[SCSI] vmw_pvscsi: SCSI driver for VMware's virtual HBA.

This is a driver for VMware's paravirtualized SCSI device,
which should improve disk performance for guests running
under control of VMware hypervisors that support such devices.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 1407 insertions, 0 deletions

diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c
new file mode 100644
index 00000000000..d2604c813a2
--- /dev/null
+++ b/drivers/scsi/vmw_pvscsi.c
@@ -0,0 +1,1407 @@
+/*
+ * Linux driver for VMware's para-virtualized SCSI HBA.
+ *
+ * Copyright (C) 2008-2009, VMware, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Maintained by: Alok N Kataria <akataria@vmware.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/pci.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+
+#include "vmw_pvscsi.h"
+
+#define PVSCSI_LINUX_DRIVER_DESC "VMware PVSCSI driver"
+
+MODULE_DESCRIPTION(PVSCSI_LINUX_DRIVER_DESC);
+MODULE_AUTHOR("VMware, Inc.");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(PVSCSI_DRIVER_VERSION_STRING);
+
+#define PVSCSI_DEFAULT_NUM_PAGES_PER_RING	8
+#define PVSCSI_DEFAULT_NUM_PAGES_MSG_RING	1
+#define PVSCSI_DEFAULT_QUEUE_DEPTH		64
+#define SGL_SIZE				PAGE_SIZE
+
+struct pvscsi_sg_list {
+	struct PVSCSISGElement sge[PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT];
+};
+
+struct pvscsi_ctx {
+	/*
+	 * The index of the context in cmd_map serves as the context ID for a
+	 * 1-to-1 mapping completions back to requests.
+	 */
+	struct scsi_cmnd	*cmd;
+	struct pvscsi_sg_list	*sgl;
+	struct list_head	list;
+	dma_addr_t		dataPA;
+	dma_addr_t		sensePA;
+	dma_addr_t		sglPA;
+};
+
+struct pvscsi_adapter {
+	char				*mmioBase;
+	unsigned int			irq;
+	u8				rev;
+	bool				use_msi;
+	bool				use_msix;
+	bool				use_msg;
+
+	spinlock_t			hw_lock;
+
+	struct workqueue_struct		*workqueue;
+	struct work_struct		work;
+
+	struct PVSCSIRingReqDesc	*req_ring;
+	unsigned			req_pages;
+	unsigned			req_depth;
+	dma_addr_t			reqRingPA;
+
+	struct PVSCSIRingCmpDesc	*cmp_ring;
+	unsigned			cmp_pages;
+	dma_addr_t			cmpRingPA;
+
+	struct PVSCSIRingMsgDesc	*msg_ring;
+	unsigned			msg_pages;
+	dma_addr_t			msgRingPA;
+
+	struct PVSCSIRingsState		*rings_state;
+	dma_addr_t			ringStatePA;
+
+	struct pci_dev			*dev;
+	struct Scsi_Host		*host;
+
+	struct list_head		cmd_pool;
+	struct pvscsi_ctx		*cmd_map;
+};
+
+
+/* Command line parameters */
+static int pvscsi_ring_pages     = PVSCSI_DEFAULT_NUM_PAGES_PER_RING;
+static int pvscsi_msg_ring_pages = PVSCSI_DEFAULT_NUM_PAGES_MSG_RING;
+static int pvscsi_cmd_per_lun    = PVSCSI_DEFAULT_QUEUE_DEPTH;
+static bool pvscsi_disable_msi;
+static bool pvscsi_disable_msix;
+static bool pvscsi_use_msg       = true;
+
+#define PVSCSI_RW (S_IRUSR | S_IWUSR)
+
+module_param_named(ring_pages, pvscsi_ring_pages, int, PVSCSI_RW);
+MODULE_PARM_DESC(ring_pages, "Number of pages per req/cmp ring - (default="
+		 __stringify(PVSCSI_DEFAULT_NUM_PAGES_PER_RING) ")");
+
+module_param_named(msg_ring_pages, pvscsi_msg_ring_pages, int, PVSCSI_RW);
+MODULE_PARM_DESC(msg_ring_pages, "Number of pages for the msg ring - (default="
+		 __stringify(PVSCSI_DEFAULT_NUM_PAGES_MSG_RING) ")");
+
+module_param_named(cmd_per_lun, pvscsi_cmd_per_lun, int, PVSCSI_RW);
+MODULE_PARM_DESC(cmd_per_lun, "Maximum commands per lun - (default="
+		 __stringify(PVSCSI_MAX_REQ_QUEUE_DEPTH) ")");
+
+module_param_named(disable_msi, pvscsi_disable_msi, bool, PVSCSI_RW);
+MODULE_PARM_DESC(disable_msi, "Disable MSI use in driver - (default=0)");
+
+module_param_named(disable_msix, pvscsi_disable_msix, bool, PVSCSI_RW);
+MODULE_PARM_DESC(disable_msix, "Disable MSI-X use in driver - (default=0)");
+
+module_param_named(use_msg, pvscsi_use_msg, bool, PVSCSI_RW);
+MODULE_PARM_DESC(use_msg, "Use msg ring when available - (default=1)");
+
+static const struct pci_device_id pvscsi_pci_tbl[] = {
+	{ PCI_VDEVICE(VMWARE, PCI_DEVICE_ID_VMWARE_PVSCSI) },
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(pci, pvscsi_pci_tbl);
+
+static struct device *
+pvscsi_dev(const struct pvscsi_adapter *adapter)
+{
+	return &(adapter->dev->dev);
+}
+
+static struct pvscsi_ctx *
+pvscsi_find_context(const struct pvscsi_adapter *adapter, struct scsi_cmnd *cmd)
+{
+	struct pvscsi_ctx *ctx, *end;
+
+	end = &adapter->cmd_map[adapter->req_depth];
+	for (ctx = adapter->cmd_map; ctx < end; ctx++)
+		if (ctx->cmd == cmd)
+			return ctx;
+
+	return NULL;
+}
+
+static struct pvscsi_ctx *
+pvscsi_acquire_context(struct pvscsi_adapter *adapter, struct scsi_cmnd *cmd)
+{
+	struct pvscsi_ctx *ctx;
+
+	if (list_empty(&adapter->cmd_pool))
+		return NULL;
+
+	ctx = list_first_entry(&adapter->cmd_pool, struct pvscsi_ctx, list);
+	ctx->cmd = cmd;
+	list_del(&ctx->list);
+
+	return ctx;
+}
+
+static void pvscsi_release_context(struct pvscsi_adapter *adapter,
+				   struct pvscsi_ctx *ctx)
+{
+	ctx->cmd = NULL;
+	list_add(&ctx->list, &adapter->cmd_pool);
+}
+
+/*
+ * Map a pvscsi_ctx struct to a context ID field value; we map to a simple
+ * non-zero integer. ctx always points to an entry in cmd_map array, hence
+ * the return value is always >=1.
