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SubjectRe: [RFC] UASP on target (was: [RFC/PATCH v4 1/3] uas: MS UAS Gadget driver - Infrastructure)
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On Mon, 2011-12-05 at 09:23 +0100, Sebastian Andrzej Siewior wrote:
> * Sebastian Andrzej Siewior | 2011-12-05 09:20:47 [+0100]:
>
> >* Shimrit Malichi | 2011-12-04 21:53:09 [+0200]:
> >
> >>This patch implements the infrastructure for the UAS gadget driver.
> >>The UAS gadget driver registers as a second configuration of the MS
> >>gadet driver.
> >hch said to use target framework and you haven't done so. This is what I
> >have so far. It is not yet complete. What I need to do is:
> >- wire up command processing (currently here)
> >- wire up data processing
> >- check it works => post v1
> >- wire up command tagging => v2
> >- remove hard codings and fix whatever people complained about.
>

Hi Sebastian,

So this looks like a reasonable first step to get a control plane up
for /sys/kernel/config/target/uasp/. I have not at the USB parts beyond
the initial patch so I can't really comment there, but thanks for using
tcm_mod_builder.py to generate your initial skeleton.

Just a minor few comments below on the target-related pieces below, and
a few comments to keep in mind for he main I/O path with struct
uasp_cmd->se_cmd descriptor usage.

> diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
> index e66fcc7..64d3204 100644
> --- a/drivers/target/Kconfig
> +++ b/drivers/target/Kconfig
> @@ -50,3 +50,4 @@ source "drivers/target/tcm_qla2xxx/Kconfig"
> source "drivers/target/tcm_vhost/Kconfig"
>
> endif
> +source "drivers/target/uasp/Kconfig"
> diff --git a/drivers/target/Makefile b/drivers/target/Makefile
> index 1945dba..b1135d5 100644
> --- a/drivers/target/Makefile
> +++ b/drivers/target/Makefile
> @@ -28,3 +28,4 @@ obj-$(CONFIG_TCM_FC) += tcm_fc/
> obj-$(CONFIG_ISCSI_TARGET) += iscsi/
> obj-$(CONFIG_TCM_QLA2XXX) += tcm_qla2xxx/
> obj-$(CONFIG_TCM_VHOST) += tcm_vhost/
> +obj-$(CONFIG_TARGET_UASP) += uasp/
> diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
> index f7cb64f..127496a 100644
> --- a/drivers/target/target_core_configfs.c
> +++ b/drivers/target/target_core_configfs.c
> @@ -162,6 +162,13 @@ static struct config_group *target_core_register_fabric(
> " tcm_loop.ko: %d\n", ret);
> return ERR_PTR(-EINVAL);
> }
> + } else if (!strncmp(name, "uasp", 4)) {
> + ret = request_module("tcm_uasp");
> + if (ret < 0) {
> + pr_err("request_module() failed for"
> + " tcm_loop.ko: %d\n", ret);
> + return ERR_PTR(-EINVAL);
> + }
> }
>
> tf = target_core_get_fabric(name);

So making the request_module() calls was an original feature of v3.x
target core code, but this is not strictly required for normal usage
after loading the module, or with rtslib /var/target/spec/uasp.spec
usage.

As we are trying to avoid extra request_module() usage in target-core,
please go ahead and drop this part for now..

