From: Finn Thain <fthain@telegraphics.com.au>
To: David Miller <davem@davemloft.net>
Cc: linux-m68k@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH] mac_esp: remove redundant mutual exclusion
Date: Sun, 11 Sep 2011 01:01:34 +1000 (EST) [thread overview]
Message-ID: <alpine.LNX.2.00.1109110038500.5327@nippy.intranet> (raw)
Mutual exclusion is redundant here because all the paths in the call graph
leading to esp_driver_ops.send_dma_cmd() happen under spin_lock_irqsave/
spin_lock_irqrestore. Remove it.
Tested on a Mac Quadra 660av and a Mac LC 630.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
Part of this patch relates to Geert's m68k generic hard irq conversion
work. Under genirq, the disable_irq() in mac_esp leads to deadlock. It
wasn't a problem before because the m68k disable_irq() implementation is
equivalent to genirq's disable_irq_nosync().
Index: linux-m68k/drivers/scsi/mac_esp.c
===================================================================
--- linux-m68k.orig/drivers/scsi/mac_esp.c 2011-08-28 00:33:13.000000000 +1000
+++ linux-m68k/drivers/scsi/mac_esp.c 2011-08-28 00:35:48.000000000 +1000
@@ -230,9 +230,6 @@ static void mac_esp_send_pdma_cmd(struct
u32 dma_count, int write, u8 cmd)
{
struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
- unsigned long flags;
-
- local_irq_save(flags);
mep->error = 0;
@@ -270,8 +267,6 @@ static void mac_esp_send_pdma_cmd(struct
esp_count = n;
}
} while (esp_count);
-
- local_irq_restore(flags);
}
/*
@@ -353,8 +348,6 @@ static void mac_esp_send_pio_cmd(struct
struct mac_esp_priv *mep = MAC_ESP_GET_PRIV(esp);
u8 *fifo = esp->regs + ESP_FDATA * 16;
- disable_irq(esp->host->irq);
-
cmd &= ~ESP_CMD_DMA;
mep->error = 0;
@@ -431,8 +424,6 @@ static void mac_esp_send_pio_cmd(struct
scsi_esp_cmd(esp, ESP_CMD_TI);
}
}
-
- enable_irq(esp->host->irq);
}
static int mac_esp_irq_pending(struct esp *esp)
next reply other threads:[~2011-09-10 15:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-10 15:01 Finn Thain [this message]
2011-09-10 18:28 ` [PATCH] mac_esp: remove redundant mutual exclusion David Miller
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