[PATCH RFC v3 13/14] dmaengine: idxd: add char driver to expose submission portal to userland

From: Dave Jiang
Date: Tue Dec 17 2019 - 18:34:31 EST


Create a char device region that will allow acquisition of user portals in
order to allow applications to submit DMA operations. A char device will be
created per work queue that gets exposed. The workqueue type "user"
is used to mark a work queue for user char device. For example if the
workqueue 0 of DSA device 0 is marked for char device, then a device node
of /dev/dsa/wq0.0 will be created.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
drivers/dma/idxd/Makefile | 2
drivers/dma/idxd/cdev.c | 302 +++++++++++++++++++++++++++++++++++++++++++++
drivers/dma/idxd/device.c | 2
drivers/dma/idxd/idxd.h | 38 ++++++
drivers/dma/idxd/init.c | 10 +
drivers/dma/idxd/irq.c | 18 +++
drivers/dma/idxd/submit.c | 4 -
drivers/dma/idxd/sysfs.c | 52 +++++++-
8 files changed, 423 insertions(+), 5 deletions(-)
create mode 100644 drivers/dma/idxd/cdev.c

diff --git a/drivers/dma/idxd/Makefile b/drivers/dma/idxd/Makefile
index a036ba0e77d2..8978b898d777 100644
--- a/drivers/dma/idxd/Makefile
+++ b/drivers/dma/idxd/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_INTEL_IDXD) += idxd.o
-idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o
+idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
new file mode 100644
index 000000000000..1d7347825b95
--- /dev/null
+++ b/drivers/dma/idxd/cdev.c
@@ -0,0 +1,302 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/device.h>
+#include <linux/sched/task.h>
+#include <linux/intel-svm.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <uapi/linux/idxd.h>
+#include "registers.h"
+#include "idxd.h"
+
+struct idxd_cdev_context {
+ const char *name;
+ dev_t devt;
+ struct ida minor_ida;
+};
+
+/*
+ * ictx is an array based off of accelerator types. enum idxd_type
+ * is used as index
+ */
+static struct idxd_cdev_context ictx[IDXD_TYPE_MAX] = {
+ { .name = "dsa" },
+};
+
+struct idxd_user_context {
+ struct idxd_wq *wq;
+ struct task_struct *task;
+ unsigned int flags;
+};
+
+enum idxd_cdev_cleanup {
+ CDEV_NORMAL = 0,
+ CDEV_FAILED,
+};
+
+static void idxd_cdev_dev_release(struct device *dev)
+{
+ dev_dbg(dev, "releasing cdev device\n");
+ kfree(dev);
+}
+
+static struct device_type idxd_cdev_device_type = {
+ .name = "idxd_cdev",
+ .release = idxd_cdev_dev_release,
+};
+
+static inline struct idxd_cdev *inode_idxd_cdev(struct inode *inode)
+{
+ struct cdev *cdev = inode->i_cdev;
+
+ return container_of(cdev, struct idxd_cdev, cdev);
+}
+
+static inline struct idxd_wq *idxd_cdev_wq(struct idxd_cdev *idxd_cdev)
+{
+ return container_of(idxd_cdev, struct idxd_wq, idxd_cdev);
+}
+
+static inline struct idxd_wq *inode_wq(struct inode *inode)
+{
+ return idxd_cdev_wq(inode_idxd_cdev(inode));
+}
+
+static int idxd_cdev_open(struct inode *inode, struct file *filp)
