cxlflash: Superpipe support

Add superpipe supporting infrastructure to device driver for the IBM CXL
Flash adapter. This patch allows userspace applications to take advantage
of the accelerated I/O features that this adapter provides and bypass the
traditional filesystem stack.
Signed-off-by: NMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: NManoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: NMichael Neuling <mikey@neuling.org>
Reviewed-by: NWen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: NBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Documentation/ioctl/ioctl-number.txt

@@ -314,6 +314,7 @@ Code  Seq#(hex)	Include File		Comments
 0xB3	00	linux/mmc/ioctl.h
 0xC0	00-0F	linux/usb/iowarrior.h
 0xCA	00-0F	uapi/misc/cxl.h
+0xCA	80-8F	uapi/scsi/cxlflash_ioctl.h
 0xCB	00-1F	CBM serial IEC bus	in development:
 					<mailto:michael.klein@puffin.lb.shuttle.de>
 0xCD	01	linux/reiserfs_fs.h

Documentation/powerpc/cxlflash.txt

+Introduction
+============
+
+    The IBM Power architecture provides support for CAPI (Coherent
+    Accelerator Power Interface), which is available to certain PCIe slots
+    on Power 8 systems. CAPI can be thought of as a special tunneling
+    protocol through PCIe that allow PCIe adapters to look like special
+    purpose co-processors which can read or write an application's
+    memory and generate page faults. As a result, the host interface to
+    an adapter running in CAPI mode does not require the data buffers to
+    be mapped to the device's memory (IOMMU bypass) nor does it require
+    memory to be pinned.
+
+    On Linux, Coherent Accelerator (CXL) kernel services present CAPI
+    devices as a PCI device by implementing a virtual PCI host bridge.
+    This abstraction simplifies the infrastructure and programming
+    model, allowing for drivers to look similar to other native PCI
+    device drivers.
+
+    CXL provides a mechanism by which user space applications can
+    directly talk to a device (network or storage) bypassing the typical
+    kernel/device driver stack. The CXL Flash Adapter Driver enables a
+    user space application direct access to Flash storage.
+
+    The CXL Flash Adapter Driver is a kernel module that sits in the
+    SCSI stack as a low level device driver (below the SCSI disk and
+    protocol drivers) for the IBM CXL Flash Adapter. This driver is
+    responsible for the initialization of the adapter, setting up the
+    special path for user space access, and performing error recovery. It
+    communicates directly the Flash Accelerator Functional Unit (AFU)
+    as described in Documentation/powerpc/cxl.txt.
+
+    The cxlflash driver supports two, mutually exclusive, modes of
+    operation at the device (LUN) level:
+
+        - Any flash device (LUN) can be configured to be accessed as a
+          regular disk device (i.e.: /dev/sdc). This is the default mode.
+
+        - Any flash device (LUN) can be configured to be accessed from
+          user space with a special block library. This mode further
+          specifies the means of accessing the device and provides for
+          either raw access to the entire LUN (referred to as direct
+          or physical LUN access) or access to a kernel/AFU-mediated
+          partition of the LUN (referred to as virtual LUN access). The
+          segmentation of a disk device into virtual LUNs is assisted
+          by special translation services provided by the Flash AFU.
+
+Overview
+========
+
+    The Coherent Accelerator Interface Architecture (CAIA) introduces a
+    concept of a master context. A master typically has special privileges
+    granted to it by the kernel or hypervisor allowing it to perform AFU
+    wide management and control. The master may or may not be involved
+    directly in each user I/O, but at the minimum is involved in the
+    initial setup before the user application is allowed to send requests
+    directly to the AFU.
+
+    The CXL Flash Adapter Driver establishes a master context with the
+    AFU. It uses memory mapped I/O (MMIO) for this control and setup. The
+    Adapter Problem Space Memory Map looks like this:
+
+                     +-------------------------------+
+                     |    512 * 64 KB User MMIO      |
+                     |        (per context)          |
+                     |       User Accessible         |
+                     +-------------------------------+
+                     |    512 * 128 B per context    |
+                     |    Provisioning and Control   |
+                     |   Trusted Process accessible  |
+                     +-------------------------------+
+                     |         64 KB Global          |
+                     |   Trusted Process accessible  |
+                     +-------------------------------+
+
+    This driver configures itself into the SCSI software stack as an
+    adapter driver. The driver is the only entity that is considered a
+    Trusted Process to program the Provisioning and Control and Global
+    areas in the MMIO Space shown above.  The master context driver
+    discovers all LUNs attached to the CXL Flash adapter and instantiates
+    scsi block devices (/dev/sdb, /dev/sdc etc.) for each unique LUN
+    seen from each path.
+
+    Once these scsi block devices are instantiated, an application
+    written to a specification provided by the block library may get
+    access to the Flash from user space (without requiring a system call).
+
+    This master context driver also provides a series of ioctls for this
+    block library to enable this user space access.  The driver supports
+    two modes for accessing the block device.
+
+    The first mode is called a virtual mode. In this mode a single scsi
+    block device (/dev/sdb) may be carved up into any number of distinct
+    virtual LUNs. The virtual LUNs may be resized as long as the sum of
+    the sizes of all the virtual LUNs, along with the meta-data associated
+    with it does not exceed the physical capacity.
+
+    The second mode is called the physical mode. In this mode a single
+    block device (/dev/sdb) may be opened directly by the block library
+    and the entire space for the LUN is available to the application.
+
+    Only the physical mode provides persistence of the data.  i.e. The
+    data written to the block device will survive application exit and
+    restart and also reboot. The virtual LUNs do not persist (i.e. do
+    not survive after the application terminates or the system reboots).
+
+
+Block library API
+=================
+
+    Applications intending to get access to the CXL Flash from user
+    space should use the block library, as it abstracts the details of
+    interfacing directly with the cxlflash driver that are necessary for
+    performing administrative actions (i.e.: setup, tear down, resize).
+    The block library can be thought of as a 'user' of services,
+    implemented as IOCTLs, that are provided by the cxlflash driver
+    specifically for devices (LUNs) operating in user space access