+ */
+static u64 pvscsi_map_context(const struct pvscsi_adapter *adapter,
+			      const struct pvscsi_ctx *ctx)
+{
+	return ctx - adapter->cmd_map + 1;
+}
+
+static struct pvscsi_ctx *
+pvscsi_get_context(const struct pvscsi_adapter *adapter, u64 context)
+{
+	return &adapter->cmd_map[context - 1];
+}
+
+static void pvscsi_reg_write(const struct pvscsi_adapter *adapter,
+			     u32 offset, u32 val)
+{
+	writel(val, adapter->mmioBase + offset);
+}
+
+static u32 pvscsi_reg_read(const struct pvscsi_adapter *adapter, u32 offset)
+{
+	return readl(adapter->mmioBase + offset);
+}
+
+static u32 pvscsi_read_intr_status(const struct pvscsi_adapter *adapter)
+{
+	return pvscsi_reg_read(adapter, PVSCSI_REG_OFFSET_INTR_STATUS);
+}
+
+static void pvscsi_write_intr_status(const struct pvscsi_adapter *adapter,
+				     u32 val)
+{
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_STATUS, val);
+}
+
+static void pvscsi_unmask_intr(const struct pvscsi_adapter *adapter)
+{
+	u32 intr_bits;
+
+	intr_bits = PVSCSI_INTR_CMPL_MASK;
+	if (adapter->use_msg)
+		intr_bits |= PVSCSI_INTR_MSG_MASK;
+
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_MASK, intr_bits);
+}
+
+static void pvscsi_mask_intr(const struct pvscsi_adapter *adapter)
+{
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_INTR_MASK, 0);
+}
+
+static void pvscsi_write_cmd_desc(const struct pvscsi_adapter *adapter,
+				  u32 cmd, const void *desc, size_t len)
+{
+	const u32 *ptr = desc;
+	size_t i;
+
+	len /= sizeof(*ptr);
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_COMMAND, cmd);
+	for (i = 0; i < len; i++)
+		pvscsi_reg_write(adapter,
+				 PVSCSI_REG_OFFSET_COMMAND_DATA, ptr[i]);
+}
+
+static void pvscsi_abort_cmd(const struct pvscsi_adapter *adapter,
+			     const struct pvscsi_ctx *ctx)
+{
+	struct PVSCSICmdDescAbortCmd cmd = { 0 };
+
+	cmd.target = ctx->cmd->device->id;
+	cmd.context = pvscsi_map_context(adapter, ctx);
+
+	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_ABORT_CMD, &cmd, sizeof(cmd));
+}
+
+static void pvscsi_kick_rw_io(const struct pvscsi_adapter *adapter)
+{
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_KICK_RW_IO, 0);
+}
+
+static void pvscsi_process_request_ring(const struct pvscsi_adapter *adapter)
+{
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_KICK_NON_RW_IO, 0);
+}
+
+static int scsi_is_rw(unsigned char op)
+{
+	return op == READ_6  || op == WRITE_6 ||
+	       op == READ_10 || op == WRITE_10 ||
+	       op == READ_12 || op == WRITE_12 ||
+	       op == READ_16 || op == WRITE_16;
+}
+
+static void pvscsi_kick_io(const struct pvscsi_adapter *adapter,
+			   unsigned char op)
+{
+	if (scsi_is_rw(op))
+		pvscsi_kick_rw_io(adapter);
+	else
+		pvscsi_process_request_ring(adapter);
+}
+
+static void ll_adapter_reset(const struct pvscsi_adapter *adapter)
+{
+	dev_dbg(pvscsi_dev(adapter), "Adapter Reset on %p\n", adapter);
+
+	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_ADAPTER_RESET, NULL, 0);
+}
+
+static void ll_bus_reset(const struct pvscsi_adapter *adapter)
+{
+	dev_dbg(pvscsi_dev(adapter), "Reseting bus on %p\n", adapter);
+
+	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_RESET_BUS, NULL, 0);
+}
+
+static void ll_device_reset(const struct pvscsi_adapter *adapter, u32 target)
+{
+	struct PVSCSICmdDescResetDevice cmd = { 0 };
+
+	dev_dbg(pvscsi_dev(adapter), "Reseting device: target=%u\n", target);
+
+	cmd.target = target;
+
+	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_RESET_DEVICE,
+			      &cmd, sizeof(cmd));
+}
+
+static void pvscsi_create_sg(struct pvscsi_ctx *ctx,
+			     struct scatterlist *sg, unsigned count)
+{
+	unsigned i;
+	struct PVSCSISGElement *sge;
+
+	BUG_ON(count > PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT);
+
+	sge = &ctx->sgl->sge[0];
+	for (i = 0; i < count; i++, sg++) {
+		sge[i].addr   = sg_dma_address(sg);
+		sge[i].length = sg_dma_len(sg);
+		sge[i].flags  = 0;
+	}
+}
+
+/*
+ * Map all data buffers for a command into PCI space and
+ * setup the scatter/gather list if needed.