> diff --git a/drivers/target/uasp/Kconfig b/drivers/target/uasp/Kconfig
> new file mode 100644
> index 0000000..0d48a58
> --- /dev/null
> +++ b/drivers/target/uasp/Kconfig
> @@ -0,0 +1,6 @@
> +config TARGET_UASP
> + tristate "UASP fabric module"
> + depends on TARGET_CORE && CONFIGFS_FS
> + depends on USB_GADGET
> + ---help---
> + Say Y here to enable the UASP fabric module
> diff --git a/drivers/target/uasp/Makefile b/drivers/target/uasp/Makefile
> new file mode 100644
> index 0000000..25883ab
> --- /dev/null
> +++ b/drivers/target/uasp/Makefile
> @@ -0,0 +1,5 @@
> +CFLAGS_gadget.o := -I$(srctree)/drivers/usb/gadget
> +tcm_uasp-objs := uasp_fabric.o \
> + gadget.o \
> + uasp_configfs.o
> +obj-$(CONFIG_TARGET_UASP) += tcm_uasp.o
> diff --git a/drivers/target/uasp/gadget.c b/drivers/target/uasp/gadget.c
> new file mode 100644

<SNIP>

> diff --git a/drivers/target/uasp/uasp_configfs.c b/drivers/target/uasp/uasp_configfs.c
> new file mode 100644
> index 0000000..7f6b280
> --- /dev/null
> +++ b/drivers/target/uasp/uasp_configfs.c
> @@ -0,0 +1,333 @@
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/version.h>
> +#include <generated/utsrelease.h>
> +#include <linux/utsname.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/kthread.h>
> +#include <linux/types.h>
> +#include <linux/string.h>
> +#include <linux/configfs.h>
> +#include <linux/ctype.h>
> +#include <asm/unaligned.h>
> +
> +#include <target/target_core_base.h>
> +#include <target/target_core_fabric.h>
> +#include <target/target_core_fabric_configfs.h>
> +#include <target/target_core_configfs.h>
> +#include <target/configfs_macros.h>
> +
> +#include "uasp_base.h"
> +#include "uasp_fabric.h"
> +#include "gadget_ops.h"
> +
> +/* Local pointer to allocated TCM configfs fabric module */
> +struct target_fabric_configfs *uasp_fabric_configfs;
> +
> +static const char *uasp_check_wwn(const char *name)
> +{
> + const char *n;
> + unsigned int len;
> +
> + n = strstr(name, "naa.");
> + if (!n)
> + return NULL;
> + n += 4;
> + len = strlen(n);
> + if (len == 0 || len > UASP_NAMELEN - 1)
> + return NULL;
> + return n;
> +}
> +

Note this is currently using naa. prefixed targetnames for UASP
endpoints, as loopback does with SAS proto_id port emulation..

> +int uasp_register_configfs(void)
> +{
> + struct target_fabric_configfs *fabric;
> + int ret;
> +
> + printk(KERN_INFO "UASP fabric module %s on %s/%s"
> + " on "UTS_RELEASE"\n",UASP_VERSION, utsname()->sysname,
> + utsname()->machine);
> + /*
> + * Register the top level struct config_item_type with TCM core
> + */
> + fabric = target_fabric_configfs_init(THIS_MODULE, "uasp");
> + if (!(fabric)) {
> + printk(KERN_ERR "target_fabric_configfs_init() failed\n");
> + return -ENOMEM;
> + }

This should be checking using IS_ERR() with fabric, which is a current
bug in tcm_mod_builder.py

