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net: cadence: macb: Fix a possible deadlock in macb_halt_tx.

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[ Upstream commit c92d6089d8ad7d4d815ebcedee3f3907b539ff1f ]

There is a situation where after THALT is set high, TGO stays high as
well. Because jiffies are never updated, as we are in a context with
interrupts disabled, we never exit that loop and have a deadlock.

That deadlock was noticed on a sama5d4 device that stayed locked for days.

Use retries instead of jiffies so that the timeout really works and we do
not have a deadlock anymore.

Fixes: e86cd53afc ("net/macb: better manage tx errors")
Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250509121935.16282-1-othacehe@gnu.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Mathieu Othacehe
2025-05-09 14:19:35 +02:00
committed by Greg Kroah-Hartman
parent 4e132f56bc
commit 1d60c0781c
1 changed files with 6 additions and 13 deletions
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19
drivers/net/ethernet/cadence/macb_main.c
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@@ -1016,22 +1016,15 @@ static void macb_update_stats(struct macb *bp)
static int macb_halt_tx(struct macb *bp) static int macb_halt_tx(struct macb *bp)
{ {
unsigned long halt_time, timeout; u32 status;
u32 status;
macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(THALT)); macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(THALT));
timeout = jiffies + usecs_to_jiffies(MACB_HALT_TIMEOUT); /* Poll TSR until TGO is cleared or timeout. */
do { return read_poll_timeout_atomic(macb_readl, status,
halt_time = jiffies; !(status & MACB_BIT(TGO)),
status = macb_readl(bp, TSR); 250, MACB_HALT_TIMEOUT, false,
if (!(status & MACB_BIT(TGO))) bp, TSR);
return 0;
udelay(250);
} while (time_before(halt_time, timeout));
return -ETIMEDOUT;
} }
static void macb_tx_unmap(struct macb *bp, struct macb_tx_skb *tx_skb, int budget) static void macb_tx_unmap(struct macb *bp, struct macb_tx_skb *tx_skb, int budget)