From 20d60f6364474a978ab2a2146fb4c2bd9b6bbe3f Mon Sep 17 00:00:00 2001 From: Maciej Grochowski Date: Tue, 14 Apr 2020 00:17:03 -0400 Subject: include/linux/dmaengine: Typos fixes in API documentation Signed-off-by: Maciej Grochowski Link: https://lore.kernel.org/r/20200414041703.6661-1-maciek.grochowski@gmail.com Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 21065c04c4ac..31e58ec9f741 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -83,9 +83,9 @@ enum dma_transfer_direction { /** * Interleaved Transfer Request * ---------------------------- - * A chunk is collection of contiguous bytes to be transfered. + * A chunk is collection of contiguous bytes to be transferred. * The gap(in bytes) between two chunks is called inter-chunk-gap(ICG). - * ICGs may or maynot change between chunks. + * ICGs may or may not change between chunks. * A FRAME is the smallest series of contiguous {chunk,icg} pairs, * that when repeated an integral number of times, specifies the transfer. * A transfer template is specification of a Frame, the number of times @@ -1069,7 +1069,7 @@ static inline int dmaengine_terminate_all(struct dma_chan *chan) * dmaengine_synchronize() needs to be called before it is safe to free * any memory that is accessed by previously submitted descriptors or before * freeing any resources accessed from within the completion callback of any - * perviously submitted descriptors. + * previously submitted descriptors. * * This function can be called from atomic context as well as from within a * complete callback of a descriptor submitted on the same channel. @@ -1091,7 +1091,7 @@ static inline int dmaengine_terminate_async(struct dma_chan *chan) * * Synchronizes to the DMA channel termination to the current context. When this * function returns it is guaranteed that all transfers for previously issued - * descriptors have stopped and and it is safe to free the memory assoicated + * descriptors have stopped and it is safe to free the memory associated * with them. Furthermore it is guaranteed that all complete callback functions * for a previously submitted descriptor have finished running and it is safe to * free resources accessed from within the complete callbacks. -- cgit v1.2.3 From 0821009445a8261ac4d32a6df4b83938e007c765 Mon Sep 17 00:00:00 2001 From: Dave Jiang Date: Mon, 13 Apr 2020 10:40:12 -0700 Subject: dmaengine: fix channel index enumeration When the channel register code was changed to allow hotplug operations, dynamic indexing wasn't taken into account. When channels are randomly plugged and unplugged out of order, the serial indexing breaks. Convert channel indexing to using IDA tracking in order to allow dynamic assignment. The previous code does not cause any regression bug for existing channel allocation besides idxd driver since the hotplug usage case is only used by idxd at this point. With this change, the chan->idr_ref is also not needed any longer. We can have a device with no channels registered due to hot plug. The channel device release code no longer should attempt to free the dma device id on the last channel release. Fixes: e81274cd6b52 ("dmaengine: add support to dynamic register/unregister of channels") Reported-by: Yixin Zhang Signed-off-by: Dave Jiang Tested-by: Yixin Zhang Link: https://lore.kernel.org/r/158679961260.7674.8485924270472851852.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Vinod Koul --- drivers/dma/dmaengine.c | 60 ++++++++++++++++++++--------------------------- include/linux/dmaengine.h | 4 ++-- 2 files changed, 28 insertions(+), 36 deletions(-) (limited to 'include') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 4830ba658ce1..d31076d9ef25 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -232,10 +232,6 @@ static void chan_dev_release(struct device *dev) struct dma_chan_dev *chan_dev; chan_dev = container_of(dev, typeof(*chan_dev), device); - if (atomic_dec_and_test(chan_dev->idr_ref)) { - ida_free(&dma_ida, chan_dev->dev_id); - kfree(chan_dev->idr_ref); - } kfree(chan_dev); } @@ -1043,27 +1039,9 @@ static