+    mode. While it is not a requirement that applications understand
+    the interface between the block library and the cxlflash driver,
+    a high-level overview of each supported service (IOCTL) is provided
+    below.
+
+    The block library can be found on GitHub:
+    http://www.github.com/mikehollinger/ibmcapikv
+
+
+CXL Flash Driver IOCTLs
+=======================
+
+    Users, such as the block library, that wish to interface with a flash
+    device (LUN) via user space access need to use the services provided
+    by the cxlflash driver. As these services are implemented as ioctls,
+    a file descriptor handle must first be obtained in order to establish
+    the communication channel between a user and the kernel.  This file
+    descriptor is obtained by opening the device special file associated
+    with the scsi disk device (/dev/sdb) that was created during LUN
+    discovery. As per the location of the cxlflash driver within the
+    SCSI protocol stack, this open is actually not seen by the cxlflash
+    driver. Upon successful open, the user receives a file descriptor
+    (herein referred to as fd1) that should be used for issuing the
+    subsequent ioctls listed below.
+
+    The structure definitions for these IOCTLs are available in:
+    uapi/scsi/cxlflash_ioctl.h
+
+DK_CXLFLASH_ATTACH
+------------------
+
+    This ioctl obtains, initializes, and starts a context using the CXL
+    kernel services. These services specify a context id (u16) by which
+    to uniquely identify the context and its allocated resources. The
+    services additionally provide a second file descriptor (herein
+    referred to as fd2) that is used by the block library to initiate
+    memory mapped I/O (via mmap()) to the CXL flash device and poll for
+    completion events. This file descriptor is intentionally installed by
+    this driver and not the CXL kernel services to allow for intermediary
+    notification and access in the event of a non-user-initiated close(),
+    such as a killed process. This design point is described in further
+    detail in the description for the DK_CXLFLASH_DETACH ioctl.
+
+    There are a few important aspects regarding the "tokens" (context id
+    and fd2) that are provided back to the user:
+
+        - These tokens are only valid for the process under which they
+          were created. The child of a forked process cannot continue
+          to use the context id or file descriptor created by its parent.
+
+        - These tokens are only valid for the lifetime of the context and
+          the process under which they were created. Once either is
+          destroyed, the tokens are to be considered stale and subsequent
+          usage will result in errors.
+
+        - When a context is no longer needed, the user shall detach from
+          the context via the DK_CXLFLASH_DETACH ioctl.
+
+        - A close on fd2 will invalidate the tokens. This operation is not
+          required by the user.
+
+DK_CXLFLASH_USER_DIRECT
+-----------------------
+    This ioctl is responsible for transitioning the LUN to direct
+    (physical) mode access and configuring the AFU for direct access from
+    user space on a per-context basis. Additionally, the block size and
+    last logical block address (LBA) are returned to the user.
+
+    As mentioned previously, when operating in user space access mode,
+    LUNs may be accessed in whole or in part. Only one mode is allowed
+    at a time and if one mode is active (outstanding references exist),
+    requests to use the LUN in a different mode are denied.
+
+    The AFU is configured for direct access from user space by adding an
+    entry to the AFU's resource handle table. The index of the entry is
+    treated as a resource handle that is returned to the user. The user
+    is then able to use the handle to reference the LUN during I/O.
+
+DK_CXLFLASH_RELEASE
+-------------------
+    This ioctl is responsible for releasing a previously obtained
+    reference to either a physical or virtual LUN. This can be
+    thought of as the inverse of the DK_CXLFLASH_USER_DIRECT or
+    DK_CXLFLASH_USER_VIRTUAL ioctls. Upon success, the resource handle
+    is no longer valid and the entry in the resource handle table is
+    made available to be used again.
+
+    As part of the release process for virtual LUNs, the virtual LUN
+    is first resized to 0 to clear out and free the translation tables
+    associated with the virtual LUN reference.
+
+DK_CXLFLASH_DETACH
+------------------
+    This ioctl is responsible for unregistering a context with the
+    cxlflash driver and release outstanding resources that were
+    not explicitly released via the DK_CXLFLASH_RELEASE ioctl. Upon
+    success, all "tokens" which had been provided to the user from the
+    DK_CXLFLASH_ATTACH onward are no longer valid.
+
+DK_CXLFLASH_VERIFY
+------------------
+    This ioctl is used to detect various changes such as the capacity of
+    the disk changing, the number of LUNs visible changing, etc. In cases
+    where the changes affect the application (such as a LUN resize), the
+    cxlflash driver will report the changed state to the application.
+
+    The user calls in when they want to validate that a LUN hasn't been
+    changed in response to a check condition. As the user is operating out
+    of band from the kernel, they will see these types of events without
+    the kernel's knowledge. When encountered, the user's architected
+    behavior is to call in to this ioctl, indicating what they want to
+    verify and passing along any appropriate information. For now, only
+    verifying a LUN change (ie: size different) with sense data is
+    supported.
+
+DK_CXLFLASH_RECOVER_AFU
+-----------------------
+    This ioctl is used to drive recovery (if such an action is warranted)
+    of a specified user context. Any state associated with the user context
+    is re-established upon successful recovery.
+
+    User contexts are put into an error condition when the device needs to
+    be reset or is terminating. Users are notified of this error condition
+    by seeing all 0xF's on an MMIO read. Upon encountering this, the
+    architected behavior for a user is to call into this ioctl to recover
+    their context. A user may also call into this ioctl at any time to
+    check if the device is operating normally. If a failure is returned
+    from this ioctl, the user is expected to gracefully clean up their
+    context via release/detach ioctls. Until they do, the context they
+    hold is not relinquished. The user may also optionally exit the process
+    at which time the context/resources they held will be freed as part of
+    the release fop.
+
+DK_CXLFLASH_MANAGE_LUN
+----------------------
+    This ioctl is used to switch a LUN from a mode where it is available
+    for file-system access (legacy), to a mode where it is set aside for
+    exclusive user space access (superpipe). In case a LUN is visible
+    across multiple ports and adapters, this ioctl is used to uniquely
+    identify each LUN by its World Wide Node Name (WWNN).

