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Commit 26cf591e authored by Douglas Gilbert's avatar Douglas Gilbert Committed by Christoph Hellwig
Browse files

scsi: add SG_SCSI_RESET_NO_ESCALATE flag to SG_SCSI_RESET ioctl 



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);

Signed-off-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: default avatarJeremy Linton <jlinton@tributary.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 678e2757

drivers/scsi/scsi_error.c

+10 −0
Original line number Diff line number Diff line
@@ -2366,8 +2366,18 @@ 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;

	}

drivers/scsi/scsi_ioctl.c

+13 −7
Original line number Diff line number Diff line
@@ -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;

drivers/scsi/sg.c

+11 −6
Original line number Diff line number Diff line
@@ -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))

include/scsi/scsi_eh.h

+5 −0
Original line number Diff line number Diff line
@@ -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);

include/scsi/sg.h

+4 −1
Original line number Diff line number Diff line
@@ -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() */