Further to a January 2013 thread titled: "[PATCH] SG_SCSI_RESET ioctl
should only perform requested operation" by Jeremy Linton a patch (v3)
is presented that expands the existing ioctl to include "no_escalate"
versions to the existing resets. This requires no changes to SCSI low
level drivers (LLDs); it adds several more finely tuned reset options
to the user space. For example:
/* This call remains the same, with the same escalating semantics
* if the device (LU) reset fail. That is: on failure to try a
* target reset and if that fails, try a bus reset, and if that fails
* try a host (i.e. LLD) reset. */
val = SG_SCSI_RESET_DEVICE;
res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val);
/* What follows is a new option introduced by this patch series. Only
* a device reset is attempted. If that fails then an appropriate
* error code is provided. N.B. There is no reset escalation. */
val = SG_SCSI_RESET_DEVICE | SG_SCSI_RESET_NO_ESCALATE;
res = ioctl(<sg_or_block_fd>, SG_SCSI_RESET, &val);
This patches applies to lk 3.17.0 and Christoph's drivers-for-3.18
tree. The sg_reset utility has been extended to use this new option
since sg3_utils-1.36 package which was released on 20130531.
v3 of this patch changes adding, subtracting and arithmetic
comparisons to the corresponding bitwise logical operations.
For example 'SG_SCSI_RESET_DEVICE + SG_SCSI_RESET_NO_ESCALATE' has
been changed to 'SG_SCSI_RESET_DEVICE | SG_SCSI_RESET_NO_ESCALATE'.
ChangeLog:
- modify SG_SCSI_RESET ioctl so the SG_SCSI_RESET_NO_ESCALATE
value may be OR-ed to the existing values. If so the existing
device->target->bus->host escalation does not occur. The
SG_SCSI_RESET ioctl is modified in both the sg driver and
scsi_ioctl.c (so block devices can use it).
- modify scsi_reset_provider() in the scsi_error.c file in a
similar way to support this additional functionality.
Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 6b20ef3..1338479 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -2362,8 +2362,18 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_HOST:
+ case SCSI_TRY_RESET_HOST | SCSI_TRY_RESET_NO_ESCALATE:
rtn = scsi_try_host_reset(scmd);
break;
+ case SCSI_TRY_RESET_DEVICE | SCSI_TRY_RESET_NO_ESCALATE:
+ rtn = scsi_try_bus_device_reset(scmd);
+ break;
+ case SCSI_TRY_RESET_TARGET | SCSI_TRY_RESET_NO_ESCALATE:
+ rtn = scsi_try_target_reset(scmd);
+ break;
+ case SCSI_TRY_RESET_BUS | SCSI_TRY_RESET_NO_ESCALATE:
+ rtn = scsi_try_bus_reset(scmd);
+ break;
default:
rtn = FAILED;
}
diff --git a/drivers/scsi/scsi_ioctl.c b/drivers/scsi/scsi_ioctl.c
index 1aaaf43..12fe676 100644
--- a/drivers/scsi/scsi_ioctl.c
+++ b/drivers/scsi/scsi_ioctl.c
@@ -285,13 +285,14 @@ EXPORT_SYMBOL(scsi_ioctl);
* scsi_nonblockable_ioctl() - Handle SG_SCSI_RESET
* @sdev: scsi device receiving ioctl
* @cmd: Must be SC_SCSI_RESET
- * @arg: pointer to int containing SG_SCSI_RESET_{DEVICE,BUS,HOST}
+ * @arg: pointer to int containing SG_SCSI_RESET_{DEVICE,TARGET,BUS,HOST}
+ * possibly OR-ed with SG_SCSI_RESET_NO_ESCALATE
* @ndelay: file mode O_NDELAY flag
*/
int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
void __user *arg, int ndelay)
{
- int val, result;
+ int val, val2, result;
/* The first set of iocts may be executed even if we're doing
* error processing, as long as the device was opened
@@ -307,27 +308,32 @@ int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
result = get_user(val, (int __user *)arg);
if (result)
return result;
+ if (val & SG_SCSI_RESET_NO_ESCALATE) {
+ val &= ~SG_SCSI_RESET_NO_ESCALATE;
+ val2 = SCSI_TRY_RESET_NO_ESCALATE;
+ } else
+ val2 = 0;
if (val == SG_SCSI_RESET_NOTHING)
return 0;
switch (val) {