int get_dma_id(struct dma_device *device) } static int __dma_async_device_channel_register(struct dma_device *device, - struct dma_chan *chan, - int chan_id) + struct dma_chan *chan) { int rc = 0; - int chancnt = device->chancnt; - atomic_t *idr_ref; - struct dma_chan *tchan; - - tchan = list_first_entry_or_null(&device->channels, - struct dma_chan, device_node); - if (!tchan) - return -ENODEV; - - if (tchan->dev) { - idr_ref = tchan->dev->idr_ref; - } else { - idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL); - if (!idr_ref) - return -ENOMEM; - atomic_set(idr_ref, 0); - } chan->local = alloc_percpu(typeof(*chan->local)); if (!chan->local) @@ -1079,29 +1057,36 @@ static int __dma_async_device_channel_register(struct dma_device *device, * When the chan_id is a negative value, we are dynamically adding * the channel. Otherwise we are static enumerating. */ - chan->chan_id = chan_id < 0 ? chancnt : chan_id; + mutex_lock(&device->chan_mutex); + chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL); + mutex_unlock(&device->chan_mutex); + if (chan->chan_id < 0) { + pr_err("%s: unable to alloc ida for chan: %d\n", + __func__, chan->chan_id); + goto err_out; + } + chan->dev->device.class = &dma_devclass; chan->dev->device.parent = device->dev; chan->dev->chan = chan; - chan->dev->idr_ref = idr_ref; chan->dev->dev_id = device->dev_id; - atomic_inc(idr_ref); dev_set_name(&chan->dev->device, "dma%dchan%d", device->dev_id, chan->chan_id); - rc = device_register(&chan->dev->device); if (rc) - goto err_out; + goto err_out_ida; chan->client_count = 0; - device->chancnt = chan->chan_id + 1; + device->chancnt++; return 0; + err_out_ida: + mutex_lock(&device->chan_mutex); + ida_free(&device->chan_ida, chan->chan_id); + mutex_unlock(&device->chan_mutex); err_out: free_percpu(chan->local); kfree(chan->dev); - if (atomic_dec_return(idr_ref) == 0) - kfree(idr_ref); return rc; } @@ -1110,7 +1095,7 @@ int dma_async_device_channel_register(struct dma_device *device, { int rc; - rc = __dma_async_device_channel_register(device, chan, -1); + rc = __dma_async_device_channel_register(device, chan); if (rc < 0) return rc; @@ -1130,6 +1115,9 @@ static void __dma_async_device_channel_unregister(struct dma_device *device, device->chancnt--; chan->dev->chan = NULL; mutex_unlock(&dma_list_mutex); + mutex_lock(&device->chan_mutex); + ida_free(&device->chan_ida, chan->chan_id); + mutex_unlock(&device->chan_mutex); device_unregister(&chan->dev->device); free_percpu(chan->local); } @@ -1152,7 +1140,7 @@ EXPORT_SYMBOL_GPL(dma_async_device_channel_unregister); */ int dma_async_device_register(struct dma_device *device) { - int rc, i = 0; + int rc; struct dma_chan* chan; if (!device) @@ -1257,9 +1245,12 @@ int dma_async_device_register(struct dma_device *device) if (rc != 0) return rc; + mutex_init(&device->chan_mutex); + ida_init(&device->chan_ida); + /* represent channels in sysfs. Probably want devs too */ list_for_each_entry(chan, &device->channels, device_node) { - rc = __dma_async_device_channel_register(device, chan, i++); + rc = __dma_async_device_channel_register(device, chan); if (rc < 0) goto err_out; } @@ -1334,6 +1325,7 @@ void dma_async_device_unregister(struct dma_device *device) */ dma_cap_set(DMA_PRIVATE, device->cap_mask); dma_channel_rebalance(); + ida_free(&dma_ida, device->dev_id); dma_device_put(device); mutex_unlock(&dma_list_mutex); } diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 31e58ec9f741..e1c03339918f 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -341,13 +341,11 @@ struct dma_chan { * @chan: driver channel device * @device: sysfs device * @dev_id: parent dma_device dev_id - * @idr_ref: reference count to gate release of dma_device dev_id */ struct dma_chan_dev { struct dma_chan *chan; struct device device; int dev_id; - atomic_t *idr_ref; }; /** @@ -835,6 +833,8 @@ struct dma_device { int dev_id; struct device *dev; struct module *owner; + struct ida chan_ida; + struct mutex chan_mutex; /* to protect chan_ida */ u32 src_addr_widths; u32 dst_addr_widths; -- cgit v1.2.3