libata-scsi: ata_task_ioctl should return ATA registers from sense data

User applications using the HDIO_DRIVE_TASK ioctl through libata expect
specific ATA registers to be returned to userspace.  Verified that
ata_task_ioctl correctly returns register values to the smartctl
application.

Signed-off-by: David Milburn <dmilburn@redhat.com>
Acked-by: Tejun Heo <htejun@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 45 insertions, 6 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7cc5a4a910a4..d151cf057ef2 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -273,8 +273,8 @@ int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg)
 {
         int rc = 0;
         u8 scsi_cmd[MAX_COMMAND_SIZE];
-        u8 args[7];
-        struct scsi_sense_hdr sshdr;
+        u8 args[7], *sensebuf = NULL;
+        int cmd_result;
 
         if (arg == NULL)
                 return -EINVAL;
@@ -282,10 +282,14 @@ int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg)
         if (copy_from_user(args, arg, sizeof(args)))
                 return -EFAULT;
 
+        sensebuf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
+        if (!sensebuf)
+                return -ENOMEM;
+
         memset(scsi_cmd, 0, sizeof(scsi_cmd));
         scsi_cmd[0]  = ATA_16;
         scsi_cmd[1]  = (3 << 1); /* Non-data */
-        /* scsi_cmd[2] is already 0 -- no off.line, cc, or data xfer */
+        scsi_cmd[2]  = 0x20;     /* cc but no off.line or data xfer */
         scsi_cmd[4]  = args[1];
         scsi_cmd[6]  = args[2];
         scsi_cmd[8]  = args[3];
@@ -295,11 +299,46 @@ int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg)
 
         /* Good values for timeout and retries?  Values below
            from scsi_ioctl_send_command() for default case... */
-        if (scsi_execute_req(scsidev, scsi_cmd, DMA_NONE, NULL, 0, &sshdr,
-                             (10*HZ), 5))
+        cmd_result = scsi_execute(scsidev, scsi_cmd, DMA_NONE, NULL, 0,
+                                sensebuf, (10*HZ), 5, 0);
+
+        if (driver_byte(cmd_result) == DRIVER_SENSE) {/* sense data available */
+                u8 *desc = sensebuf + 8;
+                cmd_result &= ~(0xFF<<24); /* DRIVER_SENSE is not an error */
+
+                /* If we set cc then ATA pass-through will cause a
+                 * check condition even if no error. Filter that. */
+                if (cmd_result & SAM_STAT_CHECK_CONDITION) {
+                        struct scsi_sense_hdr sshdr;
+                        scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE,
+                                                &sshdr);
+                        if (sshdr.sense_key==0 &&
+                                sshdr.asc==0 && sshdr.ascq==0)
+                                cmd_result &= ~SAM_STAT_CHECK_CONDITION;
+                }
+
+                /* Send userspace ATA registers */
+                if (sensebuf[0] == 0x72 &&      /* format is "descriptor" */
+                                desc[0] == 0x09) {/* code is "ATA Descriptor" */
+                        args[0] = desc[13];     /* status */
+                        args[1] = desc[3];      /* error */
+                        args[2] = desc[5];      /* sector count (0:7) */
+                        args[3] = desc[7];      /* lbal */
+                        args[4] = desc[9];      /* lbam */
+                        args[5] = desc[11];     /* lbah */
+                        args[6] = desc[12];     /* select */
+                        if (copy_to_user(arg, args, sizeof(args)))
+                                rc = -EFAULT;
+                }
+        }
+
+        if (cmd_result) {
                 rc = -EIO;
+                goto error;
+        }
 
-        /* Need code to retrieve data from check condition? */
+ error:
+        kfree(sensebuf);
         return rc;
 }