> + /*
> + * Setup fabric->tf_ops from our local uasp_ops
> + */
> + fabric->tf_ops = uasp_ops;
> + /*
> + * Setup default attribute lists for various fabric->tf_cit_tmpl
> + */
> + TF_CIT_TMPL(fabric)->tfc_wwn_cit.ct_attrs = uasp_wwn_attrs;
> + TF_CIT_TMPL(fabric)->tfc_tpg_base_cit.ct_attrs = uasp_base_attrs;
> + TF_CIT_TMPL(fabric)->tfc_tpg_attrib_cit.ct_attrs = NULL;
> + TF_CIT_TMPL(fabric)->tfc_tpg_param_cit.ct_attrs = NULL;
> + TF_CIT_TMPL(fabric)->tfc_tpg_np_base_cit.ct_attrs = NULL;
> + TF_CIT_TMPL(fabric)->tfc_tpg_nacl_base_cit.ct_attrs = NULL;
> + TF_CIT_TMPL(fabric)->tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;
> + TF_CIT_TMPL(fabric)->tfc_tpg_nacl_auth_cit.ct_attrs = NULL;
> + TF_CIT_TMPL(fabric)->tfc_tpg_nacl_param_cit.ct_attrs = NULL;
> + /*
> + * Register the fabric for use within TCM
> + */
> + ret = target_fabric_configfs_register(fabric);
> + if (ret < 0) {
> + printk(KERN_ERR "target_fabric_configfs_register() failed"
> + " for UASP\n");
> + return ret;
> + }
> + /*
> + * Setup our local pointer to *fabric
> + */
> + uasp_fabric_configfs = fabric;
> + printk(KERN_INFO "UASP[0] - Set fabric -> uasp_fabric_configfs\n");
> + return 0;
> +};
> +
> +void uasp_deregister_configfs(void)
> +{
> + if (!(uasp_fabric_configfs))
> + return;
> +
> + target_fabric_configfs_deregister(uasp_fabric_configfs);
> + uasp_fabric_configfs = NULL;
> + printk(KERN_INFO "UASP[0] - Cleared uasp_fabric_configfs\n");
> +};

