Commit ad16bc23 authored by Tudor Ambarus's avatar Tudor Ambarus Committed by Vinod Koul
Browse files

dmaengine: at_hdmac: Return err in case the chan is not free at alloc res time 



Having a list of descriptors allocated for the channel at
device_alloc_chan_resources() time is a sign for bad free usage.
Return err and add a debug message in case the channel is not
free from a previous use.

atchan->descs_allocated becomes useless, get rid of it. More,
drop the error message in atc_desc_get() because now it would
introduce an extra if statement. The callers of atc_desc_get()
already print error messages in case the callee fails, no one
is hurt.

Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: default avatarLudovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-3-tudor.ambarus@microchip.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent bbc58394

drivers/dma/at_hdmac.c

+8 −23
Original line number Diff line number Diff line
@@ -146,17 +146,8 @@ static struct at_desc *atc_desc_get(struct at_dma_chan *atchan) 
		"scanned %u descriptors on freelist\n", i);



	/* no more descriptor available in initial pool: create one more */

	if (!ret) {

	if (!ret)

		ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);

		if (ret) {

			spin_lock_irqsave(&atchan->lock, flags);

			atchan->descs_allocated++;

			spin_unlock_irqrestore(&atchan->lock, flags);

		} else {

			dev_err(chan2dev(&atchan->chan_common),

					"not enough descriptors available\n");

		}

	}



	return ret;

}
@@ -1553,6 +1544,11 @@ static int atc_alloc_chan_resources(struct dma_chan *chan) 
		return -EIO;

	}



	if (!list_empty(&atchan->free_list)) {

		dev_dbg(chan2dev(chan), "can't allocate channel resources (channel not freed from a previous use)\n");

		return -EIO;

	}



	cfg = ATC_DEFAULT_CFG;



	atslave = chan->private;
@@ -1568,11 +1564,6 @@ static int atc_alloc_chan_resources(struct dma_chan *chan) 
			cfg = atslave->cfg;

	}



	/* have we already been set up?

	 * reconfigure channel but no need to reallocate descriptors */

	if (!list_empty(&atchan->free_list))

		return atchan->descs_allocated;



	/* Allocate initial pool of descriptors */

	for (i = 0; i < init_nr_desc_per_channel; i++) {

		desc = atc_alloc_descriptor(chan, GFP_KERNEL);
@@ -1584,17 +1575,15 @@ static int atc_alloc_chan_resources(struct dma_chan *chan) 
		list_add_tail(&desc->desc_node, &atchan->free_list);

	}



	atchan->descs_allocated = i;

	dma_cookie_init(chan);



	/* channel parameters */

	channel_writel(atchan, CFG, cfg);



	dev_dbg(chan2dev(chan),

		"alloc_chan_resources: allocated %d descriptors\n",

		atchan->descs_allocated);

		"alloc_chan_resources: allocated %d descriptors\n", i);



	return atchan->descs_allocated;

	return i;

}



/**
@@ -1608,9 +1597,6 @@ static void atc_free_chan_resources(struct dma_chan *chan) 
	struct at_desc		*desc, *_desc;

	LIST_HEAD(list);



	dev_dbg(chan2dev(chan), "free_chan_resources: (descs allocated=%u)\n",

		atchan->descs_allocated);



	/* ASSERT:  channel is idle */

	BUG_ON(!list_empty(&atchan->active_list));

	BUG_ON(!list_empty(&atchan->queue));
@@ -1623,7 +1609,6 @@ static void atc_free_chan_resources(struct dma_chan *chan) 
		dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys);

	}

	list_splice_init(&atchan->free_list, &list);

	atchan->descs_allocated = 0;

	atchan->status = 0;



	/*

drivers/dma/at_hdmac_regs.h

+0 −2
Original line number Diff line number Diff line
@@ -243,7 +243,6 @@ enum atc_status { 
 * @active_list: list of descriptors dmaengine is being running on

 * @queue: list of descriptors ready to be submitted to engine

 * @free_list: list of descriptors usable by the channel

 * @descs_allocated: records the actual size of the descriptor pool

 */

struct at_dma_chan {

	struct dma_chan		chan_common;
@@ -264,7 +263,6 @@ struct at_dma_chan { 
	struct list_head	active_list;

	struct list_head	queue;

	struct list_head	free_list;

	unsigned int		descs_allocated;

};



#define	channel_readl(atchan, name) \

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