drivers/scsi/cxlflash/Makefile

 obj-$(CONFIG_CXLFLASH) += cxlflash.o
-cxlflash-y += main.o
+cxlflash-y += main.o superpipe.o lunmgt.o

drivers/scsi/cxlflash/common.h

@@ -107,6 +107,17 @@ struct cxlflash_cfg {
 	struct pci_pool *cxlflash_cmd_pool;
 	struct pci_dev *parent_dev;
 
+	atomic_t recovery_threads;
+	struct mutex ctx_recovery_mutex;
+	struct mutex ctx_tbl_list_mutex;
+	struct ctx_info *ctx_tbl[MAX_CONTEXT];
+	struct list_head ctx_err_recovery; /* contexts w/ recovery pending */
+	struct file_operations cxl_fops;
+
+	atomic_t num_user_contexts;
+
+	struct list_head lluns; /* list of llun_info structs */
+
 	wait_queue_head_t tmf_waitq;
 	bool tmf_active;
 	wait_queue_head_t limbo_waitq;
@@ -182,4 +193,12 @@ int cxlflash_afu_reset(struct cxlflash_cfg *);
 struct afu_cmd *cxlflash_cmd_checkout(struct afu *);
 void cxlflash_cmd_checkin(struct afu_cmd *);
 int cxlflash_afu_sync(struct afu *, ctx_hndl_t, res_hndl_t, u8);
+void cxlflash_list_init(void);
+void cxlflash_term_global_luns(void);
+void cxlflash_free_errpage(void);
+int cxlflash_ioctl(struct scsi_device *, int, void __user *);
+void cxlflash_stop_term_user_contexts(struct cxlflash_cfg *);
+int cxlflash_mark_contexts_error(struct cxlflash_cfg *);
+void cxlflash_term_local_luns(struct cxlflash_cfg *);
+
 #endif /* ifndef _CXLFLASH_COMMON_H */

