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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: Tudor Ambarus <tudor.ambarus@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200123140237.125799-3-tudor.ambarus@microchip.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
alistair/sensors
Tudor Ambarus 2020-01-23 14:03:06 +00:00 committed by Vinod Koul
parent bbc58394d8
commit ad16bc232d
2 changed files with 8 additions and 25 deletions
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31
drivers/dma/at_hdmac.c
View File

@ -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;
/*

2
drivers/dma/at_hdmac_regs.h
View File

@ -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) \