From: <Tudor.Ambarus@microchip.com>
To: <Ludovic.Desroches@microchip.com>, <dan.j.williams@intel.com>,
<vkoul@kernel.org>
Cc: <dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<Tudor.Ambarus@microchip.com>
Subject: [PATCH 03/10] dmaengine: at_hdmac: Return err in case the chan is not free at alloc res time
Date: Thu, 23 Jan 2020 14:03:06 +0000 [thread overview]
Message-ID: <20200123140237.125799-3-tudor.ambarus@microchip.com> (raw)
In-Reply-To: <20200123140237.125799-1-tudor.ambarus@microchip.com>
From: Tudor Ambarus <tudor.ambarus@microchip.com>
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>
---
drivers/dma/at_hdmac.c | 31 ++++++++-----------------------
drivers/dma/at_hdmac_regs.h | 2 --
2 files changed, 8 insertions(+), 25 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 301bae45cf8d..e17b75075904 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -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;
/*
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index fe8a5853ec49..397692e937b3 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -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) \
--
2.23.0
next prev parent reply other threads:[~2020-01-23 14:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 14:03 [PATCH 01/10] dmaengine: at_hdmac: Substitute kzalloc with kmalloc Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 02/10] dmaengine: at_hdmac: Drop locking in at_hdmac_alloc_chan_resources() Tudor.Ambarus
2020-01-23 14:03 ` Tudor.Ambarus [this message]
2020-01-23 14:03 ` [PATCH 04/10] dmaengine: at_hdmac: Drop description for a not defined parameter Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 05/10] dmaengine: at_hdmac: Switch atomic allocations to GFP_NOWAIT Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 06/10] dmaengine: at_hdmac: Fix deadlocks Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 07/10] dmaengine: at_xdmac: Drop always true check Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 08/10] dmaengine: at_xdmac: Drop locking in at_xdmac_alloc_chan_resources() Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 09/10] dmaengine: at_xdmac: GFP_KERNEL for user that can sleep Tudor.Ambarus
2020-01-23 14:03 ` [PATCH 10/10] dmaengine: at_xdmac: Fix locking in tasklet Tudor.Ambarus
2020-02-03 8:24 ` [PATCH 01/10] dmaengine: at_hdmac: Substitute kzalloc with kmalloc Ludovic Desroches
2020-02-25 5:58 ` Vinod Koul
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