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ptdma: pt_core_execute_cmd() should use spinlock 

The interrupt handler (pt_core_irq_handler()) of the ptdma
driver can be called from interrupt context. The code flow
in this function can lead down to pt_core_execute_cmd() which
will attempt to grab a mutex, which is not appropriate in
interrupt context and ultimately leads to a kernel panic.
The fix here changes this mutex to a spinlock, which has
been verified to resolve the issue.

Fixes: fa5d823b16 ("dmaengine: ptdma: Initial driver for the AMD PTDMA")
Signed-off-by: Eric Pilmore <epilmore@gigaio.com>
Link: https://lore.kernel.org/r/20230119033907.35071-1-epilmore@gigaio.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Eric Pilmore 2023-01-18 19:39:08 -08:00 committed by Vinod Koul
parent a7a7ee6f5a
commit 95e5fda3b5
2 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/dma/ptdma/ptdma-dev.c
View File

@ -71,12 +71,13 @@ static int pt_core_execute_cmd(struct ptdma_desc *desc, struct pt_cmd_queue *cmd
bool soc = FIELD_GET(DWORD0_SOC, desc->dw0);
u8 *q_desc = (u8 *)&cmd_q->qbase[cmd_q->qidx];
u32 tail;
unsigned long flags;
if (soc) {
desc->dw0 |= FIELD_PREP(DWORD0_IOC, desc->dw0);
desc->dw0 &= ~DWORD0_SOC;
}
mutex_lock(&cmd_q->q_mutex);
spin_lock_irqsave(&cmd_q->q_lock, flags);
/* Copy 32-byte command descriptor to hw queue. */
memcpy(q_desc, desc, 32);
@ -91,7 +92,7 @@ static int pt_core_execute_cmd(struct ptdma_desc *desc, struct pt_cmd_queue *cmd
/* Turn the queue back on using our cached control register */
pt_start_queue(cmd_q);
mutex_unlock(&cmd_q->q_mutex);
spin_unlock_irqrestore(&cmd_q->q_lock, flags);
return 0;
}
@ -199,7 +200,7 @@ int pt_core_init(struct pt_device *pt)
cmd_q->pt = pt;
cmd_q->dma_pool = dma_pool;
mutex_init(&cmd_q->q_mutex);
spin_lock_init(&cmd_q->q_lock);
/* Page alignment satisfies our needs for N <= 128 */
cmd_q->qsize = Q_SIZE(Q_DESC_SIZE);

2
drivers/dma/ptdma/ptdma.h
View File

@ -196,7 +196,7 @@ struct pt_cmd_queue {
struct ptdma_desc *qbase;
/* Aligned queue start address (per requirement) */
struct mutex q_mutex ____cacheline_aligned;
spinlock_t q_lock ____cacheline_aligned;
unsigned int qidx;
unsigned int qsize;