+{
+ struct idxd_user_context *ctx;
+ struct idxd_device *idxd;
+ struct idxd_wq *wq;
+ struct device *dev;
+ struct idxd_cdev *idxd_cdev;
+
+ wq = inode_wq(inode);
+ idxd = wq->idxd;
+ dev = &idxd->pdev->dev;
+ idxd_cdev = &wq->idxd_cdev;
+
+ dev_dbg(dev, "%s called\n", __func__);
+
+ if (idxd_wq_refcount(wq) > 1 && wq_dedicated(wq))
+ return -EBUSY;
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->wq = wq;
+ filp->private_data = ctx;
+ idxd_wq_get(wq);
+ return 0;
+}
+
+static int idxd_cdev_release(struct inode *node, struct file *filep)
+{
+ struct idxd_user_context *ctx = filep->private_data;
+ struct idxd_wq *wq = ctx->wq;
+ struct idxd_device *idxd = wq->idxd;
+ struct device *dev = &idxd->pdev->dev;
+
+ dev_dbg(dev, "%s called\n", __func__);
+ filep->private_data = NULL;
+
+ kfree(ctx);
+ idxd_wq_put(wq);
+ return 0;
+}
+
+static int check_vma(struct idxd_wq *wq, struct vm_area_struct *vma,
+ const char *func)
+{
+ struct device *dev = &wq->idxd->pdev->dev;
+
+ if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) {
+ dev_info_ratelimited(dev,
+ "%s: %s: mapping too large: %lu\n",
+ current->comm, func,
+ vma->vm_end - vma->vm_start);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int idxd_cdev_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+ struct idxd_user_context *ctx = filp->private_data;
+ struct idxd_wq *wq = ctx->wq;
+ struct idxd_device *idxd = wq->idxd;
+ struct pci_dev *pdev = idxd->pdev;
+ phys_addr_t base = pci_resource_start(pdev, IDXD_WQ_BAR);
+ unsigned long pfn;
+ int rc;
+
+ dev_dbg(&pdev->dev, "%s called\n", __func__);
+ rc = check_vma(wq, vma, __func__);
+
+ vma->vm_flags |= VM_DONTCOPY;
+ pfn = (base + idxd_get_wq_portal_full_offset(wq->id,
+ IDXD_PORTAL_LIMITED)) >> PAGE_SHIFT;
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ vma->vm_private_data = ctx;
+
+ return io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE,
+ vma->vm_page_prot);
+}
+
+static __poll_t idxd_cdev_poll(struct file *filp,
+ struct poll_table_struct *wait)
+{
+ struct idxd_user_context *ctx = filp->private_data;
+ struct idxd_wq *wq = ctx->wq;
+ struct idxd_device *idxd = wq->idxd;
+ struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+ unsigned long flags;
+ __poll_t out = 0;
+
+ poll_wait(filp, &idxd_cdev->err_queue, wait);
+ spin_lock_irqsave(&idxd->dev_lock, flags);
+ if (idxd->sw_err.valid)
+ out = EPOLLIN | EPOLLRDNORM;
+ spin_unlock_irqrestore(&idxd->dev_lock, flags);
+
+ return out;
+}
+
+static const struct file_operations idxd_cdev_fops = {
+ .owner = THIS_MODULE,
+ .open = idxd_cdev_open,
+ .release = idxd_cdev_release,
+ .mmap = idxd_cdev_mmap,
+ .poll = idxd_cdev_poll,
+};
+
+int idxd_cdev_get_major(struct idxd_device *idxd)
+{
+ return MAJOR(ictx[idxd->type].devt);
+}
+
+static int idxd_wq_cdev_dev_setup(struct idxd_wq *wq)
+{
+ struct idxd_device *idxd = wq->idxd;
+ struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+ struct idxd_cdev_context *cdev_ctx;
+ struct device *dev;
+ int minor, rc;
+
+ idxd_cdev->dev = kzalloc(sizeof(*idxd_cdev->dev), GFP_KERNEL);
+ if (!idxd_cdev->dev)
+ return -ENOMEM;
+
+ dev = idxd_cdev->dev;
+ dev->parent = &idxd->pdev->dev;
+ dev_set_name(dev, "%s/wq%u.%u", idxd_get_dev_name(idxd),
+ idxd->id, wq->id);
+ dev->bus = idxd_get_bus_type(idxd);
+
+ cdev_ctx = &ictx[wq->idxd->type];
+ minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL);
+ if (minor < 0) {
+ rc = minor;
+ goto ida_err;
+ }
+
+ dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
+ dev->type = &idxd_cdev_device_type;
+ rc = device_register(dev);
+ if (rc < 0) {
+ dev_err(&idxd->pdev->dev, "device register failed\n");
+ put_device(dev);
+ goto dev_reg_err;
+ }
+ idxd_cdev->minor = minor;
+
+ return 0;
+
+ dev_reg_err:
+ ida_simple_remove(&cdev_ctx->minor_ida, MINOR(dev->devt));
+ ida_err:
+ kfree(dev);
+ idxd_cdev->dev = NULL;
+ return rc;
+}
+
+static void idxd_wq_cdev_cleanup(struct idxd_wq *wq,
+ enum idxd_cdev_cleanup cdev_state)
+{
+ struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+ struct idxd_cdev_context *cdev_ctx;
+
+ cdev_ctx = &ictx[wq->idxd->type];
+ if (cdev_state == CDEV_NORMAL)
+ cdev_del(&idxd_cdev->cdev);
+ device_unregister(idxd_cdev->dev);
+ /*
+ * The device_type->release() will be called on the device and free
+ * the allocated struct device. We can just forget it.
+ */
+ ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor);
+ idxd_cdev->dev = NULL;
+ idxd_cdev->minor = -1;
+}
+
+int idxd_wq_add_cdev(struct idxd_wq *wq)
+{
+ struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
+ struct cdev *cdev = &idxd_cdev->cdev;
+ struct device *dev;
+ int rc;
+
+ rc = idxd_wq_cdev_dev_setup(wq);
+ if (rc < 0)
+ return rc;
+
+ dev = idxd_cdev->dev;
+ cdev_init(cdev, &idxd_cdev_fops);
+ cdev_set_parent(cdev, &dev->kobj);
+ rc = cdev_add(cdev, dev->devt, 1);
+ if (rc) {
+ dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc);
+ idxd_wq_cdev_cleanup(wq, CDEV_FAILED);
+ return rc;
+ }
+
+ init_waitqueue_head(&idxd_cdev->err_queue);
+ return 0;
+}
+
+void idxd_wq_del_cdev(struct idxd_wq *wq)
+{
+ idxd_wq_cdev_cleanup(wq, CDEV_NORMAL);
+}
+
+int idxd_cdev_register(void)
+{
+ int rc, i;
+
+ for (i = 0; i < IDXD_TYPE_MAX; i++) {
+ ida_init(&ictx[i].minor_ida);
+ rc = alloc_chrdev_region(&ictx[i].devt, 0, MINORMASK,
+ ictx[i].name);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+
+void idxd_cdev_remove(void)
+{
+ int i;
+
+ for (i = 0; i < IDXD_TYPE_MAX; i++) {
+ unregister_chrdev_region(ictx[i].devt, MINORMASK);
+ ida_destroy(&ictx[i].minor_ida);
+ }
+}
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 49638d3a2151..fd33e2985e95 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -545,7 +545,7 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
wq->wqcfg.wq_thresh = wq->threshold;

