dmaengine: idxd: add support for configurable max wq xfer size

Add sysfs attribute max_xfer_size to wq in order to allow the max xfer
size configured on a per wq basis. Add support code to configure
the valid user input on wq enable. This is a performance tuning
parameter.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/159865265404.29141.3049399618578194052.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/Documentation/ABI/stable/sysfs-driver-dma-idxd b/Documentation/ABI/stable/sysfs-driver-dma-idxd
index 1af9c41..452f353 100644 (file)
--- a/Documentation/ABI/stable/sysfs-driver-dma-idxd
+++ b/Documentation/ABI/stable/sysfs-driver-dma-idxd
@@ -170,6 +170,13 @@ Contact:        dmaengine@vger.kernel.org
 Description:    The number of entries in this work queue that may be filled
                via a limited portal.
 
+What:          /sys/bus/dsa/devices/wq<m>.<n>/max_transfer_size
+Date:          Aug 28, 2020
+KernelVersion: 5.10.0
+Contact:       dmaengine@vger.kernel.org
+Description:   The max transfer sized for this workqueue. Cannot exceed device
+               max transfer size. Configurable parameter.
+
 What:           /sys/bus/dsa/devices/engine<m>.<n>/group_id
 Date:           Oct 25, 2019
 KernelVersion:  5.6.0

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 14b4585..b8dbb70 100644 (file)
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -529,7 +529,7 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
        wq->wqcfg.priority = wq->priority;
 
        /* bytes 12-15 */
-       wq->wqcfg.max_xfer_shift = idxd->hw.gen_cap.max_xfer_shift;
+       wq->wqcfg.max_xfer_shift = ilog2(wq->max_xfer_bytes);
        wq->wqcfg.max_batch_shift = idxd->hw.gen_cap.max_batch_shift;
 
        dev_dbg(dev, "WQ %d CFGs\n", wq->id);

diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index e62b479..81db2a4 100644 (file)
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -114,6 +114,7 @@ struct idxd_wq {
        struct sbitmap_queue sbq;
        struct dma_chan dma_chan;
        char name[WQ_NAME_SIZE + 1];
+       u64 max_xfer_bytes;
 };
 
 struct idxd_engine {

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index c7c6197..e5ed575 100644 (file)
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -176,6 +176,7 @@ static int idxd_setup_internals(struct idxd_device *idxd)
                wq->idxd = idxd;
                mutex_init(&wq->wq_lock);
                wq->idxd_cdev.minor = -1;
+               wq->max_xfer_bytes = idxd->max_xfer_bytes;
        }
 
        for (i = 0; i < idxd->max_engines; i++) {

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index dcba609..a3bac72 100644 (file)
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -1064,6 +1064,45 @@ static ssize_t wq_cdev_minor_show(struct device *dev,
 static struct device_attribute dev_attr_wq_cdev_minor =
                __ATTR(cdev_minor, 0444, wq_cdev_minor_show, NULL);
 
+static ssize_t wq_max_transfer_size_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, "%llu\n", wq->max_xfer_bytes);
+}
+
+static ssize_t wq_max_transfer_size_store(struct device *dev, struct device_attribute *attr,
+                                         const char *buf, size_t count)
+{
+       struct idxd_wq *wq = container_of(dev, struct idxd_wq, conf_dev);
+       struct idxd_device *idxd = wq->idxd;
+       u64 xfer_size;
+       int rc;
+
+       if (wq->state != IDXD_WQ_DISABLED)
+               return -EPERM;
+
+       rc = kstrtou64(buf, 0, &xfer_size);
+       if (rc < 0)
+               return -EINVAL;
+
+       if (xfer_size == 0)
+               return -EINVAL;
+
+       xfer_size = roundup_pow_of_two(xfer_size);
+       if (xfer_size > idxd->max_xfer_bytes)
+               return -EINVAL;
+
+       wq->max_xfer_bytes = xfer_size;
+
+       return count;
+}
+
+static struct device_attribute dev_attr_wq_max_transfer_size =
+               __ATTR(max_transfer_size, 0644,
+                      wq_max_transfer_size_show, wq_max_transfer_size_store);
+
 static struct attribute *idxd_wq_attributes[] = {
        &dev_attr_wq_clients.attr,
        &dev_attr_wq_state.attr,
@@ -1074,6 +1113,7 @@ static struct attribute *idxd_wq_attributes[] = {
        &dev_attr_wq_type.attr,
        &dev_attr_wq_name.attr,
        &dev_attr_wq_cdev_minor.attr,
+       &dev_attr_wq_max_transfer_size.attr,
        NULL,
 };