> diff --git a/drivers/target/uasp/uasp_fabric.c b/drivers/target/uasp/uasp_fabric.c
> new file mode 100644
> index 0000000..304c934
> --- /dev/null
> +++ b/drivers/target/uasp/uasp_fabric.c
> @@ -0,0 +1,287 @@
> +#include <linux/slab.h>
> +#include <linux/kthread.h>
> +#include <linux/types.h>
> +#include <linux/list.h>
> +#include <linux/types.h>
> +#include <linux/string.h>
> +#include <linux/ctype.h>
> +#include <asm/unaligned.h>
> +#include <scsi/scsi.h>
> +#include <scsi/scsi_host.h>
> +#include <scsi/scsi_device.h>
> +#include <scsi/scsi_cmnd.h>
> +#include <scsi/libfc.h>
> +
> +#include <target/target_core_base.h>
> +#include <target/target_core_fabric.h>
> +#include <target/target_core_configfs.h>
> +
> +#include "uasp_base.h"
> +#include "uasp_fabric.h"
> +
> +int uasp_check_true(struct se_portal_group *se_tpg)
> +{
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return 1;
> +}
> +
> +int uasp_check_false(struct se_portal_group *se_tpg)
> +{
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return 0;
> +}
> +
> +char *uasp_get_fabric_name(void)
> +{
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return "uasp";
> +}
> +
> +u8 uasp_get_fabric_proto_ident(struct se_portal_group *se_tpg)
> +{
> + struct uasp_tpg *tpg = container_of(se_tpg,
> + struct uasp_tpg, se_tpg);
> + struct uasp_tport *tport = tpg->tport;
> + u8 proto_id;
> +
> + switch (tport->tport_proto_id) {
> + case SCSI_PROTOCOL_SAS:
> + default:
> + proto_id = sas_get_fabric_proto_ident(se_tpg);
> + break;
> + }
> +
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return proto_id;
> +}
> +
> +char *uasp_get_fabric_wwn(struct se_portal_group *se_tpg)
> +{
> + struct uasp_tpg *tpg = container_of(se_tpg,
> + struct uasp_tpg, se_tpg);
> + struct uasp_tport *tport = tpg->tport;
> +
> + printk(KERN_ERR "%s(%d) '%s'\n", __func__, __LINE__, tport->tport_name);
> + return &tport->tport_name[0];
> +}
> +
> +u16 uasp_get_tag(struct se_portal_group *se_tpg)
> +{
> + struct uasp_tpg *tpg = container_of(se_tpg,
> + struct uasp_tpg, se_tpg);
> + printk(KERN_ERR "%s(%d) %d\n", __func__, __LINE__, tpg->tport_tpgt);
> + return tpg->tport_tpgt;
> +}
> +
> +u32 uasp_get_default_depth(struct se_portal_group *se_tpg)
> +{
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return 1;
> +}
> +
> +u32 uasp_get_pr_transport_id(
> + struct se_portal_group *se_tpg,
> + struct se_node_acl *se_nacl,
> + struct t10_pr_registration *pr_reg,
> + int *format_code,
> + unsigned char *buf)
> +{
> + struct uasp_tpg *tpg = container_of(se_tpg,
> + struct uasp_tpg, se_tpg);
> + struct uasp_tport *tport = tpg->tport;
> + int ret = 0;
> +
> + switch (tport->tport_proto_id) {
> + case SCSI_PROTOCOL_SAS:
> + default:
> + ret = sas_get_pr_transport_id(se_tpg, se_nacl, pr_reg,
> + format_code, buf);
> + break;
> + }
> +
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return ret;
> +}
> +
> +u32 uasp_get_pr_transport_id_len(
> + struct se_portal_group *se_tpg,
> + struct se_node_acl *se_nacl,
> + struct t10_pr_registration *pr_reg,
> + int *format_code)
> +{
> + struct uasp_tpg *tpg = container_of(se_tpg,
> + struct uasp_tpg, se_tpg);
> + struct uasp_tport *tport = tpg->tport;
> + int ret = 0;
> +
> + switch (tport->tport_proto_id) {
> + case SCSI_PROTOCOL_SAS:
> + default:
> + ret = sas_get_pr_transport_id_len(se_tpg, se_nacl, pr_reg,
> + format_code);
> + break;
> + }
> +
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return ret;
> +}
> +
> +char *uasp_parse_pr_out_transport_id(
> + struct se_portal_group *se_tpg,
> + const char *buf,
> + u32 *out_tid_len,
> + char **port_nexus_ptr)
> +{
> + struct uasp_tpg *tpg = container_of(se_tpg,
> + struct uasp_tpg, se_tpg);
> + struct uasp_tport *tport = tpg->tport;
> + char *tid = NULL;
> +
> + switch (tport->tport_proto_id) {
> + case SCSI_PROTOCOL_SAS:
> + default:
> + tid = sas_parse_pr_out_transport_id(se_tpg, buf, out_tid_len,
> + port_nexus_ptr);
> + }
> +
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return tid;
> +}
> +
> +struct se_node_acl *uasp_alloc_fabric_acl(struct se_portal_group *se_tpg)
> +{
> + struct uasp_nacl *nacl;
> +
> + nacl = kzalloc(sizeof(struct uasp_nacl), GFP_KERNEL);
> + if (!(nacl)) {
> + printk(KERN_ERR "Unable to alocate struct uasp_nacl\n");
> + return NULL;
> + }
> +
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + return &nacl->se_node_acl;
> +}
> +
> +void uasp_release_fabric_acl(
> + struct se_portal_group *se_tpg,
> + struct se_node_acl *se_nacl)
> +{
> + struct uasp_nacl *nacl = container_of(se_nacl,
> + struct uasp_nacl, se_node_acl);
> + printk(KERN_ERR "%s(%d)\n", __func__, __LINE__);
> + kfree(nacl);
> +}
> +

<SNIP>

So for the primary incoming I/O path, you'll want to be using the new
target_submit_cmd() call that we've been working on in
lio-core.git/qla_tgt-3.3 recently, as this will simplify incoming I/O +
exception handling for struct uasp_cmd from processing context usage.

Also, do you expect this new driver to pass pre-populated scatterlists,
or to leave se_cmd->t_data_sg allocation up to target-core..? Depending
on the expected usage this will look slightly different from the current
usage in tcm_loop/tcm_vhost that both pass pre-populated scatterlists
from Linux/SCSI.

Aside from that, let me know if you have questions while filling in the
write_pending and response (queue_data_in + queue_status) fabric
callbacks.

Thanks!

--nab



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