Am Dienstag, 28. September 2010, 12:14:56 schrieb Matthew Wilcox:
> From: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
>
> USB Attached SCSI is a new protocol specified jointly by the SCSI T10
> committee and the USB Implementors Forum.
>
> Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> ---
> MAINTAINERS | 8 +
> drivers/usb/storage/Kconfig | 13 +
> drivers/usb/storage/Makefile | 1 +
> drivers/usb/storage/uas.c | 751 ++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 773 insertions(+), 0 deletions(-)
> create mode 100644 drivers/usb/storage/uas.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 668682d..30a5c22 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5900,6 +5900,14 @@ S: Maintained
> F: Documentation/usb/acm.txt
> F: drivers/usb/class/cdc-acm.*
>
> +USB ATTACHED SCSI
> +M: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> +M: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
> +L: linux-usb@xxxxxxxxxxxxxxx
> +L: linux-scsi@xxxxxxxxxxxxxxx
> +S: Supported
> +F: drivers/usb/storage/uas.c
> +
> USB BLOCK DRIVER (UB ub)
> M: Pete Zaitcev <zaitcev@xxxxxxxxxx>
> L: linux-usb@xxxxxxxxxxxxxxx
> diff --git a/drivers/usb/storage/Kconfig b/drivers/usb/storage/Kconfig
> index 8a372ba..f2767cf 100644
> --- a/drivers/usb/storage/Kconfig
> +++ b/drivers/usb/storage/Kconfig
> @@ -172,6 +172,19 @@ config USB_STORAGE_CYPRESS_ATACB
>
> If this driver is compiled as a module, it will be named ums-cypress.
>
> +config USB_UAS
> + tristate "USB Attached SCSI"
> + depends on USB && SCSI
> + help
> + The USB Attached SCSI protocol is supported by some USB
> + storage devices. It permits higher performance by supporting
> + multiple outstanding commands.
> +
> + If you don't know whether you have a UAS device, it is safe to
> + say 'Y' or 'M' here and the kernel will use the right driver.
> +
> + If you compile this driver as a module, it will be named uas.
> +
> config USB_LIBUSUAL
> bool "The shared table of common (or usual) storage devices"
> depends on USB
> diff --git a/drivers/usb/storage/Makefile b/drivers/usb/storage/Makefile
> index ef7e5a8..0332aa5 100644
> --- a/drivers/usb/storage/Makefile
> +++ b/drivers/usb/storage/Makefile
> @@ -7,6 +7,7 @@
>
> EXTRA_CFLAGS := -Idrivers/scsi
>
> +obj-$(CONFIG_USB_UAS) += uas.o
> obj-$(CONFIG_USB_STORAGE) += usb-storage.o
>
> usb-storage-obj-$(CONFIG_USB_STORAGE_DEBUG) += debug.o
> diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
> new file mode 100644
> index 0000000..7fd049b
> --- /dev/null
> +++ b/drivers/usb/storage/uas.c
> @@ -0,0 +1,751 @@
> +/*
> + * USB Attached SCSI
> + * Note that this is not the same as the USB Mass Storage driver
> + *
> + * Copyright Matthew Wilcox for Intel Corp, 2010
> + * Copyright Sarah Sharp for Intel Corp, 2010
> + *
> + * Distributed under the terms of the GNU GPL, version two.
> + */
> +
> +#include <linux/blkdev.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/usb.h>
> +#include <linux/usb/storage.h>
> +
> +#include <scsi/scsi.h>
> +#include <scsi/scsi_dbg.h>
> +#include <scsi/scsi_cmnd.h>
> +#include <scsi/scsi_device.h>
> +#include <scsi/scsi_host.h>
> +#include <scsi/scsi_tcq.h>
> +
> +/* Common header for all IUs */
> +struct iu {
> + __u8 iu_id;
> + __u8 rsvd1;
> + __be16 tag;
> +};
> +
> +enum {
> + IU_ID_COMMAND = 0x01,
> + IU_ID_STATUS = 0x03,
> + IU_ID_RESPONSE = 0x04,
> + IU_ID_TASK_MGMT = 0x05,
> + IU_ID_READ_READY = 0x06,
> + IU_ID_WRITE_READY = 0x07,
> +};
> +
> +struct command_iu {
> + __u8 iu_id;
> + __u8 rsvd1;
> + __be16 tag;
> + __u8 prio_attr;
> + __u8 rsvd5;
> + __u8 len;
> + __u8 rsvd7;
> + struct scsi_lun lun;
> + __u8 cdb[16]; /* XXX: Overflow-checking tools may misunderstand */
> +};
> +
> +struct sense_iu {
> + __u8 iu_id;
> + __u8 rsvd1;
> + __be16 tag;
> + __be16 status_qual;
> + __u8 status;
> + __u8 service_response;
> + __u8 rsvd8[6];
> + __be16 len;
> + __u8 sense[SCSI_SENSE_BUFFERSIZE];
> +};
> +
> +/*
> + * The r00-r01c specs define this version of the SENSE IU data structure.