+ */
+static void pvscsi_map_buffers(struct pvscsi_adapter *adapter,
+			       struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd,
+			       struct PVSCSIRingReqDesc *e)
+{
+	unsigned count;
+	unsigned bufflen = scsi_bufflen(cmd);
+	struct scatterlist *sg;
+
+	e->dataLen = bufflen;
+	e->dataAddr = 0;
+	if (bufflen == 0)
+		return;
+
+	sg = scsi_sglist(cmd);
+	count = scsi_sg_count(cmd);
+	if (count != 0) {
+		int segs = scsi_dma_map(cmd);
+		if (segs > 1) {
+			pvscsi_create_sg(ctx, sg, segs);
+
+			e->flags |= PVSCSI_FLAG_CMD_WITH_SG_LIST;
+			ctx->sglPA = pci_map_single(adapter->dev, ctx->sgl,
+						    SGL_SIZE, PCI_DMA_TODEVICE);
+			e->dataAddr = ctx->sglPA;
+		} else
+			e->dataAddr = sg_dma_address(sg);
+	} else {
+		/*
+		 * In case there is no S/G list, scsi_sglist points
+		 * directly to the buffer.
+		 */
+		ctx->dataPA = pci_map_single(adapter->dev, sg, bufflen,
+					     cmd->sc_data_direction);
+		e->dataAddr = ctx->dataPA;
+	}
+}
+
+static void pvscsi_unmap_buffers(const struct pvscsi_adapter *adapter,
+				 struct pvscsi_ctx *ctx)
+{
+	struct scsi_cmnd *cmd;
+	unsigned bufflen;
+
+	cmd = ctx->cmd;
+	bufflen = scsi_bufflen(cmd);
+
+	if (bufflen != 0) {
+		unsigned count = scsi_sg_count(cmd);
+
+		if (count != 0) {
+			scsi_dma_unmap(cmd);
+			if (ctx->sglPA) {
+				pci_unmap_single(adapter->dev, ctx->sglPA,
+						 SGL_SIZE, PCI_DMA_TODEVICE);
+				ctx->sglPA = 0;
+			}
+		} else
+			pci_unmap_single(adapter->dev, ctx->dataPA, bufflen,
+					 cmd->sc_data_direction);
+	}
+	if (cmd->sense_buffer)
+		pci_unmap_single(adapter->dev, ctx->sensePA,
+				 SCSI_SENSE_BUFFERSIZE, PCI_DMA_FROMDEVICE);
+}
+
+static int __devinit pvscsi_allocate_rings(struct pvscsi_adapter *adapter)
+{
+	adapter->rings_state = pci_alloc_consistent(adapter->dev, PAGE_SIZE,
+						    &adapter->ringStatePA);
+	if (!adapter->rings_state)
+		return -ENOMEM;
+
+	adapter->req_pages = min(PVSCSI_MAX_NUM_PAGES_REQ_RING,
+				 pvscsi_ring_pages);
+	adapter->req_depth = adapter->req_pages
+					* PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
+	adapter->req_ring = pci_alloc_consistent(adapter->dev,
+						 adapter->req_pages * PAGE_SIZE,
+						 &adapter->reqRingPA);
+	if (!adapter->req_ring)
+		return -ENOMEM;
+
+	adapter->cmp_pages = min(PVSCSI_MAX_NUM_PAGES_CMP_RING,
+				 pvscsi_ring_pages);
+	adapter->cmp_ring = pci_alloc_consistent(adapter->dev,
+						 adapter->cmp_pages * PAGE_SIZE,
+						 &adapter->cmpRingPA);
+	if (!adapter->cmp_ring)
+		return -ENOMEM;
+
+	BUG_ON(!IS_ALIGNED(adapter->ringStatePA, PAGE_SIZE));
+	BUG_ON(!IS_ALIGNED(adapter->reqRingPA, PAGE_SIZE));
+	BUG_ON(!IS_ALIGNED(adapter->cmpRingPA, PAGE_SIZE));
+
+	if (!adapter->use_msg)
+		return 0;
+
+	adapter->msg_pages = min(PVSCSI_MAX_NUM_PAGES_MSG_RING,
+				 pvscsi_msg_ring_pages);
+	adapter->msg_ring = pci_alloc_consistent(adapter->dev,
+						 adapter->msg_pages * PAGE_SIZE,
+						 &adapter->msgRingPA);
+	if (!adapter->msg_ring)
+		return -ENOMEM;
+	BUG_ON(!IS_ALIGNED(adapter->msgRingPA, PAGE_SIZE));
+
+	return 0;
+}
+
+static void pvscsi_setup_all_rings(const struct pvscsi_adapter *adapter)
+{
+	struct PVSCSICmdDescSetupRings cmd = { 0 };
+	dma_addr_t base;
+	unsigned i;
+
+	cmd.ringsStatePPN   = adapter->ringStatePA >> PAGE_SHIFT;
+	cmd.reqRingNumPages = adapter->req_pages;
+	cmd.cmpRingNumPages = adapter->cmp_pages;
+
+	base = adapter->reqRingPA;
+	for (i = 0; i < adapter->req_pages; i++) {
+		cmd.reqRingPPNs[i] = base >> PAGE_SHIFT;
+		base += PAGE_SIZE;
+	}
+
+	base = adapter->cmpRingPA;
+	for (i = 0; i < adapter->cmp_pages; i++) {
+		cmd.cmpRingPPNs[i] = base >> PAGE_SHIFT;
+		base += PAGE_SIZE;
+	}
+
+	memset(adapter->rings_state, 0, PAGE_SIZE);
+	memset(adapter->req_ring, 0, adapter->req_pages * PAGE_SIZE);
+	memset(adapter->cmp_ring, 0, adapter->cmp_pages * PAGE_SIZE);
+
+	pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_SETUP_RINGS,
+			      &cmd, sizeof(cmd));
+
+	if (adapter->use_msg) {
+		struct PVSCSICmdDescSetupMsgRing cmd_msg = { 0 };
+
+		cmd_msg.numPages = adapter->msg_pages;
+
+		base = adapter->msgRingPA;
+		for (i = 0; i < adapter->msg_pages; i++) {
+			cmd_msg.ringPPNs[i] = base >> PAGE_SHIFT;
+			base += PAGE_SIZE;
+		}
+		memset(adapter->msg_ring, 0, adapter->msg_pages * PAGE_SIZE);
+
+		pvscsi_write_cmd_desc(adapter, PVSCSI_CMD_SETUP_MSG_RING,
+				      &cmd_msg, sizeof(cmd_msg));
+	}
+}
+
+/*
+ * Pull a completion descriptor off and pass the completion back
+ * to the SCSI mid layer.