drivers/scsi/cxlflash/lunmgt.c

+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
+ *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2015 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <misc/cxl.h>
+#include <asm/unaligned.h>
+
+#include <scsi/scsi_host.h>
+#include <uapi/scsi/cxlflash_ioctl.h>
+
+#include "sislite.h"
+#include "common.h"
+#include "superpipe.h"
+
+/**
+ * create_local() - allocate and initialize a local LUN information structure
+ * @sdev:	SCSI device associated with LUN.
+ * @wwid:	World Wide Node Name for LUN.
+ *
+ * Return: Allocated local llun_info structure on success, NULL on failure
+ */
+static struct llun_info *create_local(struct scsi_device *sdev, u8 *wwid)
+{
+	struct llun_info *lli = NULL;
+
+	lli = kzalloc(sizeof(*lli), GFP_KERNEL);
+	if (unlikely(!lli)) {
+		pr_err("%s: could not allocate lli\n", __func__);
+		goto out;
+	}
+
+	lli->sdev = sdev;
+	lli->newly_created = true;
+	lli->host_no = sdev->host->host_no;
+
+	memcpy(lli->wwid, wwid, DK_CXLFLASH_MANAGE_LUN_WWID_LEN);
+out:
+	return lli;
+}
+
+/**
+ * create_global() - allocate and initialize a global LUN information structure
+ * @sdev:	SCSI device associated with LUN.
+ * @wwid:	World Wide Node Name for LUN.
+ *
+ * Return: Allocated global glun_info structure on success, NULL on failure
+ */
+static struct glun_info *create_global(struct scsi_device *sdev, u8 *wwid)
+{
+	struct glun_info *gli = NULL;
+
+	gli = kzalloc(sizeof(*gli), GFP_KERNEL);
+	if (unlikely(!gli)) {
+		pr_err("%s: could not allocate gli\n", __func__);
+		goto out;
+	}
+
+	mutex_init(&gli->mutex);
+	memcpy(gli->wwid, wwid, DK_CXLFLASH_MANAGE_LUN_WWID_LEN);
+out:
+	return gli;
+}
+
+/**
+ * refresh_local() - find and update local LUN information structure by WWID
+ * @cfg:	Internal structure associated with the host.
+ * @wwid:	WWID associated with LUN.
+ *
+ * When the LUN is found, mark it by updating it's newly_created field.
+ *
+ * Return: Found local lun_info structure on success, NULL on failure
+ * If a LUN with the WWID is found in the list, refresh it's state.
+ */
+static struct llun_info *refresh_local(struct cxlflash_cfg *cfg, u8 *wwid)
+{
+	struct llun_info *lli, *temp;
+
+	list_for_each_entry_safe(lli, temp, &cfg->lluns, list)
+		if (!memcmp(lli->wwid, wwid, DK_CXLFLASH_MANAGE_LUN_WWID_LEN)) {
+			lli->newly_created = false;
+			return lli;
+		}
+
+	return NULL;
+}
+
+/**
+ * lookup_global() - find a global LUN information structure by WWID
+ * @wwid:	WWID associated with LUN.
+ *
+ * Return: Found global lun_info structure on success, NULL on failure
+ */
+static struct glun_info *lookup_global(u8 *wwid)
+{
+	struct glun_info *gli, *temp;
+
+	list_for_each_entry_safe(gli, temp, &global.gluns, list)
+		if (!memcmp(gli->wwid, wwid, DK_CXLFLASH_MANAGE_LUN_WWID_LEN))
+			return gli;
+
+	return NULL;
+}
+
+/**
+ * find_and_create_lun() - find or create a local LUN information structure
+ * @sdev:	SCSI device associated with LUN.
+ * @wwid:	WWID associated with LUN.
+ *
+ * The LUN is kept both in a local list (per adapter) and in a global list
+ * (across all adapters). Certain attributes of the LUN are local to the
+ * adapter (such as index, port selection mask etc.).
+ * The block allocation map is shared across all adapters (i.e. associated
+ * wih the global list). Since different attributes are associated with
+ * the per adapter and global entries, allocate two separate structures for each
+ * LUN (one local, one global).
+ *
+ * Keep a pointer back from the local to the global entry.
+ *
+ * Return: Found/Allocated local lun_info structure on success, NULL on failure
+ */
+static struct llun_info *find_and_create_lun(struct scsi_device *sdev, u8 *wwid)
+{
+	struct llun_info *lli = NULL;
+	struct glun_info *gli = NULL;
+	struct Scsi_Host *shost = sdev->host;
+	struct cxlflash_cfg *cfg = shost_priv(shost);
+
+	mutex_lock(&global.mutex);
+	if (unlikely(!wwid))
+		goto out;
+
+	lli = refresh_local(cfg, wwid);
+	if (lli)
+		goto out;
+
+	lli = create_local(sdev, wwid);
+	if (unlikely(!lli))
+		goto out;
+
+	gli = lookup_global(wwid);
+	if (gli) {
+		lli->parent = gli;
+		list_add(&lli->list, &cfg->lluns);
+		goto out;
+	}
+
+	gli = create_global(sdev, wwid);
+	if (unlikely(!gli)) {
+		kfree(lli);
+		lli = NULL;
+		goto out;
+	}
+
+	lli->parent = gli;
+	list_add(&lli->list, &cfg->lluns);
+
+	list_add(&gli->list, &global.gluns);
+
+out:
+	mutex_unlock(&global.mutex);
+	pr_debug("%s: returning %p\n", __func__, lli);
+	return lli;
+}
+
+/**
+ * cxlflash_term_local_luns() - Delete all entries from local LUN list, free.
+ * @cfg:	Internal structure associated with the host.
+ */
+void cxlflash_term_local_luns(struct cxlflash_cfg *cfg)
+{
+	struct llun_info *lli, *temp;
+
+	mutex_lock(&global.mutex);
+	list_for_each_entry_safe(lli, temp, &cfg->lluns, list) {
+		list_del(&lli->list);
+		kfree(lli);
+	}
+	mutex_unlock(&global.mutex);
+}
+
+/**
+ * cxlflash_list_init() - initializes the global LUN list
+ */
+void cxlflash_list_init(void)
+{
+	INIT_LIST_HEAD(&global.gluns);
+	mutex_init(&global.mutex);
+	global.err_page = NULL;
+}
+
+/**
+ * cxlflash_term_global_luns() - frees resources associated with global LUN list
+ */
+void cxlflash_term_global_luns(void)
+{
+	struct glun_info *gli, *temp;
+
+	mutex_lock(&global.mutex);
+	list_for_each_entry_safe(gli, temp, &global.gluns, list) {
+		list_del(&gli->list);
+		kfree(gli);
+	}
+	mutex_unlock(&global.mutex);
+}
+
+/**
+ * cxlflash_manage_lun() - handles LUN management activities
+ * @sdev:	SCSI device associated with LUN.
+ * @manage:	Manage ioctl data structure.
+ *
+ * This routine is used to notify the driver about a LUN's WWID and associate
+ * SCSI devices (sdev) with a global LUN instance. Additionally it serves to
+ * change a LUN's operating mode: legacy or superpipe.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int cxlflash_manage_lun(struct scsi_device *sdev,
+			struct dk_cxlflash_manage_lun *manage)
+{
+	int rc = 0;
+	struct llun_info *lli = NULL;
+	u64 flags = manage->hdr.flags;
+	u32 chan = sdev->channel;
+
+	lli = find_and_create_lun(sdev, manage->wwid);
+	pr_debug("%s: ENTER: WWID = %016llX%016llX, flags = %016llX li = %p\n",
+		 __func__, get_unaligned_le64(&manage->wwid[0]),
+		 get_unaligned_le64(&manage->wwid[8]),
+		 manage->hdr.flags, lli);
+	if (unlikely(!lli)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (flags & DK_CXLFLASH_MANAGE_LUN_ENABLE_SUPERPIPE) {
+		if (lli->newly_created)
+			lli->port_sel = CHAN2PORT(chan);
+		else
+			lli->port_sel = BOTH_PORTS;
+		/* Store off lun in unpacked, AFU-friendly format */
+		lli->lun_id[chan] = lun_to_lunid(sdev->lun);
+		sdev->hostdata = lli;
+	} else if (flags & DK_CXLFLASH_MANAGE_LUN_DISABLE_SUPERPIPE) {
+		if (lli->parent->mode != MODE_NONE)
+			rc = -EBUSY;
+		else
+			sdev->hostdata = NULL;
+	}
+
+out:
+	pr_debug("%s: returning rc=%d\n", __func__, rc);
+	return rc;
+}

