Hi,
Currently, it is not possible to know on what particular port an ata
device is located with sysfs. the current scheme creates an host<x>
directory directly under the sata host device node like this (with a
sata_mv driver, having two sata ports):
/sys/platform/sata_mv.0/host<x>
/sys/platform/sata_mv.0/host<y>
If the system probes successfully other scsi devices before probing
the sata bus, we have no guarantees that the same numbers will be used
all the time, and if we rmmod/modprobe sata_mv the host numbers are
not persistent accross module insertion.
The inlined patch fixes this by adding a port<x> device that is
parented to the sata controller device and uses this device as a base
to create the scsi hosts for the devices behind a given sata port. <x>
is set to be the value of the port_no field in struct ata_port.
the naming then looks like this (assuming two sata ports behind a
sata_mv driver):
/sys/platform/sata_mv.0/port0/host<x>
/sys/platform/sata_mv.0/port1/host<y>
My patch adds a struct device inside struct ata_port for the sole
purpose of having this port0,port1,... directory under sata_mv.
This patch also moves the assignation of port_no to ata_port_alloc to
ease the initialisation of the device structure embedded in sata_port.
this most likely messes up the ata_sas_port_alloc code which always
sets port_no to 0 and will make device_add complain loudly in dmesg if
this function is called more than once. Unfortunately I do not have
any SAS devices at hand to fix this.
I do not know yet how this would behave with sata devices behind a
SATA port multiplier but I would guess that no new scsi host would be
created in this case and that the other fields of target<host>:x:y:z
would be used by the scsi subsystem.
This is not a very polished patch and it is aimed to know whether the
approach used is correct and I would like to have your advices
regarding this.
Regards,
Signed-off-by: Nicolas Schichan <nschichan@xxxxxxxxxx>
--
Nicolas Schichan
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 91fed3c..179abad 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5660,6 +5660,10 @@ int sata_link_init_spd(struct ata_link *link)
return 0;
}
+static void ata_port_dev_release(struct device *dev)
+{
+}
+
/**
* ata_port_alloc - allocate and initialize basic ATA port resources
* @host: ATA host this allocated port belongs to
@@ -5672,7 +5676,7 @@ int sata_link_init_spd(struct ata_link *link)
* LOCKING:
* Inherited from calling layer (may sleep).
*/
-struct ata_port *ata_port_alloc(struct ata_host *host)
+struct ata_port *ata_port_alloc(struct ata_host *host, int port_no)
{
struct ata_port *ap;
@@ -5690,6 +5694,20 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
ap->host = host;
ap->dev = host->dev;
ap->last_ctl = 0xFF;
+ ap->port_no = port_no;
+
+ /*
+ * register device used to add the scsi host behind this
+ * port. make it a parent of the struct device of the host.
+ */
+ ap->ata_port_device.release = ata_port_dev_release;
+ dev_set_name(&ap->ata_port_device, "port%i", ap->port_no);
+ ap->ata_port_device.parent = ap->dev;
+ if (device_register(&ap->ata_port_device) < 0) {
+ kfree(ap);
+ return NULL;
+ }
+
#if defined(ATA_VERBOSE_DEBUG)
/* turn on all debugging levels */
@@ -5739,6 +5757,9 @@ static void ata_host_release(struct device *gendev, void *res)
if (ap->scsi_host)
scsi_host_put(ap->scsi_host);
+
+ device_unregister(&ap->ata_port_device);
+
kfree(ap->pmp_link);
kfree(ap->slave_link);
kfree(ap);
@@ -5797,11 +5818,10 @@ struct ata_host *ata_host_alloc(struct device *dev, int max_ports)
for (i = 0; i < max_ports; i++) {
struct ata_port *ap;
- ap = ata_port_alloc(host);
+ ap = ata_port_alloc(host, i);
if (!ap)
goto err_out;
- ap->port_no = i;
host->ports[i] = ap;
}
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index b4ee28d..1cbda75 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3210,7 +3210,7 @@ int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
*/
shost->max_host_blocked = 1;
- rc = scsi_add_host(ap->scsi_host, ap->host->dev);
+ rc = scsi_add_host(ap->scsi_host, &ap->ata_port_device);
if (rc)
goto err_add;
}
@@ -3593,11 +3593,10 @@ struct ata_port *ata_sas_port_alloc(struct ata_host *host,
{
struct ata_port *ap;
- ap = ata_port_alloc(host);
+ ap = ata_port_alloc(host, 0);
if (!ap)
return NULL;
- ap->port_no = 0;
ap->lock = shost->host_lock;
ap->pio_mask = port_info->pio_mask;
ap->mwdma_mask = port_info->mwdma_mask;
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 823e630..cd44e9e 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -112,7 +112,7 @@ extern void ata_link_init(struct ata_port *ap, struct ata_link *link, int pmp);
extern int sata_link_init_spd(struct ata_link *link);
extern int ata_task_ioctl(struct scsi_device *scsidev, void __user *arg);
extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
-extern struct ata_port *ata_port_alloc(struct ata_host *host);
+extern struct ata_port *ata_port_alloc(struct ata_host *host, int port_no);
extern void ata_dev_enable_pm(struct ata_device *dev, enum link_pm policy);
extern void ata_lpm_schedule(struct ata_port *ap, enum link_pm);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index b0f6d97..64d94d9 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -749,6 +749,9 @@ struct ata_port {
struct ata_host *host;
struct device *dev;
+ /* used as base to create scsi host behind the port.*/
+ struct device ata_port_device;
+
void *port_task_data;
struct delayed_work port_task;
struct delayed_work hotplug_task;
--
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