+ */
+static void pvscsi_complete_request(struct pvscsi_adapter *adapter,
+				    const struct PVSCSIRingCmpDesc *e)
+{
+	struct pvscsi_ctx *ctx;
+	struct scsi_cmnd *cmd;
+	u32 btstat = e->hostStatus;
+	u32 sdstat = e->scsiStatus;
+
+	ctx = pvscsi_get_context(adapter, e->context);
+	cmd = ctx->cmd;
+	pvscsi_unmap_buffers(adapter, ctx);
+	pvscsi_release_context(adapter, ctx);
+	cmd->result = 0;
+
+	if (sdstat != SAM_STAT_GOOD &&
+	    (btstat == BTSTAT_SUCCESS ||
+	     btstat == BTSTAT_LINKED_COMMAND_COMPLETED ||
+	     btstat == BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG)) {
+		cmd->result = (DID_OK << 16) | sdstat;
+		if (sdstat == SAM_STAT_CHECK_CONDITION && cmd->sense_buffer)
+			cmd->result |= (DRIVER_SENSE << 24);
+	} else
+		switch (btstat) {
+		case BTSTAT_SUCCESS:
+		case BTSTAT_LINKED_COMMAND_COMPLETED:
+		case BTSTAT_LINKED_COMMAND_COMPLETED_WITH_FLAG:
+			/* If everything went fine, let's move on..  */
+			cmd->result = (DID_OK << 16);
+			break;
+
+		case BTSTAT_DATARUN:
+		case BTSTAT_DATA_UNDERRUN:
+			/* Report residual data in underruns */
+			scsi_set_resid(cmd, scsi_bufflen(cmd) - e->dataLen);
+			cmd->result = (DID_ERROR << 16);
+			break;
+
+		case BTSTAT_SELTIMEO:
+			/* Our emulation returns this for non-connected devs */
+			cmd->result = (DID_BAD_TARGET << 16);
+			break;
+
+		case BTSTAT_LUNMISMATCH:
+		case BTSTAT_TAGREJECT:
+		case BTSTAT_BADMSG:
+			cmd->result = (DRIVER_INVALID << 24);
+			/* fall through */
+
+		case BTSTAT_HAHARDWARE:
+		case BTSTAT_INVPHASE:
+		case BTSTAT_HATIMEOUT:
+		case BTSTAT_NORESPONSE:
+		case BTSTAT_DISCONNECT:
+		case BTSTAT_HASOFTWARE:
+		case BTSTAT_BUSFREE:
+		case BTSTAT_SENSFAILED:
+			cmd->result |= (DID_ERROR << 16);
+			break;
+
+		case BTSTAT_SENTRST:
+		case BTSTAT_RECVRST:
+		case BTSTAT_BUSRESET:
+			cmd->result = (DID_RESET << 16);
+			break;
+
+		case BTSTAT_ABORTQUEUE:
+			cmd->result = (DID_ABORT << 16);
+			break;
+
+		case BTSTAT_SCSIPARITY:
+			cmd->result = (DID_PARITY << 16);
+			break;
+
+		default:
+			cmd->result = (DID_ERROR << 16);
+			scmd_printk(KERN_DEBUG, cmd,
+				    "Unknown completion status: 0x%x\n",
+				    btstat);
+	}
+
+	dev_dbg(&cmd->device->sdev_gendev,
+		"cmd=%p %x ctx=%p result=0x%x status=0x%x,%x\n",
+		cmd, cmd->cmnd[0], ctx, cmd->result, btstat, sdstat);
+
+	cmd->scsi_done(cmd);
+}
+
+/*
+ * barrier usage : Since the PVSCSI device is emulated, there could be cases
+ * where we may want to serialize some accesses between the driver and the
+ * emulation layer. We use compiler barriers instead of the more expensive
+ * memory barriers because PVSCSI is only supported on X86 which has strong
+ * memory access ordering.
+ */
+static void pvscsi_process_completion_ring(struct pvscsi_adapter *adapter)
+{
+	struct PVSCSIRingsState *s = adapter->rings_state;
+	struct PVSCSIRingCmpDesc *ring = adapter->cmp_ring;
+	u32 cmp_entries = s->cmpNumEntriesLog2;
+
+	while (s->cmpConsIdx != s->cmpProdIdx) {
+		struct PVSCSIRingCmpDesc *e = ring + (s->cmpConsIdx &
+						      MASK(cmp_entries));
+		/*
+		 * This barrier() ensures that *e is not dereferenced while
+		 * the device emulation still writes data into the slot.
+		 * Since the device emulation advances s->cmpProdIdx only after
+		 * updating the slot we want to check it first.
