libata: implement ata_qc_raw_nbytes()
Implement ata_qc_raw_nbytes() which determines the raw user-requested
size of a PC command.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 8f0e8f2..1579539 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -527,6 +527,14 @@
return qc;
}
+static void ata_qc_set_pc_nbytes(struct ata_queued_cmd *qc)
+{
+ struct scsi_cmnd *scmd = qc->scsicmd;
+
+ qc->extrabytes = scmd->request->extra_len;
+ qc->nbytes = scsi_bufflen(scmd) + qc->extrabytes;
+}
+
/**
* ata_dump_status - user friendly display of error info
* @id: id of the port in question
@@ -2539,7 +2547,7 @@
}
qc->tf.command = ATA_CMD_PACKET;
- qc->nbytes = scsi_bufflen(scmd) + scmd->request->extra_len;
+ ata_qc_set_pc_nbytes(qc);
/* check whether ATAPI DMA is safe */
if (!using_pio && ata_check_atapi_dma(qc))
@@ -2550,7 +2558,7 @@
* want to set it properly, and for DMA where it is
* effectively meaningless.
*/
- nbytes = min(scmd->request->data_len, (unsigned int)63 * 1024);
+ nbytes = min(ata_qc_raw_nbytes(qc), (unsigned int)63 * 1024);
/* Most ATAPI devices which honor transfer chunk size don't
* behave according to the spec when odd chunk size which
@@ -2876,7 +2884,7 @@
* TODO: find out if we need to do more here to
* cover scatter/gather case.
*/
- qc->nbytes = scsi_bufflen(scmd) + scmd->request->extra_len;
+ ata_qc_set_pc_nbytes(qc);
/* request result TF and be quiet about device error */
qc->flags |= ATA_QCFLAG_RESULT_TF | ATA_QCFLAG_QUIET;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a05f600..269cdba 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -463,6 +463,7 @@
unsigned int sect_size;
unsigned int nbytes;
+ unsigned int extrabytes;
unsigned int curbytes;
struct scatterlist *cursg;
@@ -1336,6 +1337,11 @@
return NULL;
}
+static inline unsigned int ata_qc_raw_nbytes(struct ata_queued_cmd *qc)
+{
+ return qc->nbytes - min(qc->extrabytes, qc->nbytes);
+}
+
static inline void ata_tf_init(struct ata_device *dev, struct ata_taskfile *tf)
{
memset(tf, 0, sizeof(*tf));
@@ -1354,7 +1360,7 @@
qc->flags = 0;
qc->cursg = NULL;
qc->cursg_ofs = 0;
- qc->nbytes = qc->curbytes = 0;
+ qc->nbytes = qc->extrabytes = qc->curbytes = 0;
qc->n_elem = 0;
qc->err_mask = 0;
qc->sect_size = ATA_SECT_SIZE;