Hello, Douglas & Jeff.
This is preview implementation of multi-qc SCSI command translation.
New translation type 'sequence' is defined and handled by sat_task
running on ata_sat_wq. Rationale...
a. inside qc chaining as in sil m15w workaround is too hacky & fragile.
b. multi qc chaining without task is possible but, with thread...
- translation implementation is easier (simple contexts on
stack, easier code flow...)
- we are much less restriced in what we can do (in case full
SAT implementation requires something weird).
- this isn't a hot path, simplicity & maintainability weigh
more than performance.
Current implementation is broken in that each qc's completion status
cannot be acquired. This can be fixed by adding opaque user data
field to ->complete_fn and unifying ->waiting mechanism into
->complete_fn. If this task-based approach is okay with other ATA
developers, I'll do that and post splitted patches.
The following is one big patch containing multi-qc sequencing
infrastructure and stupid & broken MODE_SELECT_10 implementation.
msel10 implemented here only deals with WCE and DRA of caching mode
page. It's stupid but demonstrates enough, hopefully.
Thanks.
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3924,6 +3924,7 @@ static void ata_host_init(struct ata_por
INIT_WORK(&ap->packet_task, atapi_packet_task, ap);
INIT_WORK(&ap->pio_task, ata_pio_task, ap);
+ INIT_WORK(&ap->sat_task, ata_sat_task, ap);
for (i = 0; i < ATA_MAX_DEVICES; i++)
ap->device[i].devno = i;
@@ -4530,6 +4531,12 @@ static int __init ata_init(void)
if (!ata_wq)
return -ENOMEM;
+ ata_sat_wq = create_workqueue("sat");
+ if (!ata_sat_wq) {
+ destroy_workqueue(ata_wq);
+ return -ENOMEM;
+ }
+
printk(KERN_DEBUG "libata version " DRV_VERSION " loaded.\n");
return 0;
}
@@ -4537,6 +4544,7 @@ static int __init ata_init(void)
static void __exit ata_exit(void)
{
destroy_workqueue(ata_wq);
+ destroy_workqueue(ata_sat_wq);
}
module_init(ata_init);
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -36,6 +36,7 @@
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/spinlock.h>
+#include <linux/workqueue.h>
#include <scsi/scsi.h>
#include "scsi.h"
#include <scsi/scsi_host.h>
@@ -44,10 +45,26 @@
#include "libata.h"
-typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc, u8
*scsicmd);
+enum {
+ ATA_SAT_SIMULATE, /* scmd is to be simulated */
+ ATA_SAT_XLAT, /* scmd -> single qc translation */
+ ATA_SAT_SEQUENCE, /* scmd -> qc sequence translation */
+};
+
+struct ata_sat_info {
+ int mode;
+ union {
+ ata_sat_xlat_func_t xlat_func;
+ ata_sat_seq_func_t seq_func;
+ } f; /* No anonymous union yet */
+};
+
+struct workqueue_struct *ata_sat_wq;
+
static struct ata_device *
ata_scsi_find_dev(struct ata_port *ap, struct scsi_device *scsidev);
-
+static unsigned int ata_scsi_rbuf_get(struct scsi_cmnd *cmd, u8 **buf_out);
+static void ata_scsi_rbuf_put(struct scsi_cmnd *cmd, u8 *buf);
/**
* ata_std_bios_param - generic bios head/sector/cylinder calculator used
by sd.