/* byte 8-11 */
- wq->wqcfg.priv = 1; /* kernel, therefore priv */
+ wq->wqcfg.priv = !!(wq->type == IDXD_WQT_KERNEL);
wq->wqcfg.mode = 1;

wq->wqcfg.priority = wq->priority;
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index fc1634e689cf..23bf12ad0af4 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -7,6 +7,7 @@
#include <linux/dmaengine.h>
#include <linux/percpu-rwsem.h>
#include <linux/wait.h>
+#include <linux/cdev.h>
#include "registers.h"

#define IDXD_DRIVER_VERSION "1.00"
@@ -63,6 +64,14 @@ enum idxd_wq_flag {
enum idxd_wq_type {
IDXD_WQT_NONE = 0,
IDXD_WQT_KERNEL,
+ IDXD_WQT_USER,
+};
+
+struct idxd_cdev {
+ struct cdev cdev;
+ struct device *dev;
+ int minor;
+ struct wait_queue_head err_queue;
};

#define IDXD_ALLOCATED_BATCH_SIZE 128U
@@ -72,6 +81,7 @@ enum idxd_wq_type {
struct idxd_wq {
void __iomem *dportal;
struct device conf_dev;
+ struct idxd_cdev idxd_cdev;
struct idxd_device *idxd;
int id;
enum idxd_wq_type type;
@@ -139,6 +149,7 @@ struct idxd_device {
enum idxd_device_state state;
unsigned long flags;
int id;
+ int major;

struct pci_dev *pdev;
void __iomem *reg_base;
@@ -192,11 +203,29 @@ struct idxd_desc {
#define confdev_to_idxd(dev) container_of(dev, struct idxd_device, conf_dev)
#define confdev_to_wq(dev) container_of(dev, struct idxd_wq, conf_dev)

+extern struct bus_type dsa_bus_type;
+
static inline bool wq_dedicated(struct idxd_wq *wq)
{
return test_bit(WQ_FLAG_DEDICATED, &wq->flags);
}

+enum idxd_portal_prot {
+ IDXD_PORTAL_UNLIMITED = 0,
+ IDXD_PORTAL_LIMITED,
+};
+
+static inline int idxd_get_wq_portal_offset(enum idxd_portal_prot prot)
+{
+ return prot * 0x1000;
+}
+
+static inline int idxd_get_wq_portal_full_offset(int wq_id,
+ enum idxd_portal_prot prot)
+{
+ return ((wq_id * 4) << PAGE_SHIFT) + idxd_get_wq_portal_offset(prot);
+}
+
static inline void idxd_set_type(struct idxd_device *idxd)
{
struct pci_dev *pdev = idxd->pdev;
@@ -229,6 +258,7 @@ int idxd_setup_sysfs(struct idxd_device *idxd);
void idxd_cleanup_sysfs(struct idxd_device *idxd);
int idxd_register_driver(void);
void idxd_unregister_driver(void);
+struct bus_type *idxd_get_bus_type(struct idxd_device *idxd);

/* device interrupt control */
irqreturn_t idxd_irq_handler(int vec, void *data);
@@ -267,4 +297,12 @@ void idxd_unregister_dma_device(struct idxd_device *idxd);
int idxd_register_dma_channel(struct idxd_wq *wq);
void idxd_unregister_dma_channel(struct idxd_wq *wq);
void idxd_parse_completion_status(u8 status, enum dmaengine_tx_result *res);
+
+/* cdev */
+int idxd_cdev_register(void);
+void idxd_cdev_remove(void);
+int idxd_cdev_get_major(struct idxd_device *idxd);
+int idxd_wq_add_cdev(struct idxd_wq *wq);
+void idxd_wq_del_cdev(struct idxd_wq *wq);
+
#endif
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index b2e887508078..b247ef57f5c1 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -188,6 +188,7 @@ static int idxd_setup_internals(struct idxd_device *idxd)
mutex_init(&wq->wq_lock);
atomic_set(&wq->dq_count, 0);
init_waitqueue_head(&wq->submit_waitq);
+ wq->idxd_cdev.minor = -1;
rc = percpu_init_rwsem(&wq->submit_lock);
if (rc < 0) {
idxd_wqs_free_lock(idxd);
@@ -321,6 +322,8 @@ static int idxd_probe(struct idxd_device *idxd)
goto err_idr_fail;
}

+ idxd->major = idxd_cdev_get_major(idxd);
+
dev_dbg(dev, "IDXD device %d probed successfully\n", idxd->id);
return 0;

@@ -519,6 +522,10 @@ static int __init idxd_init_module(void)
if (err < 0)
goto err_idxd_driver_register;

