[PATCH] libata: separate out rw ATA taskfile building into ata_build_rw_tf()

Separate out rw ATA taskfile building from ata_scsi_rw_xlat() into
ata_build_rw_tf().  This will be used to improve media error handling.

Signed-off-by: Tejun Heo <htejun@gmail.com>

3 files changed, 145 insertions, 112 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 0a5103b707c6..4ac53ef0e4b0 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -199,7 +199,8 @@ static const u8 ata_rw_cmds[] = {
 
 /**
  *      ata_rwcmd_protocol - set taskfile r/w commands and protocol
- *      @qc: command to examine and configure
+ *      @tf: command to examine and configure
+ *      @dev: device tf belongs to
  *
  *      Examine the device configuration and tf->flags to calculate
  *      the proper read/write commands and protocol to use.
@@ -207,10 +208,8 @@ static const u8 ata_rw_cmds[] = {
  *      LOCKING:
  *      caller.
  */
-int ata_rwcmd_protocol(struct ata_queued_cmd *qc)
+static int ata_rwcmd_protocol(struct ata_taskfile *tf, struct ata_device *dev)
 {
-        struct ata_taskfile *tf = &qc->tf;
-        struct ata_device *dev = qc->dev;
         u8 cmd;
 
         int index, fua, lba48, write;
@@ -222,7 +221,7 @@ int ata_rwcmd_protocol(struct ata_queued_cmd *qc)
         if (dev->flags & ATA_DFLAG_PIO) {
                 tf->protocol = ATA_PROT_PIO;
                 index = dev->multi_count ? 0 : 8;
-        } else if (lba48 && (qc->ap->flags & ATA_FLAG_PIO_LBA48)) {
+        } else if (lba48 && (dev->ap->flags & ATA_FLAG_PIO_LBA48)) {
                 /* Unable to use DMA due to host limitation */
                 tf->protocol = ATA_PROT_PIO;
                 index = dev->multi_count ? 0 : 8;
@@ -283,6 +282,130 @@ u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev)
 }
 