+		 */
+		barrier();
+		pvscsi_complete_request(adapter, e);
+		/*
+		 * This barrier() ensures that compiler doesn't reorder write
+		 * to s->cmpConsIdx before the read of (*e) inside
+		 * pvscsi_complete_request. Otherwise, device emulation may
+		 * overwrite *e before we had a chance to read it.
+		 */
+		barrier();
+		s->cmpConsIdx++;
+	}
+}
+
+/*
+ * Translate a Linux SCSI request into a request ring entry.
+ */
+static int pvscsi_queue_ring(struct pvscsi_adapter *adapter,
+			     struct pvscsi_ctx *ctx, struct scsi_cmnd *cmd)
+{
+	struct PVSCSIRingsState *s;
+	struct PVSCSIRingReqDesc *e;
+	struct scsi_device *sdev;
+	u32 req_entries;
+
+	s = adapter->rings_state;
+	sdev = cmd->device;
+	req_entries = s->reqNumEntriesLog2;
+
+	/*
+	 * If this condition holds, we might have room on the request ring, but
+	 * we might not have room on the completion ring for the response.
+	 * However, we have already ruled out this possibility - we would not
+	 * have successfully allocated a context if it were true, since we only
+	 * have one context per request entry.  Check for it anyway, since it
+	 * would be a serious bug.
+	 */
+	if (s->reqProdIdx - s->cmpConsIdx >= 1 << req_entries) {
+		scmd_printk(KERN_ERR, cmd, "vmw_pvscsi: "
+			    "ring full: reqProdIdx=%d cmpConsIdx=%d\n",
+			    s->reqProdIdx, s->cmpConsIdx);
+		return -1;
+	}
+
+	e = adapter->req_ring + (s->reqProdIdx & MASK(req_entries));
+
+	e->bus    = sdev->channel;
+	e->target = sdev->id;
+	memset(e->lun, 0, sizeof(e->lun));
+	e->lun[1] = sdev->lun;
+
+	if (cmd->sense_buffer) {
+		ctx->sensePA = pci_map_single(adapter->dev, cmd->sense_buffer,
+					      SCSI_SENSE_BUFFERSIZE,
+					      PCI_DMA_FROMDEVICE);
+		e->senseAddr = ctx->sensePA;
+		e->senseLen = SCSI_SENSE_BUFFERSIZE;
+	} else {
+		e->senseLen  = 0;
+		e->senseAddr = 0;
+	}
+	e->cdbLen   = cmd->cmd_len;
+	e->vcpuHint = smp_processor_id();
+	memcpy(e->cdb, cmd->cmnd, e->cdbLen);
+
+	e->tag = SIMPLE_QUEUE_TAG;
+	if (sdev->tagged_supported &&
+	    (cmd->tag == HEAD_OF_QUEUE_TAG ||
+	     cmd->tag == ORDERED_QUEUE_TAG))
+		e->tag = cmd->tag;
+
+	if (cmd->sc_data_direction == DMA_FROM_DEVICE)
+		e->flags = PVSCSI_FLAG_CMD_DIR_TOHOST;
+	else if (cmd->sc_data_direction == DMA_TO_DEVICE)
+		e->flags = PVSCSI_FLAG_CMD_DIR_TODEVICE;
+	else if (cmd->sc_data_direction == DMA_NONE)
+		e->flags = PVSCSI_FLAG_CMD_DIR_NONE;
+	else
+		e->flags = 0;
+
+	pvscsi_map_buffers(adapter, ctx, cmd, e);
+
+	e->context = pvscsi_map_context(adapter, ctx);
+
+	barrier();
+
+	s->reqProdIdx++;
+
+	return 0;
+}
+
+static int pvscsi_queue(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
+{
+	struct Scsi_Host *host = cmd->device->host;
+	struct pvscsi_adapter *adapter = shost_priv(host);
+	struct pvscsi_ctx *ctx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&adapter->hw_lock, flags);
+
+	ctx = pvscsi_acquire_context(adapter, cmd);
+	if (!ctx || pvscsi_queue_ring(adapter, ctx, cmd) != 0) {
+		if (ctx)
+			pvscsi_release_context(adapter, ctx);
+		spin_unlock_irqrestore(&adapter->hw_lock, flags);
+		return SCSI_MLQUEUE_HOST_BUSY;
+	}
+
+	cmd->scsi_done = done;
+
+	dev_dbg(&cmd->device->sdev_gendev,
+		"queued cmd %p, ctx %p, op=%x\n", cmd, ctx, cmd->cmnd[0]);
+
+	spin_unlock_irqrestore(&adapter->hw_lock, flags);
+
+	pvscsi_kick_io(adapter, cmd->cmnd[0]);
+
+	return 0;
+}
+
+static int pvscsi_abort(struct scsi_cmnd *cmd)
+{
+	struct pvscsi_adapter *adapter = shost_priv(cmd->device->host);
+	struct pvscsi_ctx *ctx;
+	unsigned long flags;
+
+	scmd_printk(KERN_DEBUG, cmd, "task abort on host %u, %p\n",
+		    adapter->host->host_no, cmd);
+
+	spin_lock_irqsave(&adapter->hw_lock, flags);
+
+	/*
+	 * Poll the completion ring first - we might be trying to abort
+	 * a command that is waiting to be dispatched in the completion ring.
+	 */
+	pvscsi_process_completion_ring(adapter);
+
+	/*
+	 * If there is no context for the command, it either already succeeded
+	 * or else was never properly issued.  Not our problem.
