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 00:33:13.000000000 
+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)
--
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