drivers/scsi/cxlflash/main.c

@@ -23,6 +23,7 @@
 
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
+#include <uapi/scsi/cxlflash_ioctl.h>
 
 #include "main.h"
 #include "sislite.h"
@@ -519,7 +520,7 @@ static int cxlflash_eh_host_reset_handler(struct scsi_cmnd *scp)
 	case STATE_NORMAL:
 		cfg->state = STATE_LIMBO;
 		scsi_block_requests(cfg->host);
-
+		cxlflash_mark_contexts_error(cfg);
 		rcr = cxlflash_afu_reset(cfg);
 		if (rcr) {
 			rc = FAILED;
@@ -662,6 +663,21 @@ static ssize_t cxlflash_store_lun_mode(struct device *dev,
 	return count;
 }
 
+/**
+ * cxlflash_show_ioctl_version() - presents the current ioctl version of the host
+ * @dev:	Generic device associated with the host.
+ * @attr:	Device attribute representing the ioctl version.
+ * @buf:	Buffer of length PAGE_SIZE to report back the ioctl version.
+ *
+ * Return: The size of the ASCII string returned in @buf.
+ */
+static ssize_t cxlflash_show_ioctl_version(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%u\n", DK_CXLFLASH_VERSION_0);
+}
+
 /**
  * cxlflash_show_dev_mode() - presents the current mode of the device
  * @dev:	Generic device associated with the device.
@@ -700,11 +716,13 @@ static DEVICE_ATTR(port0, S_IRUGO, cxlflash_show_port_status, NULL);
 static DEVICE_ATTR(port1, S_IRUGO, cxlflash_show_port_status, NULL);
 static DEVICE_ATTR(lun_mode, S_IRUGO | S_IWUSR, cxlflash_show_lun_mode,
 		   cxlflash_store_lun_mode);
+static DEVICE_ATTR(ioctl_version, S_IRUGO, cxlflash_show_ioctl_version, NULL);
 
 static struct device_attribute *cxlflash_host_attrs[] = {
 	&dev_attr_port0,
 	&dev_attr_port1,
 	&dev_attr_lun_mode,
+	&dev_attr_ioctl_version,
 	NULL
 };
 