+	 */
+	ctx = pvscsi_find_context(adapter, cmd);
+	if (!ctx) {
+		scmd_printk(KERN_DEBUG, cmd, "Failed to abort cmd %p\n", cmd);
+		goto out;
+	}
+
+	pvscsi_abort_cmd(adapter, ctx);
+
+	pvscsi_process_completion_ring(adapter);
+
+out:
+	spin_unlock_irqrestore(&adapter->hw_lock, flags);
+	return SUCCESS;
+}
+
+/*
+ * Abort all outstanding requests.  This is only safe to use if the completion
+ * ring will never be walked again or the device has been reset, because it
+ * destroys the 1-1 mapping between context field passed to emulation and our
+ * request structure.
+ */
+static void pvscsi_reset_all(struct pvscsi_adapter *adapter)
+{
+	unsigned i;
+
+	for (i = 0; i < adapter->req_depth; i++) {
+		struct pvscsi_ctx *ctx = &adapter->cmd_map[i];
+		struct scsi_cmnd *cmd = ctx->cmd;
+		if (cmd) {
+			scmd_printk(KERN_ERR, cmd,
+				    "Forced reset on cmd %p\n", cmd);
+			pvscsi_unmap_buffers(adapter, ctx);
+			pvscsi_release_context(adapter, ctx);
+			cmd->result = (DID_RESET << 16);
+			cmd->scsi_done(cmd);
+		}
+	}
+}
+
+static int pvscsi_host_reset(struct scsi_cmnd *cmd)
+{
+	struct Scsi_Host *host = cmd->device->host;
+	struct pvscsi_adapter *adapter = shost_priv(host);
+	unsigned long flags;
+	bool use_msg;
+
+	scmd_printk(KERN_INFO, cmd, "SCSI Host reset\n");
+
+	spin_lock_irqsave(&adapter->hw_lock, flags);
+
+	use_msg = adapter->use_msg;
+
+	if (use_msg) {
+		adapter->use_msg = 0;
+		spin_unlock_irqrestore(&adapter->hw_lock, flags);
+
+		/*
+		 * Now that we know that the ISR won't add more work on the
+		 * workqueue we can safely flush any outstanding work.
+		 */
+		flush_workqueue(adapter->workqueue);
+		spin_lock_irqsave(&adapter->hw_lock, flags);
+	}
+
+	/*
+	 * We're going to tear down the entire ring structure and set it back
+	 * up, so stalling new requests until all completions are flushed and
+	 * the rings are back in place.
+	 */
+
+	pvscsi_process_request_ring(adapter);
+
+	ll_adapter_reset(adapter);
+
+	/*
+	 * Now process any completions.  Note we do this AFTER adapter reset,
+	 * which is strange, but stops races where completions get posted
+	 * between processing the ring and issuing the reset.  The backend will
+	 * not touch the ring memory after reset, so the immediately pre-reset
+	 * completion ring state is still valid.
+	 */
+	pvscsi_process_completion_ring(adapter);
+
+	pvscsi_reset_all(adapter);
+	adapter->use_msg = use_msg;
+	pvscsi_setup_all_rings(adapter);
+	pvscsi_unmask_intr(adapter);
+
+	spin_unlock_irqrestore(&adapter->hw_lock, flags);
+
+	return SUCCESS;
+}
+
+static int pvscsi_bus_reset(struct scsi_cmnd *cmd)
+{
+	struct Scsi_Host *host = cmd->device->host;
+	struct pvscsi_adapter *adapter = shost_priv(host);
+	unsigned long flags;
+
+	scmd_printk(KERN_INFO, cmd, "SCSI Bus reset\n");
+
+	/*
+	 * We don't want to queue new requests for this bus after
+	 * flushing all pending requests to emulation, since new
+	 * requests could then sneak in during this bus reset phase,
+	 * so take the lock now.
+	 */
+	spin_lock_irqsave(&adapter->hw_lock, flags);
+
+	pvscsi_process_request_ring(adapter);
+	ll_bus_reset(adapter);
+	pvscsi_process_completion_ring(adapter);
+
+	spin_unlock_irqrestore(&adapter->hw_lock, flags);
+
+	return SUCCESS;
+}
+
+static int pvscsi_device_reset(struct scsi_cmnd *cmd)
+{
+	struct Scsi_Host *host = cmd->device->host;
+	struct pvscsi_adapter *adapter = shost_priv(host);
+	unsigned long flags;
+
+	scmd_printk(KERN_INFO, cmd, "SCSI device reset on scsi%u:%u\n",
+		    host->host_no, cmd->device->id);
+
+	/*
+	 * We don't want to queue new requests for this device after flushing
+	 * all pending requests to emulation, since new requests could then
+	 * sneak in during this device reset phase, so take the lock now.