> + * It's still in use by several different firmware releases.
> + */
> +struct sense_iu_old {
> + __u8 iu_id;
> + __u8 rsvd1;
> + __be16 tag;
> + __be16 len;
> + __u8 status;
> + __u8 service_response;
> + __u8 sense[SCSI_SENSE_BUFFERSIZE];
> +};
> +
> +enum {
> + CMD_PIPE_ID = 1,
> + STATUS_PIPE_ID = 2,
> + DATA_IN_PIPE_ID = 3,
> + DATA_OUT_PIPE_ID = 4,
> +
> + UAS_SIMPLE_TAG = 0,
> + UAS_HEAD_TAG = 1,
> + UAS_ORDERED_TAG = 2,
> + UAS_ACA = 4,
> +};
> +
> +struct uas_dev_info {
> + struct usb_interface *intf;
> + struct usb_device *udev;
> + int qdepth;
> + unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
> + unsigned use_streams:1;
> + unsigned uas_sense_old:1;
> +};
> +
> +enum {
> + ALLOC_SENSE_URB = (1 << 0),
> + SUBMIT_SENSE_URB = (1 << 1),
> + ALLOC_DATA_IN_URB = (1 << 2),
> + SUBMIT_DATA_IN_URB = (1 << 3),
> + ALLOC_DATA_OUT_URB = (1 << 4),
> + SUBMIT_DATA_OUT_URB = (1 << 5),
> + ALLOC_CMD_URB = (1 << 6),
> + SUBMIT_CMD_URB = (1 << 7),
> +};
> +
> +/* Overrides scsi_pointer */
> +struct uas_cmd_info {
> + unsigned int state;
> + unsigned int stream;
> + struct urb *cmd_urb;
> + struct urb *sense_urb;
> + struct urb *data_in_urb;
> + struct urb *data_out_urb;
> + struct list_head list;
> +};
> +
> +/* I hate forward declarations, but I actually have a loop */
> +static int uas_submit_urbs(struct scsi_cmnd *cmnd,
> + struct uas_dev_info *devinfo, gfp_t gfp);
> +
> +static DEFINE_SPINLOCK(uas_work_lock);
> +static LIST_HEAD(uas_work_list);
> +
> +static void uas_do_work(struct work_struct *work)
> +{
> + struct uas_cmd_info *cmdinfo;
> + struct list_head list;
> +
> + spin_lock_irq(&uas_work_lock);
> + list_replace_init(&uas_work_list, &list);
> + spin_unlock_irq(&uas_work_lock);
> +
> + list_for_each_entry(cmdinfo, &list, list) {
> + struct scsi_pointer *scp = (void *)cmdinfo;
> + struct scsi_cmnd *cmnd = container_of(scp,
> + struct scsi_cmnd, SCp);
> + uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_KERNEL);
Deadlocky, use GFP_NOIO
> + }
> +}
> +
> +static DECLARE_WORK(uas_work, uas_do_work);
> +
> +static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
> +{
> + struct sense_iu *sense_iu = urb->transfer_buffer;
> + struct scsi_device *sdev = cmnd->device;
> +
> + if (urb->actual_length > 16) {
> + unsigned len = be16_to_cpup(&sense_iu->len);
> + if (len + 16 != urb->actual_length) {
> + int newlen = min(len + 16, urb->actual_length) - 16;
> + if (newlen < 0)
> + newlen = 0;
> + sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
> + "disagrees with IU sense data length %d, "
> + "using %d bytes of sense data\n", __func__,
> + urb->actual_length, len, newlen);
> + len = newlen;
> + }
> + memcpy(cmnd->sense_buffer, sense_iu->sense, len);
> + }
> +
> + cmnd->result = sense_iu->status;
> + if (sdev->current_cmnd)
> + sdev->current_cmnd = NULL;
the condition is absolutely senseless
> + cmnd->scsi_done(cmnd);
> + usb_free_urb(urb);
> +}
> +
> +static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
> +{
> + struct sense_iu_old *sense_iu = urb->transfer_buffer;
> + struct scsi_device *sdev = cmnd->device;
> +
> + if (urb->actual_length > 8) {
> + unsigned len = be16_to_cpup(&sense_iu->len) - 2;
