Re: [PATCH v2] scsi: libsas: fix length error in sas_smp_handler()

[John Garry]

On 07/12/2017 10:57, Jason Yan wrote:
The bsg_job_done() requires the length of payload received, but we give
it the untransferred residual.

As I understand, this patches fixes (SES) enclosure management for 
libsas, so it's quite an important patch.

Thanks,
John

Fixes: 651a01364994 ("scsi: scsi_transport_sas: switch to bsg-lib for SMP 
passthrough")
Reported-and-tested-by: chenqilin <chenqil...@huawei.com>
Signed-off-by: Jason Yan <yanai...@huawei.com>
CC: Christoph Hellwig <h...@lst.de>
---
 drivers/scsi/libsas/sas_expander.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/libsas/sas_expander.c 
b/drivers/scsi/libsas/sas_expander.c
index 50cb0f3..6c40ecc 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -2143,7 +2143,7 @@ void sas_smp_handler(struct bsg_job *job, struct 
Scsi_Host *shost,
                struct sas_rphy *rphy)
 {
        struct domain_device *dev;
-       unsigned int reslen = 0;
+       unsigned int rcvlen = 0;
        int ret = -EINVAL;

        /* no rphy means no smp target support (ie aic94xx host) */
@@ -2177,12 +2177,12 @@ void sas_smp_handler(struct bsg_job *job, struct 
Scsi_Host *shost,

        ret = smp_execute_task_sg(dev, job->request_payload.sg_list,
                        job->reply_payload.sg_list);
-       if (ret > 0) {
-               /* positive number is the untransferred residual */
-               reslen = ret;
+       if (ret >= 0) {
+               /* bsg_job_done() requires the length received  */
+               rcvlen = job->reply_payload.payload_len - ret;
                ret = 0;
        }

 out:
-       bsg_job_done(job, ret, reslen);
+       bsg_job_done(job, ret, rcvlen);
 }