@@ -725,6 +743,7 @@ static struct scsi_host_template driver_template = {
 	.module = THIS_MODULE,
 	.name = CXLFLASH_ADAPTER_NAME,
 	.info = cxlflash_driver_info,
+	.ioctl = cxlflash_ioctl,
 	.proc_name = CXLFLASH_NAME,
 	.queuecommand = cxlflash_queuecommand,
 	.eh_device_reset_handler = cxlflash_eh_device_reset_handler,
@@ -872,9 +891,11 @@ static void cxlflash_remove(struct pci_dev *pdev)
 	spin_unlock_irqrestore(&cfg->tmf_waitq.lock, lock_flags);
 
 	cfg->state = STATE_FAILTERM;
+	cxlflash_stop_term_user_contexts(cfg);
 
 	switch (cfg->init_state) {
 	case INIT_STATE_SCSI:
+		cxlflash_term_local_luns(cfg);
 		scsi_remove_host(cfg->host);
 		scsi_host_put(cfg->host);
 		/* Fall through */
@@ -2274,6 +2295,10 @@ static int cxlflash_probe(struct pci_dev *pdev,
 	INIT_WORK(&cfg->work_q, cxlflash_worker_thread);
 	cfg->lr_state = LINK_RESET_INVALID;
 	cfg->lr_port = -1;
+	mutex_init(&cfg->ctx_tbl_list_mutex);
+	mutex_init(&cfg->ctx_recovery_mutex);
+	INIT_LIST_HEAD(&cfg->ctx_err_recovery);
+	INIT_LIST_HEAD(&cfg->lluns);
 
 	pci_set_drvdata(pdev, cfg);
 
@@ -2335,6 +2360,7 @@ static int cxlflash_probe(struct pci_dev *pdev,
 static pci_ers_result_t cxlflash_pci_error_detected(struct pci_dev *pdev,
 						    pci_channel_state_t state)
 {
+	int rc = 0;
 	struct cxlflash_cfg *cfg = pci_get_drvdata(pdev);
 	struct device *dev = &cfg->dev->dev;
 
@@ -2346,7 +2372,10 @@ static pci_ers_result_t cxlflash_pci_error_detected(struct pci_dev *pdev,
 
 		/* Turn off legacy I/O */
 		scsi_block_requests(cfg->host);
-
+		rc = cxlflash_mark_contexts_error(cfg);
+		if (unlikely(rc))
+			dev_err(dev, "%s: Failed to mark user contexts!(%d)\n",
+				__func__, rc);
 		term_mc(cfg, UNDO_START);
 		stop_afu(cfg);
 
@@ -2431,6 +2460,8 @@ static int __init init_cxlflash(void)
 	pr_info("%s: IBM Power CXL Flash Adapter: %s\n",
 		__func__, CXLFLASH_DRIVER_DATE);
 
+	cxlflash_list_init();
+
 	return pci_register_driver(&cxlflash_driver);
 }
 
@@ -2439,6 +2470,9 @@ static int __init init_cxlflash(void)
  */
 static void __exit exit_cxlflash(void)
 {
+	cxlflash_term_global_luns();
+	cxlflash_free_errpage();
+
 	pci_unregister_driver(&cxlflash_driver);
 }
 

drivers/scsi/cxlflash/sislite.h

@@ -409,7 +409,10 @@ struct sisl_lxt_entry {
 
 };
 
-/* Per the SISlite spec, RHT entries are to be 16-byte aligned */
+/*
+ * RHT - Resource Handle Table
+ * Per the SISlite spec, RHT entries are to be 16-byte aligned
+ */
 struct sisl_rht_entry {
 	struct sisl_lxt_entry *lxt_start;
 	u32 lxt_cnt;

