[PATCH] mac_esp: remove redundant mutual exclusion
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 fth...@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().
I initially sent this to the wrong list by mistake... this is the same
patch.
Index: linux-m68k/drivers/scsi/mac_esp.c
===
--- linux-m68k.orig/drivers/scsi/mac_esp.c 2011-08-28 00:33:13.0
+1000
+++ linux-m68k/drivers/scsi/mac_esp.c 2011-08-28 00:35:48.0 +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)
--
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[PATCH] mac_esp: remove redundant mutual exclusion
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 fth...@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 00:33:13.0
+1000
+++ linux-m68k/drivers/scsi/mac_esp.c 2011-08-28 00:35:48.0 +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)
--
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Re: [PATCH] mac_esp: remove redundant mutual exclusion
From: Finn Thain fth...@telegraphics.com.au Date: Sun, 11 Sep 2011 01:01:34 +1000 (EST) 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 fth...@telegraphics.com.au This patch should be CC:'d to linux-scsi not netdev I understand how the networking maintainer is very responsive and the SCSI maintainer generally takes forever, so your Freudian slip will go unjudged :-) -- To unsubscribe from this list: send the line unsubscribe linux-m68k in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
