scsi: bsg: Move bsg_scsi_ops to drivers/scsi/

Move the SCSI-specific bsg code in the SCSI midlayer instead of in the
common bsg code.  This just keeps the common bsg code block/ and also
allows building it as a module.

Link: https://lore.kernel.org/r/20210724072033.1284840-15-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

5 files changed, 120 insertions, 1 deletions

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 8f44d433e06e..86ecab196dfd 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -20,6 +20,7 @@ config SCSI
 	select SCSI_DMA if HAS_DMA
 	select SG_POOL
 	select BLK_SCSI_REQUEST
+	select BLK_DEV_BSG_COMMON if BLK_DEV_BSG
 	help
 	  If you want to use a SCSI hard disk, SCSI tape drive, SCSI CD-ROM or
 	  any other SCSI device under Linux, say Y and make sure that you know
@@ -140,6 +141,18 @@ config CHR_DEV_SG
 
 	  If unsure, say N.
 
+config BLK_DEV_BSG
+	bool "/dev/bsg support (SG v4)"
+	depends on SCSI
+	default y
+	help
+	  Saying Y here will enable generic SG (SCSI generic) v4 support
+	  for any SCSI device.
+
+	  This option is required by UDEV to access device serial numbers, etc.
+
+	  If unsure, say Y.
+
 config CHR_DEV_SCH
 	tristate "SCSI media changer support"
 	depends on SCSI
diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 1748d1ec1338..240b831b5a11 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -168,6 +168,7 @@ scsi_mod-$(CONFIG_BLK_DEBUG_FS)	+= scsi_debugfs.o
 scsi_mod-y			+= scsi_trace.o scsi_logging.o
 scsi_mod-$(CONFIG_PM)		+= scsi_pm.o
 scsi_mod-$(CONFIG_SCSI_DH)	+= scsi_dh.o
+scsi_mod-$(CONFIG_BLK_DEV_BSG)	+= scsi_bsg.o
 
 hv_storvsc-y			:= storvsc_drv.o
 
diff --git a/drivers/scsi/scsi_bsg.c b/drivers/scsi/scsi_bsg.c
new file mode 100644
index 000000000000..3bdb28940460
--- /dev/null
+++ b/drivers/scsi/scsi_bsg.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bsg.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/sg.h>
+#include "scsi_priv.h"
+
+#define uptr64(val) ((void __user *)(uintptr_t)(val))
+
+static int scsi_bsg_check_proto(struct sg_io_v4 *hdr)
+{
+	if (hdr->protocol != BSG_PROTOCOL_SCSI  ||
+	    hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
+		return -EINVAL;
+	return 0;
+}
+
+static int scsi_bsg_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
+		fmode_t mode)
+{
+	struct scsi_request *sreq = scsi_req(rq);
+
+	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+		pr_warn_once("BIDI support in bsg has been removed.\n");
+		return -EOPNOTSUPP;
+	}
+
+	sreq->cmd_len = hdr->request_len;
+	if (sreq->cmd_len > BLK_MAX_CDB) {
+		sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
+		if (!sreq->cmd)
+			return -ENOMEM;
+	}
+
+	if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
+		return -EFAULT;
+	if (blk_verify_command(sreq->cmd, mode))
+		return -EPERM;
+	return 0;
+}
+
+static int scsi_bsg_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
+{
+	struct scsi_request *sreq = scsi_req(rq);
+	int ret = 0;
+
+	/*
+	 * fill in all the output members
+	 */
+	hdr->device_status = sreq->result & 0xff;
+	hdr->transport_status = host_byte(sreq->result);
+	hdr->driver_status = 0;
+	if (scsi_status_is_check_condition(sreq->result))
+		hdr->driver_status = DRIVER_SENSE;
+	hdr->info = 0;
+	if (hdr->device_status || hdr->transport_status || hdr->driver_status)
+		hdr->info |= SG_INFO_CHECK;
+	hdr->response_len = 0;
+
+	if (sreq->sense_len && hdr->response) {
+		int len = min_t(unsigned int, hdr->max_response_len,
+					sreq->sense_len);
+
+		if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
+			ret = -EFAULT;
+		else
+			hdr->response_len = len;
+	}
+
+	if (rq_data_dir(rq) == READ)
+		hdr->din_resid = sreq->resid_len;
+	else
+		hdr->dout_resid = sreq->resid_len;
+
+	return ret;
+}
+
+static void scsi_bsg_free_rq(struct request *rq)
+{
+	scsi_req_free_cmd(scsi_req(rq));
+}
+
+static const struct bsg_ops scsi_bsg_ops = {
+	.check_proto		= scsi_bsg_check_proto,
+	.fill_hdr		= scsi_bsg_fill_hdr,
+	.complete_rq		= scsi_bsg_complete_rq,
+	.free_rq		= scsi_bsg_free_rq,
+};
+
+int scsi_bsg_register_queue(struct request_queue *q, struct device *parent)
+{
+	return bsg_register_queue(q, parent, dev_name(parent), &scsi_bsg_ops);
+}
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index eae2235f79b5..0a0db35bab04 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -180,6 +180,16 @@ static inline void scsi_dh_add_device(struct scsi_device *sdev) { }
 static inline void scsi_dh_release_device(struct scsi_device *sdev) { }
 #endif
 
+#ifdef CONFIG_BLK_DEV_BSG
+int scsi_bsg_register_queue(struct request_queue *q, struct device *parent);
+#else
+static inline int scsi_bsg_register_queue(struct request_queue *q,
+		struct device *parent)
+{
+	return 0;
+}
+#endif
+
 extern int scsi_device_max_queue_depth(struct scsi_device *sdev);
 
 /* 
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 32489d25158f..4ff9ac3296d8 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1366,7 +1366,7 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 	transport_add_device(&sdev->sdev_gendev);
 	sdev->is_visible = 1;
 
-	error = bsg_scsi_register_queue(rq, &sdev->sdev_gendev);
+	error = scsi_bsg_register_queue(rq, &sdev->sdev_gendev);
 	if (error)
 		/* we're treating error on bsg register as non-fatal,
 		 * so pretend nothing went wrong */