Re: [PATCH] a100u2w: fix bitmap lookup routine

[FUJITA Tomonori <tomof@acm.org>]

On Wed, 19 Mar 2008 10:24:19 -0400
Alan Cox <alan@redhat.com> wrote:

> On Mon, Mar 17, 2008 at 09:46:44AM -0500, James Bottomley wrote:
> > On Mon, 2008-03-17 at 21:32 +0900, Akinobu Mita wrote:
> > > This patch is only compile tested.
> > 
> > It looks fine to me ... I don't suppose we can find someone with an
> > actual card to test it out, could we?
> > 
> > Another observation is that this code is really trying to reinvent
> > bitmaps, so if someone with a card cares they could convert it over to
> > the linux bitmap infrastructure.
> 
> If you want it tested then send me the patch.

Can you try this?

Thanks,

diff --git a/drivers/scsi/a100u2w.c b/drivers/scsi/a100u2w.c
index f608d4a..a183dab 100644
--- a/drivers/scsi/a100u2w.c
+++ b/drivers/scsi/a100u2w.c
@@ -664,22 +664,16 @@ static int orc_device_reset(struct orc_host * host, struct scsi_cmnd *cmd, unsig
 
 static struct orc_scb *__orc_alloc_scb(struct orc_host * host)
 {
-	u8 channel;
-	unsigned long idx;
-	u8 index;
-	u8 i;
+	long idx;
+	unsigned size = sizeof(host->allocation_map[host->index]) * 8;
+	unsigned long *map = (unsigned long *)host->allocation_map[host->index];
 
-	channel = host->index;
-	for (i = 0; i < 8; i++) {
-		for (index = 0; index < 32; index++) {
-			if ((host->allocation_map[channel][i] >> index) & 0x01) {
-				host->allocation_map[channel][i] &= ~(1 << index);
-				break;
-			}
-		}
-		idx = index + 32 * i;
+	idx = find_first_bit(map, size);
+	if (idx < size) {
+		clear_bit(idx, map);
 		/* Translate the index to a structure instance */
-		return (struct orc_scb *) ((unsigned long) host->scb_virt + (idx * sizeof(struct orc_scb)));
+		return (struct orc_scb *)((unsigned long) host->scb_virt
+					  + (idx * sizeof(struct orc_scb)));
 	}
 	return NULL;
 }
@@ -715,14 +709,9 @@ static struct orc_scb *orc_alloc_scb(struct orc_host * host)
 static void orc_release_scb(struct orc_host *host, struct orc_scb *scb)
 {
 	unsigned long flags;
-	u8 index, i, channel;
 
 	spin_lock_irqsave(&(host->allocation_lock), flags);
-	channel = host->index;	/* Channel */
-	index = scb->scbidx;
-	i = index / 32;
-	index %= 32;
-	host->allocation_map[channel][i] |= (1 << index);
+	set_bit(scb->scbidx, host->allocation_map[host->index]);
 	spin_unlock_irqrestore(&(host->allocation_lock), flags);
 }