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Commit 3c6bdaea authored by Martin K. Petersen's avatar Martin K. Petersen Committed by James Bottomley
Browse files

[SCSI] Add a report opcode helper 



The REPORT SUPPORTED OPERATION CODES command can be used to query
whether a given opcode is supported by a device. Add a helper function
that allows us to look up commands.

We only issue RSOC if the device reports compliance with SPC-3 or
later. But to err on the side of caution we disable the command for ATA,
FireWire and USB.

Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 49bd665c

drivers/ata/libata-scsi.c

+1 −0
Original line number Diff line number Diff line
@@ -1052,6 +1052,7 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev) 
{

	sdev->use_10_for_rw = 1;

	sdev->use_10_for_ms = 1;

	sdev->no_report_opcodes = 1;



	/* Schedule policy is determined by ->qc_defer() callback and

	 * it needs to see every deferred qc.  Set dev_blocked to 1 to

drivers/firewire/sbp2.c

+1 −0
Original line number Diff line number Diff line
@@ -1546,6 +1546,7 @@ static int sbp2_scsi_slave_configure(struct scsi_device *sdev) 
	struct sbp2_logical_unit *lu = sdev->hostdata;



	sdev->use_10_for_rw = 1;

	sdev->no_report_opcodes = 1;



	if (sbp2_param_exclusive_login)

		sdev->manage_start_stop = 1;

drivers/scsi/scsi.c

+45 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ 
#include <linux/cpu.h>

#include <linux/mutex.h>

#include <linux/async.h>

#include <asm/unaligned.h>



#include <scsi/scsi.h>

#include <scsi/scsi_cmnd.h>
@@ -1061,6 +1062,50 @@ int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 
}

EXPORT_SYMBOL_GPL(scsi_get_vpd_page);



/**

 * scsi_report_opcode - Find out if a given command opcode is supported

 * @sdev:	scsi device to query

 * @buffer:	scratch buffer (must be at least 20 bytes long)

 * @len:	length of buffer

 * @opcode:	opcode for command to look up

 *

 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given

 * opcode. Returns 0 if RSOC fails or if the command opcode is

 * unsupported. Returns 1 if the device claims to support the command.

 */

int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,

		       unsigned int len, unsigned char opcode)

{

	unsigned char cmd[16];

	struct scsi_sense_hdr sshdr;

	int result;



	if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)

		return 0;



	memset(cmd, 0, 16);

	cmd[0] = MAINTENANCE_IN;

	cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;

	cmd[2] = 1;		/* One command format */

	cmd[3] = opcode;

	put_unaligned_be32(len, &cmd[6]);

	memset(buffer, 0, len);



	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,

				  &sshdr, 30 * HZ, 3, NULL);



	if (result && scsi_sense_valid(&sshdr) &&

	    sshdr.sense_key == ILLEGAL_REQUEST &&

	    (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)

		return 0;



	if ((buffer[1] & 3) == 3) /* Command supported */

		return 1;



	return 0;

}

EXPORT_SYMBOL(scsi_report_opcode);



/**

 * scsi_device_get  -  get an additional reference to a scsi_device

 * @sdev:	device to get a reference to

drivers/usb/storage/scsiglue.c

+3 −0
Original line number Diff line number Diff line
@@ -186,6 +186,9 @@ static int slave_configure(struct scsi_device *sdev) 
		/* Some devices don't handle VPD pages correctly */

		sdev->skip_vpd_pages = 1;



		/* Do not attempt to use REPORT SUPPORTED OPERATION CODES */

		sdev->no_report_opcodes = 1;



		/* Some disks return the total number of blocks in response

		 * to READ CAPACITY rather than the highest block number.

		 * If this device makes that mistake, tell the sd driver. */

include/scsi/scsi_device.h

+3 −0
Original line number Diff line number Diff line
@@ -135,6 +135,7 @@ struct scsi_device { 
				     * because we did a bus reset. */

	unsigned use_10_for_rw:1; /* first try 10-byte read / write */

	unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */

	unsigned no_report_opcodes:1;	/* no REPORT SUPPORTED OPERATION CODES */

	unsigned skip_ms_page_8:1;	/* do not use MODE SENSE page 0x08 */

	unsigned skip_ms_page_3f:1;	/* do not use MODE SENSE page 0x3f */

	unsigned skip_vpd_pages:1;	/* do not read VPD pages */
@@ -362,6 +363,8 @@ extern int scsi_test_unit_ready(struct scsi_device *sdev, int timeout, 
				int retries, struct scsi_sense_hdr *sshdr);

extern int scsi_get_vpd_page(struct scsi_device *, u8 page, unsigned char *buf,

			     int buf_len);

extern int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,

			      unsigned int len, unsigned char opcode);

extern int scsi_device_set_state(struct scsi_device *sdev,

				 enum scsi_device_state state);

extern struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,