 /**
+ *      ata_build_rw_tf - Build ATA taskfile for given read/write request
+ *      @tf: Target ATA taskfile
+ *      @dev: ATA device @tf belongs to
+ *      @block: Block address
+ *      @n_block: Number of blocks
+ *      @tf_flags: RW/FUA etc...
+ *      @tag: tag
+ *
+ *      LOCKING:
+ *      None.
+ *
+ *      Build ATA taskfile @tf for read/write request described by
+ *      @block, @n_block, @tf_flags and @tag on @dev.
+ *
+ *      RETURNS:
+ *
+ *      0 on success, -ERANGE if the request is too large for @dev,
+ *      -EINVAL if the request is invalid.
+ */
+int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
+                    u64 block, u32 n_block, unsigned int tf_flags,
+                    unsigned int tag)
+{
+        tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+        tf->flags |= tf_flags;
+
+        if ((dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ_OFF |
+                           ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ) {
+                /* yay, NCQ */
+                if (!lba_48_ok(block, n_block))
+                        return -ERANGE;
+
+                tf->protocol = ATA_PROT_NCQ;
+                tf->flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
+
+                if (tf->flags & ATA_TFLAG_WRITE)
+                        tf->command = ATA_CMD_FPDMA_WRITE;
+                else
+                        tf->command = ATA_CMD_FPDMA_READ;
+
+                tf->nsect = tag << 3;
+                tf->hob_feature = (n_block >> 8) & 0xff;
+                tf->feature = n_block & 0xff;
+
+                tf->hob_lbah = (block >> 40) & 0xff;
+                tf->hob_lbam = (block >> 32) & 0xff;
+                tf->hob_lbal = (block >> 24) & 0xff;
+                tf->lbah = (block >> 16) & 0xff;
+                tf->lbam = (block >> 8) & 0xff;
+                tf->lbal = block & 0xff;
+
+                tf->device = 1 << 6;
+                if (tf->flags & ATA_TFLAG_FUA)
+                        tf->device |= 1 << 7;
+        } else if (dev->flags & ATA_DFLAG_LBA) {
+                tf->flags |= ATA_TFLAG_LBA;
+
+                if (lba_28_ok(block, n_block)) {
+                        /* use LBA28 */
+                        tf->device |= (block >> 24) & 0xf;
+                } else if (lba_48_ok(block, n_block)) {
+                        if (!(dev->flags & ATA_DFLAG_LBA48))
+                                return -ERANGE;
+
+                        /* use LBA48 */
+                        tf->flags |= ATA_TFLAG_LBA48;
+
+                        tf->hob_nsect = (n_block >> 8) & 0xff;
+
+                        tf->hob_lbah = (block >> 40) & 0xff;
+                        tf->hob_lbam = (block >> 32) & 0xff;
+                        tf->hob_lbal = (block >> 24) & 0xff;
+                } else
+                        /* request too large even for LBA48 */
+                        return -ERANGE;
+
+                if (unlikely(ata_rwcmd_protocol(tf, dev) < 0))
+                        return -EINVAL;
+
+                tf->nsect = n_block & 0xff;
+
+                tf->lbah = (block >> 16) & 0xff;
+                tf->lbam = (block >> 8) & 0xff;
+                tf->lbal = block & 0xff;
+
+                tf->device |= ATA_LBA;
+        } else {
+                /* CHS */
+                u32 sect, head, cyl, track;
+
+                /* The request -may- be too large for CHS addressing. */
+                if (!lba_28_ok(block, n_block))
+                        return -ERANGE;
+
+                if (unlikely(ata_rwcmd_protocol(tf, dev) < 0))
+                        return -EINVAL;
+
+                /* Convert LBA to CHS */
+                track = (u32)block / dev->sectors;
+                cyl   = track / dev->heads;
+                head  = track % dev->heads;
+                sect  = (u32)block % dev->sectors + 1;
+
+                DPRINTK("block %u track %u cyl %u head %u sect %u\n",
+                        (u32)block, track, cyl, head, sect);
+
+                /* Check whether the converted CHS can fit.
+                   Cylinder: 0-65535
+                   Head: 0-15
+                   Sector: 1-255*/
+                if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
+                        return -ERANGE;
+
+                tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
+                tf->lbal = sect;
+                tf->lbam = cyl;
+                tf->lbah = cyl >> 8;
+                tf->device |= head;
+        }
+
+        return 0;
+}
+
+/**
  *      ata_pack_xfermask - Pack pio, mwdma and udma masks into xfer_mask
  *      @pio_mask: pio_mask
  *      @mwdma_mask: mwdma_mask
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index d250858d201c..8eaace94d963 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1265,17 +1265,14 @@ nothing_to_do:
 
 static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, const u8 *scsicmd)
 {
-        struct ata_taskfile *tf = &qc->tf;
-        struct ata_device *dev = qc->dev;
+        unsigned int tf_flags = 0;
         u64 block;
         u32 n_block;
-
-        qc->flags |= ATA_QCFLAG_IO;
-        tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+        int rc;
 
         if (scsicmd[0] == WRITE_10 || scsicmd[0] == WRITE_6 ||
             scsicmd[0] == WRITE_16)
-                tf->flags |= ATA_TFLAG_WRITE;
+                tf_flags |= ATA_TFLAG_WRITE;
 
         /* Calculate the SCSI LBA, transfer length and FUA. */
         switch (scsicmd[0]) {
@@ -1283,7 +1280,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, const u8 *scsicm
         case WRITE_10:
                 scsi_10_lba_len(scsicmd, &block, &n_block);
                 if (unlikely(scsicmd[1] & (1 << 3)))
-                        tf->flags |= ATA_TFLAG_FUA;
+                        tf_flags |= ATA_TFLAG_FUA;
                 break;
         case READ_6:
         case WRITE_6:
@@ -1299,7 +1296,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, const u8 *scsicm
         case WRITE_16:
                 scsi_16_lba_len(scsicmd, &block, &n_block);
                 if (unlikely(scsicmd[1] & (1 << 3)))
-                        tf->flags |= ATA_TFLAG_FUA;
+                        tf_flags |= ATA_TFLAG_FUA;
                 break;
         default:
                 DPRINTK("no-byte command\n");
@@ -1317,106 +1314,17 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, const u8 *scsicm
                  */
                 goto nothing_to_do;
 
