Commit 621f6401 authored Dec 11, 2017 by Jason Yan Committed by Martin K. Petersen Dec 11, 2017

scsi: libsas: fix length error in sas_smp_handler()



The return value of smp_execute_task_sg() is the untransferred residual,
but bsg_job_done() requires the length of payload received. This makes
SMP passthrough commands from userland by sg ioctl to libsas get a wrong
response. The userland tools such as smp_utils failed because of these
wrong responses:

~#smp_discover /dev/bsg/expander-2\:13
response too short, len=0
~#smp_discover /dev/bsg/expander-2\:134
response too short, len=0

Fix this by passing the actual received length to bsg_job_done(). And if
smp_execute_task_sg() returns 0, this means received length is exactly
the buffer length.

[mkp: typo]

Fixes: 651a0136 ("scsi: scsi_transport_sas: switch to bsg-lib for SMP passthrough")
Cc: <stable@vger.kernel.org> # v4.14+
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reported-by: chenqilin <chenqilin2@huawei.com>
Tested-by: chenqilin <chenqilin2@huawei.com>
CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent 48d83282

drivers/scsi/libsas/sas_expander.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -2145,7 +2145,7 @@ 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) */
		@@ -2179,12 +2179,12 @@ 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);
		}