@@ -738,7 +755,7 @@ static int ata_scsi_qc_complete(struct a
static void ata_scsi_translate(struct ata_port *ap, struct ata_device *dev,
struct scsi_cmnd *cmd,
void (*done)(struct scsi_cmnd *),
- ata_xlat_func_t xlat_func)
+ ata_sat_xlat_func_t xlat_func)
{
struct ata_queued_cmd *qc;
u8 *scsicmd = cmd->cmnd;
@@ -785,6 +802,132 @@ err_out:
DPRINTK("EXIT - badcmd\n");
}
+static int ata_scsi_seq_exec_qc(struct ata_queued_cmd *qc)
+{
+ struct ata_port *ap = qc->ap;
+ DECLARE_COMPLETION(wait);
+ unsigned long flags;
+ int rc;
+
+ qc->waiting = &wait;
+
+ spin_lock_irqsave(&ap->host_set->lock, flags);
+ rc = ata_qc_issue(qc);
+ if (rc)
+ ata_qc_free(qc);
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+ if (!rc)
+ wait_for_completion(&wait);
+ return rc;
+}
+
+static void ata_scsi_modeselect10_seq(struct ata_port *ap,
+ struct ata_device *dev,
+ struct scsi_cmnd *cmd,
+ void (*done)(struct scsi_cmnd *))
+{
+ u8 *rbuf;
+ unsigned buflen;
+ int okay = 0, wce = 0, dra = 0;
+ struct ata_queued_cmd *qc;
+
+ buflen = ata_scsi_rbuf_get(cmd, &rbuf);
+
+ if (buflen >= 21 && rbuf[8 + 0] == 0x08) {
+ wce = rbuf[8 + 2] & 0x04;
+ dra = rbuf[8 + 12] & 0x20;
+ okay = 1;
+ }
+
+ ata_scsi_rbuf_put(cmd, rbuf);
+
+ if (!okay)
+ goto err_out;
+
+ /* WCE first */
+ qc = ata_scsi_qc_new(ap, dev, cmd, done);
+ if (!qc)
+ return;
+
+ qc->tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
+ qc->tf.protocol = ATA_PROT_NODATA;
+ qc->tf.command = ATA_CMD_SET_FEATURES;
+ qc->tf.feature = wce ? 0x02 : 0x82;
+
+ if (ata_scsi_seq_exec_qc(qc))
+ goto err_out;
+
+ /* DRA now */
+ qc = ata_scsi_qc_new(ap, dev, cmd, done);
+ if (!qc)
+ return;
+
+ qc->tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
+ qc->tf.protocol = ATA_PROT_NODATA;
+ qc->tf.command = ATA_CMD_SET_FEATURES;
+ qc->tf.feature = !dra ? 0xaa : 0x55;
+
+ if (ata_scsi_seq_exec_qc(qc))
+ goto err_out;
+
+ cmd->result = SAM_STAT_GOOD;
+ done(cmd);
+ return;
+
+ err_out:
+ ata_scsi_badcmd(cmd, done, 0x20, 0x00);
+}
+
+void ata_sat_task(void *_data)
+{
+ struct ata_port *ap = _data;
+
+ ap->sat_seq_func(ap, ap->sat_dev, ap->sat_scsicmd, ap->sat_done);
+ smp_wmb();
+ ap->sat_scsicmd = NULL;
+}
+
+/**
+ * ata_scsi_sequence -
+ * @ap: ATA port to which the command is addressed
+ * @dev: ATA device to which the command is addressed
+ * @cmd: SCSI command to execute
+ * @done: SCSI command completion function
+ * @seq_func: Actor which sequences @cmd
+ *
+ * Our ->queuecommand() function has decided that the SCSI
+ * command issued should be sequenced. Note that only one
+ * concurrent sequencing is allowed per port.
+ *
+ * This function sets up an per dev sequence data and queues
+ * dev->sat_task.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ */
+
+static void ata_scsi_sequence(struct ata_port *ap, struct ata_device *dev,
+ struct scsi_cmnd *cmd,
+ void (*done)(struct scsi_cmnd *),
+ ata_sat_seq_func_t seq_func)
+{
+ if (ap->sat_scsicmd != NULL) {
+ cmd->result = (DID_OK << 16) | (QUEUE_FULL << 1);
+ done(cmd);
+ return;
+ }
+
+ ap->sat_scsicmd = cmd;
+ ap->sat_dev = dev;
+ ap->sat_seq_func = seq_func;
+ ap->sat_done = done;
+
+ queue_work(ata_sat_wq, &ap->sat_task);
+
+ return;
+}
+
/**
* ata_scsi_rbuf_get - Map response buffer.
* @cmd: SCSI command containing buffer to be mapped.
@@ -1479,19 +1622,22 @@ ata_scsi_find_dev(struct ata_port *ap, s
}
/**
- * ata_get_xlat_func - check if SCSI to ATA translation is possible
+ * ata_get_sat_info - determine how a SCSI command should be handled
* @dev: ATA device
* @cmd: SCSI command opcode to consider
*
* Look up the SCSI command given, and determine whether the
- * SCSI command is to be translated or simulated.
+ * SCSI command is to be simulated, translated or sequenced.
*
* RETURNS:
* Pointer to translation function if possible, %NULL if not.