> + if (len + 8 != urb->actual_length) {
> + int newlen = min(len + 8, urb->actual_length) - 8;
> + if (newlen < 0)
> + newlen = 0;
> + sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
> + "disagrees with IU sense data length %d, "
> + "using %d bytes of sense data\n", __func__,
> + urb->actual_length, len, newlen);
> + len = newlen;
> + }
> + memcpy(cmnd->sense_buffer, sense_iu->sense, len);
> + }
> +
> + cmnd->result = sense_iu->status;
> + if (sdev->current_cmnd)
> + sdev->current_cmnd = NULL;
> + cmnd->scsi_done(cmnd);
> + usb_free_urb(urb);
> +}
> +
> +static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
> + unsigned direction)
> +{
> + struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
> + int err;
> +
> + cmdinfo->state = direction | SUBMIT_SENSE_URB;
> + err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
> + if (err) {
> + spin_lock(&uas_work_lock);
> + list_add_tail(&cmdinfo->list, &uas_work_list);
> + spin_unlock(&uas_work_lock);
> + schedule_work(&uas_work);
> + }
> +}
> +
> +static void uas_stat_cmplt(struct urb *urb)
> +{
> + struct iu *iu = urb->transfer_buffer;
> + struct scsi_device *sdev = urb->context;
> + struct uas_dev_info *devinfo = sdev->hostdata;
> + struct scsi_cmnd *cmnd;
> + u16 tag;
> +
> + if (urb->status) {
> + dev_err(&urb->dev->dev, "URB BAD STATUS %d\n", urb->status);
> + usb_free_urb(urb);
> + return;
> + }
> +
> + tag = be16_to_cpup(&iu->tag) - 1;
> + if (sdev->current_cmnd)
> + cmnd = sdev->current_cmnd;
> + else
> + cmnd = scsi_find_tag(sdev, tag);
> + if (!cmnd)
> + return;
Where is the URB freed?
> + switch (iu->iu_id) {
> + case IU_ID_STATUS:
> + if (urb->actual_length < 16)
> + devinfo->uas_sense_old = 1;
> + if (devinfo->uas_sense_old)
> + uas_sense_old(urb, cmnd);
> + else
> + uas_sense(urb, cmnd);
> + break;
> + case IU_ID_READ_READY:
> + uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
> + break;
> + case IU_ID_WRITE_READY:
> + uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
> + break;
> + default:
> + scmd_printk(KERN_ERR, cmnd,
> + "Bogus IU (%d) received on status pipe\n", iu->iu_id);
> + }
> +}
> +
> +static int uas_pre_reset(struct usb_interface *intf)
> +{
> +/* XXX: Need to return 1 if it's not our device in error handling */
> + return 0;
> +}
You should probably make sure that no further commands are
queued from this point on.
> +static int uas_post_reset(struct usb_interface *intf)
> +{
> +/* XXX: Need to return 1 if it's not our device in error handling */
> + return 0;
> +}
> +
> +static void uas_disconnect(struct usb_interface *intf)
> +{
> + struct usb_device *udev = interface_to_usbdev(intf);
> + struct usb_host_endpoint *eps[3];
> + struct Scsi_Host *shost = usb_get_intfdata(intf);
> + struct uas_dev_info *devinfo = (void *)shost->hostdata[0];
> +
> + scsi_remove_host(shost);
> +
> + eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
> + eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
> + eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
> + usb_free_streams(intf, eps, 3, GFP_KERNEL);
This implies that this can fail due to a lack of memory.
Then what?
Regards
Oliver
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