This is the refined version based upon the guidance of Joe, and is safer.
Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>
---
--- a/drivers/scsi/scsi_tgt_if.c 2010-11-01 19:54:12.000000000 +0800
+++ b/drivers/scsi/scsi_tgt_if.c 2010-11-16 22:10:20.000000000 +0800
@@ -84,7 +84,7 @@ static int tgt_uspace_send_event(u32 typ
if (!ev->hdr.status)
tgt_ring_idx_inc(ring);
else
- err = -BUSY;
+ err = -EBUSY;
spin_unlock_irqrestore(&ring->tr_lock, flags);
@@ -318,9 +318,31 @@ static int tgt_mmap(struct file *filp, s
return err;
}
+static unsigned long tgt_busy = 0;
+
static int tgt_open(struct inode *inode, struct file *file)
{
- tx_ring.tr_idx = rx_ring.tr_idx = 0;
+ int err = -EBUSY;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tx_ring.tr_lock, flags);
+ if (! tgt_busy) {
+ tgt_busy++;
+ tx_ring.tr_idx = rx_ring.tr_idx = 0;
+ err = 0;
+ }
+ spin_unlock_irqrestore(&tx_ring.tr_lock, flags);
+
+ return err;
+}
+
+static int tgt_release(struct inode *inode, struct file *file)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&tx_ring.tr_lock, flags);
+ tgt_busy = 0;
+ spin_unlock_irqrestore(&tx_ring.tr_lock, flags);
return 0;
}
@@ -332,6 +354,7 @@ static const struct file_operations tgt_
.write = tgt_write,
.mmap = tgt_mmap,
.llseek = noop_llseek,
+ .release = tgt_release,
};
static struct miscdevice tgt_miscdev = {
--
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