+	 */
+	spin_lock_irqsave(&adapter->hw_lock, flags);
+
+	pvscsi_process_request_ring(adapter);
+	ll_device_reset(adapter, cmd->device->id);
+	pvscsi_process_completion_ring(adapter);
+
+	spin_unlock_irqrestore(&adapter->hw_lock, flags);
+
+	return SUCCESS;
+}
+
+static struct scsi_host_template pvscsi_template;
+
+static const char *pvscsi_info(struct Scsi_Host *host)
+{
+	struct pvscsi_adapter *adapter = shost_priv(host);
+	static char buf[256];
+
+	sprintf(buf, "VMware PVSCSI storage adapter rev %d, req/cmp/msg rings: "
+		"%u/%u/%u pages, cmd_per_lun=%u", adapter->rev,
+		adapter->req_pages, adapter->cmp_pages, adapter->msg_pages,
+		pvscsi_template.cmd_per_lun);
+
+	return buf;
+}
+
+static struct scsi_host_template pvscsi_template = {
+	.module				= THIS_MODULE,
+	.name				= "VMware PVSCSI Host Adapter",
+	.proc_name			= "vmw_pvscsi",
+	.info				= pvscsi_info,
+	.queuecommand			= pvscsi_queue,
+	.this_id			= -1,
+	.sg_tablesize			= PVSCSI_MAX_NUM_SG_ENTRIES_PER_SEGMENT,
+	.dma_boundary			= UINT_MAX,
+	.max_sectors			= 0xffff,
+	.use_clustering			= ENABLE_CLUSTERING,
+	.eh_abort_handler		= pvscsi_abort,
+	.eh_device_reset_handler	= pvscsi_device_reset,
+	.eh_bus_reset_handler		= pvscsi_bus_reset,
+	.eh_host_reset_handler		= pvscsi_host_reset,
+};
+
+static void pvscsi_process_msg(const struct pvscsi_adapter *adapter,
+			       const struct PVSCSIRingMsgDesc *e)
+{
+	struct PVSCSIRingsState *s = adapter->rings_state;
+	struct Scsi_Host *host = adapter->host;
+	struct scsi_device *sdev;
+
+	printk(KERN_INFO "vmw_pvscsi: msg type: 0x%x - MSG RING: %u/%u (%u) \n",
+	       e->type, s->msgProdIdx, s->msgConsIdx, s->msgNumEntriesLog2);
+
+	BUILD_BUG_ON(PVSCSI_MSG_LAST != 2);
+
+	if (e->type == PVSCSI_MSG_DEV_ADDED) {
+		struct PVSCSIMsgDescDevStatusChanged *desc;
+		desc = (struct PVSCSIMsgDescDevStatusChanged *)e;
+
+		printk(KERN_INFO
+		       "vmw_pvscsi: msg: device added at scsi%u:%u:%u\n",
+		       desc->bus, desc->target, desc->lun[1]);
+
+		if (!scsi_host_get(host))
+			return;
+
+		sdev = scsi_device_lookup(host, desc->bus, desc->target,
+					  desc->lun[1]);
+		if (sdev) {
+			printk(KERN_INFO "vmw_pvscsi: device already exists\n");
+			scsi_device_put(sdev);
+		} else
+			scsi_add_device(adapter->host, desc->bus,
+					desc->target, desc->lun[1]);
+
+		scsi_host_put(host);
+	} else if (e->type == PVSCSI_MSG_DEV_REMOVED) {
+		struct PVSCSIMsgDescDevStatusChanged *desc;
+		desc = (struct PVSCSIMsgDescDevStatusChanged *)e;
+
+		printk(KERN_INFO
+		       "vmw_pvscsi: msg: device removed at scsi%u:%u:%u\n",
+		       desc->bus, desc->target, desc->lun[1]);
+
+		if (!scsi_host_get(host))
+			return;
+
+		sdev = scsi_device_lookup(host, desc->bus, desc->target,
+					  desc->lun[1]);
+		if (sdev) {
+			scsi_remove_device(sdev);
+			scsi_device_put(sdev);
+		} else
+			printk(KERN_INFO
+			       "vmw_pvscsi: failed to lookup scsi%u:%u:%u\n",
+			       desc->bus, desc->target, desc->lun[1]);
+
+		scsi_host_put(host);
+	}
+}
+
+static int pvscsi_msg_pending(const struct pvscsi_adapter *adapter)
+{
+	struct PVSCSIRingsState *s = adapter->rings_state;
+
+	return s->msgProdIdx != s->msgConsIdx;
+}
+
+static void pvscsi_process_msg_ring(const struct pvscsi_adapter *adapter)
+{
+	struct PVSCSIRingsState *s = adapter->rings_state;
+	struct PVSCSIRingMsgDesc *ring = adapter->msg_ring;
+	u32 msg_entries = s->msgNumEntriesLog2;
+
+	while (pvscsi_msg_pending(adapter)) {
+		struct PVSCSIRingMsgDesc *e = ring + (s->msgConsIdx &
+						      MASK(msg_entries));
+
+		barrier();
+		pvscsi_process_msg(adapter, e);
+		barrier();
+		s->msgConsIdx++;
+	}
+}
+
+static void pvscsi_msg_workqueue_handler(struct work_struct *data)
+{
+	struct pvscsi_adapter *adapter;
+
+	adapter = container_of(data, struct pvscsi_adapter, work);
+
+	pvscsi_process_msg_ring(adapter);
+}
+
+static int pvscsi_setup_msg_workqueue(struct pvscsi_adapter *adapter)
+{
+	char name[32];
+
+	if (!pvscsi_use_msg)
+		return 0;
+
+	pvscsi_reg_write(adapter, PVSCSI_REG_OFFSET_COMMAND,
+			 PVSCSI_CMD_SETUP_MSG_RING);
+
+	if (pvscsi_reg_read(adapter, PVSCSI_REG_OFFSET_COMMAND_STATUS) == -1)
+		return 0;
+
+	snprintf(name, sizeof(name),
+		 "vmw_pvscsi_wq_%u", adapter->host->host_no);
+
+	adapter->workqueue = create_singlethread_workqueue(name);
+	if (!adapter->workqueue) {
+		printk(KERN_ERR "vmw_pvscsi: failed to create work queue\n");
+		return 0;
+	}
+	INIT_WORK(&adapter->work, pvscsi_msg_workqueue_handler);
+
+	return 1;
+}
+
+static irqreturn_t pvscsi_isr(int irq, void *devp)
+{
+	struct pvscsi_adapter *adapter = devp;
+	int handled;
+
+	if (adapter->use_msi || adapter->use_msix)
+		handled = true;
+	else {
+		u32 val = pvscsi_read_intr_status(adapter);
+		handled = (val & PVSCSI_INTR_ALL_SUPPORTED) != 0;