+ err = idxd_cdev_register();
+ if (err)
+ goto err_cdev_register;
+
err = pci_register_driver(&idxd_pci_driver);
if (err)
goto err_pci_register;
@@ -526,6 +533,8 @@ static int __init idxd_init_module(void)
return 0;

err_pci_register:
+ idxd_cdev_remove();
+err_cdev_register:
idxd_unregister_driver();
err_idxd_driver_register:
idxd_unregister_bus_type();
@@ -536,6 +545,7 @@ module_init(idxd_init_module);
static void __exit idxd_exit_module(void)
{
pci_unregister_driver(&idxd_pci_driver);
+ idxd_cdev_remove();
idxd_unregister_bus_type();
}
module_exit(idxd_exit_module);
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index b4adeb2817d1..442f21eeb0fb 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -89,6 +89,24 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
idxd->sw_err.bits[i] = ioread64(idxd->reg_base +
IDXD_SWERR_OFFSET + i * sizeof(u64));
iowrite64(IDXD_SWERR_ACK, idxd->reg_base + IDXD_SWERR_OFFSET);
+
+ if (idxd->sw_err.valid && idxd->sw_err.wq_idx_valid) {
+ int id = idxd->sw_err.wq_idx;
+ struct idxd_wq *wq = &idxd->wqs[id];
+
+ if (wq->type == IDXD_WQT_USER)
+ wake_up_interruptible(&wq->idxd_cdev.err_queue);
+ } else {
+ int i;
+
+ for (i = 0; i < idxd->max_wqs; i++) {
+ struct idxd_wq *wq = &idxd->wqs[i];
+
+ if (wq->type == IDXD_WQT_USER)
+ wake_up_interruptible(&wq->idxd_cdev.err_queue);
+ }
+ }
+
spin_unlock_bh(&idxd->dev_lock);
val |= IDXD_INTC_ERR;

diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index f7baa1bbb0c7..0e6dea34edc9 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -71,17 +71,19 @@ static int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc,
{
struct idxd_device *idxd = wq->idxd;
int vec = desc->hw->int_handle;
+ void __iomem *portal;

if (idxd->state != IDXD_DEV_ENABLED)
return -EIO;

+ portal = wq->dportal + idxd_get_wq_portal_offset(IDXD_PORTAL_UNLIMITED);
/*
* The wmb() flushes writes to coherent DMA data before possibly
* triggering a DMA read. The wmb() is necessary even on UP because
* the recipient is a device.
*/
wmb();
- iosubmit_cmds512(wq->dportal, desc->hw, 1);
+ iosubmit_cmds512(portal, desc->hw, 1);

/*
* Pending the descriptor to the lockless list for the irq_entry
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index bcbd6020c8ee..4d0480ec97f7 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -13,6 +13,7 @@
static char *idxd_wq_type_names[] = {
[IDXD_WQT_NONE] = "none",
[IDXD_WQT_KERNEL] = "kernel",
+ [IDXD_WQT_USER] = "user",
};

static void idxd_conf_device_release(struct device *dev)
@@ -63,6 +64,11 @@ static inline bool is_idxd_wq_dmaengine(struct idxd_wq *wq)
return false;
}

+static inline bool is_idxd_wq_cdev(struct idxd_wq *wq)
+{
+ return wq->type == IDXD_WQT_USER ? true : false;
+}
+
static int idxd_config_bus_match(struct device *dev,
struct device_driver *drv)
{
@@ -109,6 +115,9 @@ static int idxd_config_bus_probe(struct device *dev)
return -EBUSY;
}

+ if (!try_module_get(THIS_MODULE))
+ return -ENXIO;
+
spin_lock_irqsave(&idxd->dev_lock, flags);

/* Perform IDXD configuration and enabling */
@@ -216,6 +225,13 @@ static int idxd_config_bus_probe(struct device *dev)
mutex_unlock(&wq->wq_lock);
return rc;
}
+ } else if (is_idxd_wq_cdev(wq)) {
+ rc = idxd_wq_add_cdev(wq);
+ if (rc < 0) {
+ dev_dbg(dev, "Cdev creation failed\n");
+ mutex_unlock(&wq->wq_lock);
+ return rc;
+ }
}

mutex_unlock(&wq->wq_lock);
@@ -241,6 +257,8 @@ static void disable_wq(struct idxd_wq *wq)

if (is_idxd_wq_dmaengine(wq))
idxd_unregister_dma_channel(wq);
+ else if (is_idxd_wq_cdev(wq))
+ idxd_wq_del_cdev(wq);