-        if ((dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ_OFF |
-                           ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ) {
-                /* yay, NCQ */
-                if (!lba_48_ok(block, n_block))
-                        goto out_of_range;
-
-                tf->protocol = ATA_PROT_NCQ;
-                tf->flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
-
-                if (tf->flags & ATA_TFLAG_WRITE)
-                        tf->command = ATA_CMD_FPDMA_WRITE;
-                else
-                        tf->command = ATA_CMD_FPDMA_READ;
-
-                qc->nsect = n_block;
-
-                tf->nsect = qc->tag << 3;
-                tf->hob_feature = (n_block >> 8) & 0xff;
-                tf->feature = n_block & 0xff;
-
-                tf->hob_lbah = (block >> 40) & 0xff;
-                tf->hob_lbam = (block >> 32) & 0xff;
-                tf->hob_lbal = (block >> 24) & 0xff;
-                tf->lbah = (block >> 16) & 0xff;
-                tf->lbam = (block >> 8) & 0xff;
-                tf->lbal = block & 0xff;
-
-                tf->device = 1 << 6;
-                if (tf->flags & ATA_TFLAG_FUA)
-                        tf->device |= 1 << 7;
-        } else if (dev->flags & ATA_DFLAG_LBA) {
-                tf->flags |= ATA_TFLAG_LBA;
-
-                if (lba_28_ok(block, n_block)) {
-                        /* use LBA28 */
-                        tf->device |= (block >> 24) & 0xf;
-                } else if (lba_48_ok(block, n_block)) {
-                        if (!(dev->flags & ATA_DFLAG_LBA48))
-                                goto out_of_range;
-
-                        /* use LBA48 */
-                        tf->flags |= ATA_TFLAG_LBA48;
-
-                        tf->hob_nsect = (n_block >> 8) & 0xff;
-
-                        tf->hob_lbah = (block >> 40) & 0xff;
-                        tf->hob_lbam = (block >> 32) & 0xff;
-                        tf->hob_lbal = (block >> 24) & 0xff;
-                } else
-                        /* request too large even for LBA48 */
-                        goto out_of_range;
-
-                if (unlikely(ata_rwcmd_protocol(qc) < 0))
-                        goto invalid_fld;
-
-                qc->nsect = n_block;
-                tf->nsect = n_block & 0xff;
-
-                tf->lbah = (block >> 16) & 0xff;
-                tf->lbam = (block >> 8) & 0xff;
-                tf->lbal = block & 0xff;
-
-                tf->device |= ATA_LBA;
-        } else {
-                /* CHS */
-                u32 sect, head, cyl, track;
-
-                /* The request -may- be too large for CHS addressing. */
-                if (!lba_28_ok(block, n_block))
-                        goto out_of_range;
-
-                if (unlikely(ata_rwcmd_protocol(qc) < 0))
-                        goto invalid_fld;
-
-                /* Convert LBA to CHS */
-                track = (u32)block / dev->sectors;
-                cyl   = track / dev->heads;
-                head  = track % dev->heads;
-                sect  = (u32)block % dev->sectors + 1;
-
-                DPRINTK("block %u track %u cyl %u head %u sect %u\n",
-                        (u32)block, track, cyl, head, sect);
-
-                /* Check whether the converted CHS can fit.
-                   Cylinder: 0-65535
-                   Head: 0-15
-                   Sector: 1-255*/
-                if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
-                        goto out_of_range;
-
-                qc->nsect = n_block;
-                tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
-                tf->lbal = sect;
-                tf->lbam = cyl;
-                tf->lbah = cyl >> 8;
-                tf->device |= head;
-        }
+        qc->flags |= ATA_QCFLAG_IO;
+        qc->nsect = n_block;
 
-        return 0;
+        rc = ata_build_rw_tf(&qc->tf, qc->dev, block, n_block, tf_flags,
+                             qc->tag);
+        if (likely(rc == 0))
+                return 0;
 
+        if (rc == -ERANGE)
+                goto out_of_range;
+        /* treat all other errors as -EINVAL, fall through */
 invalid_fld:
         ata_scsi_set_sense(qc->scsicmd, ILLEGAL_REQUEST, 0x24, 0x0);
         /* "Invalid field in cbd" */
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index ca6f36c13115..60576b1237e4 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -51,7 +51,9 @@ extern int atapi_enabled;
 extern int atapi_dmadir;
 extern int libata_fua;
 extern struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev);
-extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);
+extern int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
+                           u64 block, u32 n_block, unsigned int tf_flags,
+                           unsigned int tag);
 extern u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev);
 extern void ata_dev_disable(struct ata_device *dev);
 extern void ata_port_flush_task(struct ata_port *ap);