drivers/scsi/cxlflash/superpipe.h

+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
+ *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2015 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _CXLFLASH_SUPERPIPE_H
+#define _CXLFLASH_SUPERPIPE_H
+
+extern struct cxlflash_global global;
+
+/*
+ * Terminology: use afu (and not adapter) to refer to the HW.
+ * Adapter is the entire slot and includes PSL out of which
+ * only the AFU is visible to user space.
+ */
+
+/* Chunk size parms: note sislite minimum chunk size is
+   0x10000 LBAs corresponding to a NMASK or 16.
+*/
+#define MC_CHUNK_SIZE     (1 << MC_RHT_NMASK)	/* in LBAs */
+
+#define MC_DISCOVERY_TIMEOUT 5  /* 5 secs */
+
+#define CHAN2PORT(_x)	((_x) + 1)
+
+enum lun_mode {
+	MODE_NONE = 0,
+	MODE_PHYSICAL
+};
+
+/* Global (entire driver, spans adapters) lun_info structure */
+struct glun_info {
+	u64 max_lba;		/* from read cap(16) */
+	u32 blk_len;		/* from read cap(16) */
+	enum lun_mode mode;	/* NONE, PHYSICAL */
+	int users;		/* Number of users w/ references to LUN */
+
+	u8 wwid[16];
+
+	struct mutex mutex;
+
+	struct list_head list;
+};
+
+/* Local (per-adapter) lun_info structure */
+struct llun_info {
+	u64 lun_id[CXLFLASH_NUM_FC_PORTS]; /* from REPORT_LUNS */
+	u32 lun_index;		/* Index in the LUN table */
+	u32 host_no;		/* host_no from Scsi_host */
+	u32 port_sel;		/* What port to use for this LUN */
+	bool newly_created;	/* Whether the LUN was just discovered */
+
+	u8 wwid[16];		/* Keep a duplicate copy here? */
+
+	struct glun_info *parent; /* Pointer to entry in global LUN structure */
+	struct scsi_device *sdev;
+	struct list_head list;
+};
+
+struct lun_access {
+	struct llun_info *lli;
+	struct scsi_device *sdev;
+	struct list_head list;
+};
+
+enum ctx_ctrl {
+	CTX_CTRL_CLONE		= (1 << 1),
+	CTX_CTRL_ERR		= (1 << 2),
+	CTX_CTRL_ERR_FALLBACK	= (1 << 3),
+	CTX_CTRL_NOPID		= (1 << 4),
+	CTX_CTRL_FILE		= (1 << 5)
+};
+
+#define ENCODE_CTXID(_ctx, _id)	(((((u64)_ctx) & 0xFFFFFFFF0) << 28) | _id)
+#define DECODE_CTXID(_val)	(_val & 0xFFFFFFFF)
+
+struct ctx_info {
+	struct sisl_ctrl_map *ctrl_map; /* initialized at startup */
+	struct sisl_rht_entry *rht_start; /* 1 page (req'd for alignment),
+					     alloc/free on attach/detach */
+	u32 rht_out;		/* Number of checked out RHT entries */
+	u32 rht_perms;		/* User-defined permissions for RHT entries */
+	struct llun_info **rht_lun;       /* Mapping of RHT entries to LUNs */
+
+	struct cxl_ioctl_start_work work;
+	u64 ctxid;
+	int lfd;
+	pid_t pid;
+	bool unavail;
+	bool err_recovery_active;
+	struct mutex mutex; /* Context protection */
+	struct cxl_context *ctx;
+	struct list_head luns;	/* LUNs attached to this context */
+	const struct vm_operations_struct *cxl_mmap_vmops;
+	struct file *file;
+	struct list_head list; /* Link contexts in error recovery */
+};
+
+struct cxlflash_global {
+	struct mutex mutex;
+	struct list_head gluns;/* list of glun_info structs */
+	struct page *err_page; /* One page of all 0xF for error notification */
+};
+
+int cxlflash_disk_release(struct scsi_device *, struct dk_cxlflash_release *);
+int _cxlflash_disk_release(struct scsi_device *, struct ctx_info *,
+			   struct dk_cxlflash_release *);
+
+int cxlflash_lun_attach(struct glun_info *, enum lun_mode, bool);
+void cxlflash_lun_detach(struct glun_info *);
+
+struct ctx_info *get_context(struct cxlflash_cfg *, u64, void *, enum ctx_ctrl);
+void put_context(struct ctx_info *);
+
+struct sisl_rht_entry *get_rhte(struct ctx_info *, res_hndl_t,
+				struct llun_info *);
+
+struct sisl_rht_entry *rhte_checkout(struct ctx_info *, struct llun_info *);
+void rhte_checkin(struct ctx_info *, struct sisl_rht_entry *);
+
+int cxlflash_manage_lun(struct scsi_device *, struct dk_cxlflash_manage_lun *);
+
+#endif /* ifndef _CXLFLASH_SUPERPIPE_H */

include/uapi/scsi/Kbuild

@@ -3,3 +3,4 @@ header-y += fc/
 header-y += scsi_bsg_fc.h
 header-y += scsi_netlink.h
 header-y += scsi_netlink_fc.h
+header-y += cxlflash_ioctl.h

