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dmaengine: sh: rz-dmac: Protect the driver specific lists

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The driver lists (ld_free, ld_queue) are used in
rz_dmac_free_chan_resources(), rz_dmac_terminate_all(),
rz_dmac_issue_pending(), and rz_dmac_irq_handler_thread(), all under
the virtual channel lock. Take the same lock in rz_dmac_prep_slave_sg()
and rz_dmac_prep_dma_memcpy() as well to avoid concurrency issues, since
these functions also check whether the lists are empty and update or
remove list entries.

Fixes: 5000d37042 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Cc: stable@vger.kernel.org
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20260316133252.240348-2-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Claudiu Beznea
2026-03-16 15:32:45 +02:00
committed by Vinod Koul
parent e1c9866173
commit abb863e621
1 changed files with 33 additions and 26 deletions
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59
drivers/dma/sh/rz-dmac.c
View File

@@ -10,6 +10,7 @@
*/
#include <linux/bitfield.h>
#include <linux/cleanup.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
@@ -447,6 +448,7 @@ static int rz_dmac_alloc_chan_resources(struct dma_chan *chan)
if (!desc)
break;
/* No need to lock. This is called only for the 1st client. */
list_add_tail(&desc->node, &channel->ld_free);
channel->descs_allocated++;
}
@@ -502,18 +504,21 @@ rz_dmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
dev_dbg(dmac->dev, "%s channel: %d src=0x%pad dst=0x%pad len=%zu\n",
__func__, channel->index, &src, &dest, len);
if (list_empty(&channel->ld_free))
return NULL;
scoped_guard(spinlock_irqsave, &channel->vc.lock) {
if (list_empty(&channel->ld_free))
return NULL;
desc = list_first_entry(&channel->ld_free, struct rz_dmac_desc, node);
desc = list_first_entry(&channel->ld_free, struct rz_dmac_desc, node);
desc->type = RZ_DMAC_DESC_MEMCPY;
desc->src = src;
desc->dest = dest;
desc->len = len;
desc->direction = DMA_MEM_TO_MEM;
desc->type = RZ_DMAC_DESC_MEMCPY;
desc->src = src;
desc->dest = dest;
desc->len = len;
desc->direction = DMA_MEM_TO_MEM;
list_move_tail(channel->ld_free.next, &channel->ld_queue);
}
list_move_tail(channel->ld_free.next, &channel->ld_queue);
return vchan_tx_prep(&channel->vc, &desc->vd, flags);
}
@@ -529,27 +534,29 @@ rz_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
int dma_length = 0;
int i = 0;
if (list_empty(&channel->ld_free))
return NULL;
scoped_guard(spinlock_irqsave, &channel->vc.lock) {
if (list_empty(&channel->ld_free))
return NULL;
desc = list_first_entry(&channel->ld_free, struct rz_dmac_desc, node);
desc = list_first_entry(&channel->ld_free, struct rz_dmac_desc, node);
for_each_sg(sgl, sg, sg_len, i) {
dma_length += sg_dma_len(sg);
for_each_sg(sgl, sg, sg_len, i)
dma_length += sg_dma_len(sg);
desc->type = RZ_DMAC_DESC_SLAVE_SG;
desc->sg = sgl;
desc->sgcount = sg_len;
desc->len = dma_length;
desc->direction = direction;
if (direction == DMA_DEV_TO_MEM)
desc->src = channel->src_per_address;
else
desc->dest = channel->dst_per_address;
list_move_tail(channel->ld_free.next, &channel->ld_queue);
}
desc->type = RZ_DMAC_DESC_SLAVE_SG;
desc->sg = sgl;
desc->sgcount = sg_len;
desc->len = dma_length;
desc->direction = direction;
if (direction == DMA_DEV_TO_MEM)
desc->src = channel->src_per_address;
else
desc->dest = channel->dst_per_address;
list_move_tail(channel->ld_free.next, &channel->ld_queue);
return vchan_tx_prep(&channel->vc, &desc->vd, flags);
}