[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: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index e3bda07..7c2dead 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -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

diff --git a/drivers/firewire/sbp2.c b/drivers/firewire/sbp2.c
index 1162d6b..f82e9d4 100644 (file)
--- a/drivers/firewire/sbp2.c
+++ b/drivers/firewire/sbp2.c
@@ -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;

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 2936b44..2c0d0ec 100644 (file)
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -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>
@@ -1062,6 +1063,50 @@ 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
  *

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index a3d5436..6ab376a 100644 (file)
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -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. */

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 88fae8d..379d465 100644 (file)
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -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,