path: root/drivers/usb/storage/uas.c

// SPDX-License-Identifier: GPL-2.0
/*
 * USB Attached SCSI
 * Note that this is not the same as the USB Mass Storage driver
 *
 * Copyright Hans de Goede <hdegoede@redhat.com> for Red Hat, Inc. 2013 - 2016
 * Copyright Matthew Wilcox for Intel Corp, 2010
 * Copyright Sarah Sharp for Intel Corp, 2010
 */

#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb_usual.h>
#include <linux/usb/hcd.h>
#include <linux/usb/storage.h>
#include <linux/usb/uas.h>

#include <scsi/scsi.h>
#include <scsi/scsi_eh.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>

#include "uas-detect.h"
#include "scsiglue.h"

#define MAX_CMNDS 256

struct uas_dev_info {
	struct usb_interface *intf;
	struct usb_device *udev;
	struct usb_anchor cmd_urbs;
	struct usb_anchor sense_urbs;
	struct usb_anchor data_urbs;
	unsigned long flags;
	int qdepth, resetting;
	unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
	unsigned use_streams:1;
	unsigned shutdown:1;
	struct scsi_cmnd *cmnd[MAX_CMNDS];
	spinlock_t lock;
	struct work_struct work;
	struct work_struct scan_work;      /* for async scanning */
};

enum {
	SUBMIT_STATUS_URB	= BIT(1),
	ALLOC_DATA_IN_URB	= BIT(2),
	SUBMIT_DATA_IN_URB	= BIT(3),
	ALLOC_DATA_OUT_URB	= BIT(4),
	SUBMIT_DATA_OUT_URB	= BIT(5),
	ALLOC_CMD_URB		= BIT(6),
	SUBMIT_CMD_URB		= BIT(7),
	COMMAND_INFLIGHT        = BIT(8),
	DATA_IN_URB_INFLIGHT    = BIT(9),
	DATA_OUT_URB_INFLIGHT   = BIT(10),
	COMMAND_ABORTED         = BIT(11),
	IS_IN_WORK_LIST         = BIT(12),
};

/* Overrides scsi_pointer */
struct uas_cmd_info {
	unsigned int state;
	unsigned int uas_tag;
	struct urb *cmd_urb;
	struct urb *data_in_urb;
	struct urb *data_out_urb;
};

/* I hate forward declarations, but I actually have a loop */
static int uas_submit_urbs(struct scsi_cmnd *cmnd,
				struct uas_dev_info *devinfo);
static void uas_do_work(struct work_struct *work);
static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller);
static void uas_free_streams(struct uas_dev_info *devinfo);
static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *prefix,
				int status);

/*
 * This driver needs its own workqueue, as we need to control memory allocation.
 *
 * In the course of error handling and power management uas_wait_for_pending_cmnds()
 * needs to flush pending work items. In these contexts we cannot allocate memory
 * by doing block IO as we would deadlock. For the same reason we cannot wait
 * for anything allocating memory not heeding these constraints.
 *
 * So we have to control all work items that can be on the workqueue we flush.
 * Hence we cannot share a queue and need our own.
 */
static struct workqueue_struct *workqueue;

static void uas_do_work(struct work_struct *work)
{
	struct uas_dev_info *devinfo =
		container_of(work, struct uas_dev_info, work);
	struct uas_cmd_info *cmdinfo;
	struct scsi_cmnd *cmnd;
	unsigned long flags;
	int i, err;

	spin_lock_irqsave(&devinfo->lock, flags);</