[PATCH v24 31/46] sg: add sg_iosubmit_v3 and sg_ioreceive_v3 ioctls

Douglas Gilbert
2022-04-11T02:30:43Z

Add ioctl(SG_IOSUBMIT_V3) and ioctl(SG_IORECEIVE_V3). These ioctls
are meant to be (almost) drop-in replacements for the write()/read()
async version 3 interface. They only accept the version 3 interface.

See the webpage at: https://sg.danny.cz/sg/sg_v40.html
specifically the table in the section titled: "13 SG interface
support changes".

If sgv3 is a struct sg_io_hdr object, suitably configured, then
res = write(sg_fd, &sgv3, sizeof(sgv3));
and
res = ioctl(sg_fd, SG_IOSUBMIT_V3, &sgv3);
are equivalent. Dito for read() and ioctl(SG_IORECEIVE_V3).

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
---
drivers/scsi/sg.c | 76 ++++++++++++++++++++++++++++++++++++++++++
include/uapi/scsi/sg.h | 6 ++++
2 files changed, 82 insertions(+)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 5df79e5fc6d5..812767d50c31 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -834,6 +834,24 @@ sg_ctl_iosubmit(struct file *filp, struct sg_fd *sfp, void __user *p)
return -EPERM;
}

+static int
+sg_ctl_iosubmit_v3(struct file *filp, struct sg_fd *sfp, void __user *p)
+{
+ int res;
+ u8 hdr_store[SZ_SG_IO_V4]; /* max(v3interface, v4interface) */
+ struct sg_io_hdr *h3p = (struct sg_io_hdr *)hdr_store;
+ struct sg_device *sdp = sfp->parentdp;
+
+ res = sg_allow_if_err_recovery(sdp, (filp->f_flags & O_NONBLOCK));
+ if (unlikely(res))
+ return res;
+ if (copy_from_user(h3p, p, SZ_SG_IO_HDR))
+ return -EFAULT;
+ if (h3p->interface_id == 'S')
+ return sg_v3_submit(filp, sfp, h3p, false, NULL);
+ return -EPERM;
+}
+
#if IS_ENABLED(SG_LOG_ACTIVE)
static void
sg_rq_state_fail_msg(struct sg_fd *sfp, enum sg_rq_state exp_old_st,
@@ -1156,6 +1174,7 @@ sg_receive_v3(struct sg_fd *sfp, struct sg_request *srp, size_t count,
hp->sb_len_wr = srp->sense_len;
hp->info = srp->rq_info;
hp->resid = srp->in_resid;
+ hp->pack_id = srp->pack_id;
hp->duration = srp->duration;
hp->status = rq_result & 0xff;
hp->masked_status = status_byte(rq_result);
@@ -1271,6 +1290,57 @@ sg_ctl_ioreceive(struct file *filp, struct sg_fd *sfp, void __user *p)
return sg_receive_v4(sfp, srp, p, h4p);
}

+/*
+ * Called when ioctl(SG_IORECEIVE_V3) received. Expects a v3 interface.
+ * Checks if O_NONBLOCK file flag given, if not checks given flags field
+ * to see if SGV4_FLAG_IMMED is set. Either of these implies non blocking.
+ * When non-blocking and there is no request waiting, yields EAGAIN;
+ * otherwise it waits.
+ */
+static int
+sg_ctl_ioreceive_v3(struct file *filp, struct sg_fd *sfp, void __user *p)
+{
+ bool non_block = !!(filp->f_flags & O_NONBLOCK);
+ int res;
+ int pack_id = SG_PACK_ID_WILDCARD;
+ u8 v3_holder[SZ_SG_IO_HDR];
+ struct sg_io_hdr *h3p = (struct sg_io_hdr *)v3_holder;
+ struct sg_device *sdp = sfp->parentdp;
+ struct sg_request *srp;
+
+ res = sg_allow_if_err_recovery(sdp, non_block);
+ if (unlikely(res))
+ return res;
+ /* Get first three 32 bit integers: guard, proto+subproto */
+ if (copy_from_user(h3p, p, SZ_SG_IO_HDR))
+ return -EFAULT;
+ /* for v3: interface_id=='S' (in a 32 bit int) */
+ if (h3p->interface_id != 'S')
+ return -EPERM;
+ if (h3p->flags & SGV4_FLAG_IMMED)
+ non_block = true; /* set by either this or O_NONBLOCK */
+ SG_LOG(3, sfp, "%s: non_block(+IMMED)=%d\n", __func__, non_block);
+
+ if (test_bit(SG_FFD_FORCE_PACKID, sfp->ffd_bm))
+ pack_id = h3p->pack_id;
+
+ srp = sg_find_srp_by_id(sfp, pack_id);
+ if (!srp) { /* nothing available so wait on packet or */
+ if (unlikely(SG_IS_DETACHING(sdp)))
+ return -ENODEV;
+ if (non_block)
+ return -EAGAIN;
+ res = wait_event_interruptible
+ (sfp->read_wait,
+ sg_get_ready_srp(sfp, &srp, pack_id));
+ if (unlikely(SG_IS_DETACHING(sdp)))
+ return -ENODEV;
+ if (unlikely(res))
+ return res; /* signal --> -ERESTARTSYS */
+ } /* now srp should be valid */
+ return sg_receive_v3(sfp, srp, SZ_SG_IO_HDR, p);
+}
+
static int
sg_read_v1v2(void __user *buf, int count, struct sg_fd *sfp,
struct sg_request *srp)
@@ -1815,9 +1885,15 @@ sg_ioctl_common(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
case SG_IOSUBMIT:
SG_LOG(3, sfp, "%s: SG_IOSUBMIT\n", __func__);
return sg_ctl_iosubmit(filp, sfp, p);
+ case SG_IOSUBMIT_V3:
+ SG_LOG(3, sfp, "%s: SG_IOSUBMIT_V3\n", __func__);
+ return sg_ctl_iosubmit_v3(filp, sfp, p);
case SG_IORECEIVE:
SG_LOG(3, sfp, "%s: SG_IORECEIVE\n", __func__);
return sg_ctl_ioreceive(filp, sfp, p);
+ case SG_IORECEIVE_V3:
+ SG_LOG(3, sfp, "%s: SG_IORECEIVE_V3\n", __func__);
+ return sg_ctl_ioreceive_v3(filp, sfp, p);
case SG_GET_SCSI_ID:
return sg_ctl_scsi_id(sdev, sfp, p);
case SG_SET_FORCE_PACK_ID:
diff --git a/include/uapi/scsi/sg.h b/include/uapi/scsi/sg.h
index 1425b41b2d83..9060c40957f9 100644
--- a/include/uapi/scsi/sg.h
+++ b/include/uapi/scsi/sg.h
@@ -390,6 +390,12 @@ struct sg_header {
/* Gives some v4 identifying info to driver, receives associated response */
#define SG_IORECEIVE _IOWR(SG_IOCTL_MAGIC_NUM, 0x42, struct sg_io_v4)

+/* Submits a v3 interface object to driver */
+#define SG_IOSUBMIT_V3 _IOWR(SG_IOCTL_MAGIC_NUM, 0x45, struct sg_io_hdr)
+
+/* Gives some v3 identifying info to driver, receives associated response */
+#define SG_IORECEIVE_V3 _IOWR(SG_IOCTL_MAGIC_NUM, 0x46, struct sg_io_hdr)
+
/* command queuing is always on when the v3 or v4 interface is used */
#define SG_DEF_COMMAND_Q 0

--
2.25.1