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

[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
......@@ -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
......
......@@ -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;
......
......@@ -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
......
......@@ -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. */
......
......@@ -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,
......
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