include/uapi/scsi/cxlflash_ioctl.h

+/*
+ * CXL Flash Device Driver
+ *
+ * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
+ *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
+ *
+ * Copyright (C) 2015 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _CXLFLASH_IOCTL_H
+#define _CXLFLASH_IOCTL_H
+
+#include <linux/types.h>
+
+/*
+ * Structure and flag definitions CXL Flash superpipe ioctls
+ */
+
+#define DK_CXLFLASH_VERSION_0	0
+
+struct dk_cxlflash_hdr {
+	__u16 version;			/* Version data */
+	__u16 rsvd[3];			/* Reserved for future use */
+	__u64 flags;			/* Input flags */
+	__u64 return_flags;		/* Returned flags */
+};
+
+/*
+ * Notes:
+ * -----
+ * The 'context_id' field of all ioctl structures contains the context
+ * identifier for a context in the lower 32-bits (upper 32-bits are not
+ * to be used when identifying a context to the AFU). That said, the value
+ * in its entirety (all 64-bits) is to be treated as an opaque cookie and
+ * should be presented as such when issuing ioctls.
+ *
+ * For DK_CXLFLASH_ATTACH ioctl, user specifies read/write access
+ * permissions via the O_RDONLY, O_WRONLY, and O_RDWR flags defined in
+ * the fcntl.h header file.
+ */
+#define DK_CXLFLASH_ATTACH_REUSE_CONTEXT	0x8000000000000000ULL
+
+struct dk_cxlflash_attach {
+	struct dk_cxlflash_hdr hdr;	/* Common fields */
+	__u64 num_interrupts;		/* Requested number of interrupts */
+	__u64 context_id;		/* Returned context */
+	__u64 mmio_size;		/* Returned size of MMIO area */
+	__u64 block_size;		/* Returned block size, in bytes */
+	__u64 adap_fd;			/* Returned adapter file descriptor */
+	__u64 last_lba;			/* Returned last LBA on the device */
+	__u64 max_xfer;			/* Returned max transfer size, blocks */
+	__u64 reserved[8];		/* Reserved for future use */
+};
+
+struct dk_cxlflash_detach {
+	struct dk_cxlflash_hdr hdr;	/* Common fields */
+	__u64 context_id;		/* Context to detach */
+	__u64 reserved[8];		/* Reserved for future use */
+};
+
+struct dk_cxlflash_udirect {
+	struct dk_cxlflash_hdr hdr;	/* Common fields */
+	__u64 context_id;		/* Context to own physical resources */
+	__u64 rsrc_handle;		/* Returned resource handle */
+	__u64 last_lba;			/* Returned last LBA on the device */
+	__u64 reserved[8];		/* Reserved for future use */
+};
+
+struct dk_cxlflash_release {
+	struct dk_cxlflash_hdr hdr;	/* Common fields */
+	__u64 context_id;		/* Context owning resources */
+	__u64 rsrc_handle;		/* Resource handle to release */
+	__u64 reserved[8];		/* Reserved for future use */
+};
+
+#define DK_CXLFLASH_VERIFY_SENSE_LEN	18
+#define DK_CXLFLASH_VERIFY_HINT_SENSE	0x8000000000000000ULL
+
+struct dk_cxlflash_verify {
+	struct dk_cxlflash_hdr hdr;	/* Common fields */
+	__u64 context_id;		/* Context owning resources to verify */
+	__u64 rsrc_handle;		/* Resource handle of LUN */
+	__u64 hint;			/* Reasons for verify */
+	__u64 last_lba;			/* Returned last LBA of device */
+	__u8 sense_data[DK_CXLFLASH_VERIFY_SENSE_LEN]; /* SCSI sense data */
+	__u8 pad[6];			/* Pad to next 8-byte boundary */
+	__u64 reserved[8];		/* Reserved for future use */
+};
+
+#define DK_CXLFLASH_RECOVER_AFU_CONTEXT_RESET	0x8000000000000000ULL
+
+struct dk_cxlflash_recover_afu {
+	struct dk_cxlflash_hdr hdr;	/* Common fields */
+	__u64 reason;			/* Reason for recovery request */
+	__u64 context_id;		/* Context to recover / updated ID */
+	__u64 mmio_size;		/* Returned size of MMIO area */
+	__u64 adap_fd;			/* Returned adapter file descriptor */
+	__u64 reserved[8];		/* Reserved for future use */
+};
+
+#define DK_CXLFLASH_MANAGE_LUN_WWID_LEN			16
+#define DK_CXLFLASH_MANAGE_LUN_ENABLE_SUPERPIPE		0x8000000000000000ULL
+#define DK_CXLFLASH_MANAGE_LUN_DISABLE_SUPERPIPE	0x4000000000000000ULL
+#define DK_CXLFLASH_MANAGE_LUN_ALL_PORTS_ACCESSIBLE	0x2000000000000000ULL
+
+struct dk_cxlflash_manage_lun {
+	struct dk_cxlflash_hdr hdr;			/* Common fields */
+	__u8 wwid[DK_CXLFLASH_MANAGE_LUN_WWID_LEN];	/* Page83 WWID, NAA-6 */
+	__u64 reserved[8];				/* Rsvd, future use */
+};
+
+union cxlflash_ioctls {
+	struct dk_cxlflash_attach attach;
+	struct dk_cxlflash_detach detach;
+	struct dk_cxlflash_udirect udirect;
+	struct dk_cxlflash_release release;
+	struct dk_cxlflash_verify verify;
+	struct dk_cxlflash_recover_afu recover_afu;
+	struct dk_cxlflash_manage_lun manage_lun;
+};
+
+#define MAX_CXLFLASH_IOCTL_SZ	(sizeof(union cxlflash_ioctls))
+
+#define CXL_MAGIC 0xCA
+#define CXL_IOWR(_n, _s)	_IOWR(CXL_MAGIC, _n, struct _s)
+
+#define DK_CXLFLASH_ATTACH		CXL_IOWR(0x80, dk_cxlflash_attach)
+#define DK_CXLFLASH_USER_DIRECT		CXL_IOWR(0x81, dk_cxlflash_udirect)
+#define DK_CXLFLASH_RELEASE		CXL_IOWR(0x82, dk_cxlflash_release)
+#define DK_CXLFLASH_DETACH		CXL_IOWR(0x83, dk_cxlflash_detach)
+#define DK_CXLFLASH_VERIFY		CXL_IOWR(0x84, dk_cxlflash_verify)
+#define DK_CXLFLASH_RECOVER_AFU		CXL_IOWR(0x85, dk_cxlflash_recover_afu)
+#define DK_CXLFLASH_MANAGE_LUN		CXL_IOWR(0x86, dk_cxlflash_manage_lun)
+
+#endif /* ifndef _CXLFLASH_IOCTL_H */