has no data). So the following current code can't catch an
error:

sges_left = scsi_dma_map(scmd);
if (!sges_left) {
	sdev_printk(KERN_ERR, scmd->device, "pci_map_sg"
	" failed: request for %d bytes!\n", scsi_bufflen(scmd));
	return -ENOMEM;
}

Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Acked-by: "Desai, Kashyap" <Kashyap.Desai@xxxxxxx>
Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 drivers/scsi/mpt2sas/mpt2sas_scsih.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index 87cf0d2..8d98f09 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -988,7 +988,7 @@ _scsih_build_scatter_gather(struct MPT2SAS_ADAPTER *ioc,
 	u32 chain_offset;
 	u32 chain_length;
 	u32 chain_flags;
-	u32 sges_left;
+	int sges_left;
 	u32 sges_in_segment;
 	u32 sgl_flags;
 	u32 sgl_flags_last_element;
@@ -1009,7 +1009,7 @@ _scsih_build_scatter_gather(struct MPT2SAS_ADAPTER *ioc,
 
 	sg_scmd = scsi_sglist(scmd);
 	sges_left = scsi_dma_map(scmd);
-	if (!sges_left) {
+	if (sges_left < 0) {
 		sdev_printk(KERN_ERR, scmd->device, "pci_map_sg"
 		" failed: request for %d bytes!\n", scsi_bufflen(scmd));
 		return -ENOMEM;
-- 
1.7.9.3

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