*/
-static inline ata_xlat_func_t ata_get_xlat_func(struct ata_device *dev, u8 cmd)
+static inline struct ata_sat_info ata_get_sat_info(struct ata_device *dev,
+ u8 cmd)
{
+ struct ata_sat_info si = { .mode = ATA_SAT_SIMULATE };
+
switch (cmd) {
case READ_6:
case READ_10:
@@ -1500,21 +1646,35 @@ static inline ata_xlat_func_t ata_get_xl
case WRITE_6:
case WRITE_10:
case WRITE_16:
- return ata_scsi_rw_xlat;
+ si.mode = ATA_SAT_XLAT;
+ si.f.xlat_func = ata_scsi_rw_xlat;
+ break;
case SYNCHRONIZE_CACHE:
- if (ata_try_flush_cache(dev))
- return ata_scsi_flush_xlat;
+ if (ata_try_flush_cache(dev)) {
+ si.mode = ATA_SAT_XLAT;
+ si.f.xlat_func = ata_scsi_flush_xlat;
+ }
break;
case VERIFY:
case VERIFY_16:
- return ata_scsi_verify_xlat;
+ si.mode = ATA_SAT_XLAT;
+ si.f.xlat_func = ata_scsi_verify_xlat;
+ break;
+
case START_STOP:
- return ata_scsi_start_stop_xlat;
+ si.mode = ATA_SAT_XLAT;
+ si.f.xlat_func = ata_scsi_start_stop_xlat;
+ break;
+
+ case MODE_SELECT_10:
+ si.mode = ATA_SAT_SEQUENCE;
+ si.f.seq_func = ata_scsi_modeselect10_seq;
+ break;
}
- return NULL;
+ return si;
}
/**
@@ -1578,13 +1738,19 @@ int ata_scsi_queuecmd(struct scsi_cmnd *
}
if (dev->class == ATA_DEV_ATA) {
- ata_xlat_func_t xlat_func = ata_get_xlat_func(dev,
- cmd->cmnd[0]);
+ struct ata_sat_info si = ata_get_sat_info(dev, cmd->cmnd[0]);
- if (xlat_func)
- ata_scsi_translate(ap, dev, cmd, done, xlat_func);
- else
+ switch (si.mode) {
+ case ATA_SAT_SIMULATE:
ata_scsi_simulate(dev->id, cmd, done);
+ break;
+ case ATA_SAT_XLAT:
+ ata_scsi_translate(ap, dev, cmd, done, si.f.xlat_func);
+ break;
+ case ATA_SAT_SEQUENCE:
+ ata_scsi_sequence(ap, dev, cmd, done, si.f.seq_func);
+ break;
+ }
} else
ata_scsi_translate(ap, dev, cmd, done, atapi_xlat);
diff --git a/drivers/scsi/libata.h b/drivers/scsi/libata.h
--- a/drivers/scsi/libata.h
+++ b/drivers/scsi/libata.h
@@ -50,6 +50,10 @@ extern void swap_buf_le16(u16 *buf, unsi
/* libata-scsi.c */
+extern struct workqueue_struct *ata_sat_wq;
+
+extern void ata_sat_task(void *_data);
+
extern void ata_to_sense_error(struct ata_queued_cmd *qc, u8 drv_stat);
extern int ata_scsi_error(struct Scsi_Host *host);
extern unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,
diff --git a/include/linux/libata.h b/include/linux/libata.h
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -172,10 +172,16 @@ enum pio_task_states {
struct scsi_device;
struct ata_port_operations;
struct ata_port;
+struct ata_device;
struct ata_queued_cmd;
/* typedefs */
typedef int (*ata_qc_cb_t) (struct ata_queued_cmd *qc, u8 drv_stat);
+typedef unsigned int (*ata_sat_xlat_func_t)(struct ata_queued_cmd *qc,
+ u8 *scsicmd);
+typedef void (*ata_sat_seq_func_t)(struct ata_port *ap,struct ata_device *dev,
+ struct scsi_cmnd *cmd,
+ void (*done)(struct scsi_cmnd *));
struct ata_ioports {
unsigned long cmd_addr;
@@ -323,6 +329,12 @@ struct ata_port {
unsigned int pio_task_state;
unsigned long pio_task_timeout;
+ struct work_struct sat_task;
+ struct scsi_cmnd *sat_scsicmd;
+ struct ata_device *sat_dev;
+ ata_sat_seq_func_t sat_seq_func;
+ void (*sat_done)(struct scsi_cmnd *);
+
void *private_data;
};
-
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