[PATCH] Stop using num_physpages in aacraid

[Matthew Wilcox <matthew@wil.cx>]

The num_physpages variable has an interesting and varied definition
depending on the architecture and various CONFIG options, not to mention
whether memory has been hotplugged or not.  At any rate, it doesn't do
what aacraid is trying to use it for -- to determine whether a dma will
be 64-bit.

This patch removes the aac_scsi_32_64() function altogether, favouring
a failure to initialise over failing every command sent to the device.

The various quirks, options and flags are quite confusing.  I think I've
managed to get it right, but I have no hardware to test with.

My understanding:
	AAC_QUIRK_SCSI_32 means "This card cannot address above 64-bit.
	But it does support the 64-bit format."

	AAC_OPT_SGMAP_HOST64 means "This card MUST do DAC".

The patch below is intended to reflect that understanding.  If I've
misunderstood the old code, or that wasn't what the old code was supposed
to mean then the below patch is wrong.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
index 460d402..95e524a 100644
--- a/drivers/scsi/aacraid/aachba.c
+++ b/drivers/scsi/aacraid/aachba.c
@@ -1199,15 +1199,6 @@ static int aac_scsi_32(struct fib * fib, struct scsi_cmnd * cmd)
 				  (fib_callback) aac_srb_callback, (void *) cmd);
 }
 
-static int aac_scsi_32_64(struct fib * fib, struct scsi_cmnd * cmd)
-{
-	if ((sizeof(dma_addr_t) > 4) &&
-	 (num_physpages > (0xFFFFFFFFULL >> PAGE_SHIFT)) &&
-	 (fib->dev->adapter_info.options & AAC_OPT_SGMAP_HOST64))
-		return FAILED;
-	return aac_scsi_32(fib, cmd);
-}
-
 int aac_get_adapter_info(struct aac_dev* dev)
 {
 	struct fib* fibptr;
@@ -1367,26 +1358,36 @@ int aac_get_adapter_info(struct aac_dev* dev)
 		printk(KERN_INFO "%s%d: Non-DASD support enabled.\n",dev->name, dev->id);
 
 	dev->dac_support = 0;
-	if( (sizeof(dma_addr_t) > 4) && (dev->adapter_info.options & AAC_OPT_SGMAP_HOST64)){
+	if ((sizeof(dma_addr_t) > 4) &&
+	    (dev->adapter_info.options & AAC_OPT_SGMAP_HOST64)) {
 		if (!dev->in_reset)
 			printk(KERN_INFO "%s%d: 64bit support enabled.\n",
 				dev->name, dev->id);
 		dev->dac_support = 1;
 	}
 
-	if(dacmode != -1) {
+	if (dacmode != -1) {
 		dev->dac_support = (dacmode!=0);
 	}
-	if(dev->dac_support != 0) {
+	if (dev->dac_support &&
+	    !(aac_get_driver_ident(dev->cardtype)->quirks &
+							AAC_QUIRK_SCSI_32)) {
 		if (!pci_set_dma_mask(dev->pdev, DMA_64BIT_MASK) &&
-			!pci_set_consistent_dma_mask(dev->pdev, DMA_64BIT_MASK)) {
+		    !pci_set_consistent_dma_mask(dev->pdev, DMA_64BIT_MASK)) {
 			if (!dev->in_reset)
 				printk(KERN_INFO"%s%d: 64 Bit DAC enabled\n",
 					dev->name, dev->id);
 		} else if (!pci_set_dma_mask(dev->pdev, DMA_32BIT_MASK) &&
-			!pci_set_consistent_dma_mask(dev->pdev, DMA_32BIT_MASK)) {
+			   !pci_set_consistent_dma_mask(dev->pdev,
+							DMA_32BIT_MASK)) {
 			printk(KERN_INFO"%s%d: DMA mask set failed, 64 Bit DAC disabled\n",
 				dev->name, dev->id);
+	 		if (dev->adapter_info.options & AAC_OPT_SGMAP_HOST64) {
+				printk(KERN_INFO "%s%d: 64-bit DAC required "
+					"for this host, bailing out\n",
+					dev->name, dev->id);
+				rcode = -ENOMEM;
+			}
 			dev->dac_support = 0;
 		} else {
 			printk(KERN_WARNING"%s%d: No suitable DMA available.\n",
@@ -1398,11 +1399,7 @@ int aac_get_adapter_info(struct aac_dev* dev)
 	 * Deal with configuring for the individualized limits of each packet
 	 * interface.
 	 */
-	dev->a_ops.adapter_scsi = (dev->dac_support)
-	  ? ((aac_get_driver_ident(dev->cardtype)->quirks & AAC_QUIRK_SCSI_32)
-				? aac_scsi_32_64
-				: aac_scsi_64)
-				: aac_scsi_32;
+	dev->a_ops.adapter_scsi = dev->dac_support ? aac_scsi_64 : aac_scsi_32;
 	if (dev->raw_io_interface) {
 		dev->a_ops.adapter_bounds = (dev->raw_io_64)
 					? aac_bounds_64

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."