case SG_SCSI_RESET_DEVICE:
- val = SCSI_TRY_RESET_DEVICE;
+ val2 |= SCSI_TRY_RESET_DEVICE;
break;
case SG_SCSI_RESET_TARGET:
- val = SCSI_TRY_RESET_TARGET;
+ val2 |= SCSI_TRY_RESET_TARGET;
break;
case SG_SCSI_RESET_BUS:
- val = SCSI_TRY_RESET_BUS;
+ val2 |= SCSI_TRY_RESET_BUS;
break;
case SG_SCSI_RESET_HOST:
- val = SCSI_TRY_RESET_HOST;
+ val2 |= SCSI_TRY_RESET_HOST;
break;
default:
return -EINVAL;
}
if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
return -EACCES;
- return (scsi_reset_provider(sdev, val) ==
+ return (scsi_reset_provider(sdev, val2) ==
SUCCESS) ? 0 : -EIO;
}
return -ENODEV;
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 01cf888..8345fab 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -847,7 +847,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
void __user *p = (void __user *)arg;
int __user *ip = p;
- int result, val, read_only;
+ int result, val, val2, read_only;
Sg_device *sdp;
Sg_fd *sfp;
Sg_request *srp;
@@ -1082,27 +1082,32 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
result = get_user(val, ip);
if (result)
return result;
+ if (val & SG_SCSI_RESET_NO_ESCALATE) {
+ val &= ~SG_SCSI_RESET_NO_ESCALATE;
+ val2 = SCSI_TRY_RESET_NO_ESCALATE;
+ } else
+ val2 = 0;
if (SG_SCSI_RESET_NOTHING == val)
return 0;
switch (val) {
case SG_SCSI_RESET_DEVICE:
- val = SCSI_TRY_RESET_DEVICE;
+ val2 |= SCSI_TRY_RESET_DEVICE;
break;
case SG_SCSI_RESET_TARGET:
- val = SCSI_TRY_RESET_TARGET;
+ val2 |= SCSI_TRY_RESET_TARGET;
break;
case SG_SCSI_RESET_BUS:
- val = SCSI_TRY_RESET_BUS;
+ val2 |= SCSI_TRY_RESET_BUS;
break;
case SG_SCSI_RESET_HOST:
- val = SCSI_TRY_RESET_HOST;
+ val2 |= SCSI_TRY_RESET_HOST;
break;
default:
return -EINVAL;
}
if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
return -EACCES;
- return (scsi_reset_provider(sdp->device, val) ==
+ return (scsi_reset_provider(sdp->device, val2) ==
SUCCESS) ? 0 : -EIO;
case SCSI_IOCTL_SEND_COMMAND:
if (atomic_read(&sdp->detaching))
diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
index 06a8790..49af14a 100644
--- a/include/scsi/scsi_eh.h
+++ b/include/scsi/scsi_eh.h
@@ -62,11 +62,16 @@ extern void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq);
/*
* Reset request from external source
+ * Note: if SCSI_TRY_RESET_DEVICE fails then it will escalate to
+ * SCSI_TRY_RESET_TARGET which if it fails will escalate to
+ * SCSI_TRY_RESET_BUS which if it fails will escalate to SCSI_TRY_RESET_HOST.
+ * To prevent escalation OR with SCSI_TRY_RESET_NO_ESCALATE.
*/
#define SCSI_TRY_RESET_DEVICE 1
#define SCSI_TRY_RESET_BUS 2
#define SCSI_TRY_RESET_HOST 3
#define SCSI_TRY_RESET_TARGET 4
+#define SCSI_TRY_RESET_NO_ESCALATE 0x100 /* OR-ed to prior defines */
extern int scsi_reset_provider(struct scsi_device *, int);
diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index 750e5db..3afec70 100644
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -164,12 +164,15 @@ typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
/* Returns -EBUSY if occupied. 3rd argument pointer to int (see next) */
#define SG_SCSI_RESET 0x2284
-/* Associated values that can be given to SG_SCSI_RESET follow */
+/* Associated values that can be given to SG_SCSI_RESET follow.
+ * SG_SCSI_RESET_NO_ESCALATE may be OR-ed to the _DEVICE, _TARGET, _BUS
+ * or _HOST reset value so only that action is attempted. */
#define SG_SCSI_RESET_NOTHING 0
#define SG_SCSI_RESET_DEVICE 1
#define SG_SCSI_RESET_BUS 2
#define SG_SCSI_RESET_HOST 3
#define SG_SCSI_RESET_TARGET 4
+#define SG_SCSI_RESET_NO_ESCALATE 0x100
/* synchronous SCSI command ioctl, (only in version 3 interface) */
#define SG_IO 0x2285 /* similar effect as write() followed by read() */