if (idxd_wq_refcount(wq))
dev_warn(dev, "Clients has claim on wq %d: %d\n",
@@ -295,10 +313,12 @@ static int idxd_config_bus_remove(struct device *dev)
spin_lock_irqsave(&idxd->dev_lock, flags);
rc = idxd_device_disable(idxd);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
+ module_put(THIS_MODULE);
if (rc < 0)
dev_warn(dev, "Device disable failed\n");
else
dev_info(dev, "Device %s disabled\n", dev_name(dev));
+
}

return 0;
@@ -309,7 +329,7 @@ static void idxd_config_bus_shutdown(struct device *dev)
dev_dbg(dev, "%s called\n", __func__);
}

-static struct bus_type dsa_bus_type = {
+struct bus_type dsa_bus_type = {
.name = "dsa",
.match = idxd_config_bus_match,
.probe = idxd_config_bus_probe,
@@ -334,7 +354,7 @@ static struct idxd_device_driver *idxd_drvs[] = {
&dsa_drv
};

-static struct bus_type *idxd_get_bus_type(struct idxd_device *idxd)
+struct bus_type *idxd_get_bus_type(struct idxd_device *idxd)
{
return idxd_bus_types[idxd->type];
}
@@ -956,6 +976,9 @@ static ssize_t wq_type_show(struct device *dev,
case IDXD_WQT_KERNEL:
return sprintf(buf, "%s\n",
idxd_wq_type_names[IDXD_WQT_KERNEL]);
+ case IDXD_WQT_USER:
+ return sprintf(buf, "%s\n",
+ idxd_wq_type_names[IDXD_WQT_USER]);
case IDXD_WQT_NONE:
default:
return sprintf(buf, "%s\n",
@@ -978,6 +1001,8 @@ static ssize_t wq_type_store(struct device *dev,
old_type = wq->type;
if (sysfs_streq(buf, idxd_wq_type_names[IDXD_WQT_KERNEL]))
wq->type = IDXD_WQT_KERNEL;
+ else if (sysfs_streq(buf, idxd_wq_type_names[IDXD_WQT_USER]))
+ wq->type = IDXD_WQT_USER;
else
wq->type = IDXD_WQT_NONE;

@@ -1020,6 +1045,17 @@ static ssize_t wq_name_store(struct device *dev,
static struct device_attribute dev_attr_wq_name =
__ATTR(name, 0644, wq_name_show, wq_name_store);

+static ssize_t wq_cdev_minor_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev);
+
+ return sprintf(buf, "%d\n", wq->idxd_cdev.minor);
+}
+
+static struct device_attribute dev_attr_wq_cdev_minor =
+ __ATTR(cdev_minor, 0444, wq_cdev_minor_show, NULL);
+
static struct attribute *idxd_wq_attributes[] = {
&dev_attr_wq_clients.attr,
&dev_attr_wq_state.attr,
@@ -1029,6 +1065,7 @@ static struct attribute *idxd_wq_attributes[] = {
&dev_attr_wq_priority.attr,
&dev_attr_wq_type.attr,
&dev_attr_wq_name.attr,
+ &dev_attr_wq_cdev_minor.attr,
NULL,
};

@@ -1242,6 +1279,16 @@ static ssize_t token_limit_store(struct device *dev,
}
static DEVICE_ATTR_RW(token_limit);

+static ssize_t cdev_major_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct idxd_device *idxd =
+ container_of(dev, struct idxd_device, conf_dev);
+
+ return sprintf(buf, "%u\n", idxd->major);
+}
+static DEVICE_ATTR_RO(cdev_major);
+
static struct attribute *idxd_device_attributes[] = {
&dev_attr_max_groups.attr,
&dev_attr_max_work_queues.attr,
@@ -1257,6 +1304,7 @@ static struct attribute *idxd_device_attributes[] = {
&dev_attr_errors.attr,
&dev_attr_max_tokens.attr,
&dev_attr_token_limit.attr,
+ &dev_attr_cdev_major.attr,
NULL,
};