Date: Wed, 7 Sep 2005 12:59:32 +1000
From: Anton Blanchard <anton@samba.org>
To: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
       linuxppc64-dev@ozlabs.org, Santiago Leon <santil@us.ibm.com>,
       Linda Xie <lxiep@us.ibm.com>
Subject: Re: [RFC] SCSI target for IBM Power5 LPAR
Message-ID: <20050907025932.GU6945@krispykreme>
References: <20050906212801.GB14057@cs.umn.edu>
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Hi Dave,

> This device driver provides the SCSI target side of the "virtual
> SCSI" on IBM Power5 systems.  The initiator side has been in mainline
> for a while now (drivers/scsi/ibmvscsi/ibmvscsi.c.)  Targets already
> exist for AIX and OS/400.

Good stuff. Got a couple of small suggestions.

+/* Allocate a buffer with a dma_address.  Don't use dma_alloc_coherent
+ * since that uses GFP_ATOMIC internally and we can tollerate a delay
+ */
+static void *alloc_coherent_buffer(struct server_adapter *adapter, size_t size,
+				   dma_addr_t *dma_handle)
+{
+	void *buffer = kmalloc(size, GFP_KERNEL);
+
+	if (buffer) {
+		*dma_handle = dma_map_single(adapter->dev, buffer, size,
+					     DMA_BIDIRECTIONAL);
+
+		if (dma_mapping_error(*dma_handle)) {
+			kfree(buffer);
+			buffer = NULL;
+		}
+	}
+
+	return buffer;
+}

This should be fixed in mainline, on ppc64 we no longer build the dma_*
ops on top of the pci_* ops. This means we actually look at the flags :)

+	adapter->max_sectors = MAX_SECTORS;

Does this mean we are limited to 128kB transfers? Would it be OK to
bump the default?

Anton
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