+		if (handled)
+			pvscsi_write_intr_status(devp, val);
+	}
+
+	if (handled) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&adapter->hw_lock, flags);
+
+		pvscsi_process_completion_ring(adapter);
+		if (adapter->use_msg && pvscsi_msg_pending(adapter))
+			queue_work(adapter->workqueue, &adapter->work);
+
+		spin_unlock_irqrestore(&adapter->hw_lock, flags);
+	}
+
+	return IRQ_RETVAL(handled);
+}
+
+static void pvscsi_free_sgls(const struct pvscsi_adapter *adapter)
+{
+	struct pvscsi_ctx *ctx = adapter->cmd_map;
+	unsigned i;
+
+	for (i = 0; i < adapter->req_depth; ++i, ++ctx)
+		free_pages((unsigned long)ctx->sgl, get_order(SGL_SIZE));
+}
+
+static int pvscsi_setup_msix(const struct pvscsi_adapter *adapter, int *irq)
+{
+	struct msix_entry entry = { 0, PVSCSI_VECTOR_COMPLETION };
+	int ret;
+
+	ret = pci_enable_msix(adapter->dev, &entry, 1);
+	if (ret)
+		return ret;
+
+	*irq = entry.vector;
+
+	return 0;
+}
+
+static void pvscsi_shutdown_intr(struct pvscsi_adapter *adapter)
+{
+	if (adapter->irq) {
+		free_irq(adapter->irq, adapter);
+		adapter->irq = 0;
+	}
+	if (adapter->use_msi) {
+		pci_disable_msi(adapter->dev);
+		adapter->use_msi = 0;
+	} else if (adapter->use_msix) {
+		pci_disable_msix(adapter->dev);
+		adapter->use_msix = 0;
+	}
+}
+
+static void pvscsi_release_resources(struct pvscsi_adapter *adapter)
+{
+	pvscsi_shutdown_intr(adapter);
+
+	if (adapter->workqueue)
+		destroy_workqueue(adapter->workqueue);
+
+	if (adapter->mmioBase)
+		pci_iounmap(adapter->dev, adapter->mmioBase);
+
+	pci_release_regions(adapter->dev);
+
+	if (adapter->cmd_map) {
+		pvscsi_free_sgls(adapter);
+		kfree(adapter->cmd_map);
+	}
+
+	if (adapter->rings_state)
+		pci_free_consistent(adapter->dev, PAGE_SIZE,
+				    adapter->rings_state, adapter->ringStatePA);
+
+	if (adapter->req_ring)
+		pci_free_consistent(adapter->dev,
+				    adapter->req_pages * PAGE_SIZE,
+				    adapter->req_ring, adapter->reqRingPA);
+
+	if (adapter->cmp_ring)
+		pci_free_consistent(adapter->dev,
+				    adapter->cmp_pages * PAGE_SIZE,
+				    adapter->cmp_ring, adapter->cmpRingPA);
+
+	if (adapter->msg_ring)
+		pci_free_consistent(adapter->dev,
+				    adapter->msg_pages * PAGE_SIZE,
+				    adapter->msg_ring, adapter->msgRingPA);
+}
+
+/*
+ * Allocate scatter gather lists.
+ *
+ * These are statically allocated.  Trying to be clever was not worth it.
+ *
+ * Dynamic allocation can fail, and we can't go deeep into the memory
+ * allocator, since we're a SCSI driver, and trying too hard to allocate
+ * memory might generate disk I/O.  We also don't want to fail disk I/O
+ * in that case because we can't get an allocation - the I/O could be
+ * trying to swap out data to free memory.  Since that is pathological,
+ * just use a statically allocated scatter list.
+ *
+ */
+static int __devinit pvscsi_allocate_sg(struct pvscsi_adapter *adapter)
+{
+	struct pvscsi_ctx *ctx;
+	int i;
+
+	ctx = adapter->cmd_map;
+	BUILD_BUG_ON(sizeof(struct pvscsi_sg_list) > SGL_SIZE);
+
+	for (i = 0; i < adapter->req_depth; ++i, ++ctx) {
+		ctx->sgl = (void *)__get_free_pages(GFP_KERNEL,
+						    get_order(SGL_SIZE));
+		ctx->sglPA = 0;
+		BUG_ON(!IS_ALIGNED(((unsigned long)ctx->sgl), PAGE_SIZE));
+		if (!ctx->sgl) {
+			for (; i >= 0; --i, --ctx) {
+				free_pages((unsigned long)ctx->sgl,
+					   get_order(SGL_SIZE));
+				ctx->sgl = NULL;
+			}
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+static int __devinit pvscsi_probe(struct pci_dev *pdev,
+				  const struct pci_device_id *id)
+{
+	struct pvscsi_adapter *adapter;
+	struct Scsi_Host *host;
+	unsigned int i;
+	unsigned long flags = 0;
+	int error;
+
+	error = -ENODEV;
+
+	if (pci_enable_device(pdev))
+		return error;
+
+	if (pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) == 0 &&
+	    pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64)) == 0) {
+		printk(KERN_INFO "vmw_pvscsi: using 64bit dma\n");
+	} else if (pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) == 0 &&
+		   pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)) == 0) {
+		printk(KERN_INFO "vmw_pvscsi: using 32bit dma\n");
+	} else {
+		printk(KERN_ERR "vmw_pvscsi: failed to set DMA mask\n");
+		goto out_disable_device;
+	}
+
+	pvscsi_template.can_queue =
+		min(PVSCSI_MAX_NUM_PAGES_REQ_RING, pvscsi_ring_pages) *
+		PVSCSI_MAX_NUM_REQ_ENTRIES_PER_PAGE;
+	pvscsi_template.cmd_per_lun =
+		min(pvscsi_template.can_queue, pvscsi_cmd_per_lun);
+	host = scsi_host_alloc(&pvscsi_template, sizeof(struct pvscsi_adapter));
+	if (!host) {
+		printk(KERN_ERR "vmw_pvscsi: failed to allocate host\n");
+		goto out_disable_device;
+	}
+
+	adapter = shost_priv(host);
+	memset(adapter, 0, sizeof(*adapter));
+	adapter->dev  = pdev;
+	adapter->host = host;
+
+	spin_lock_init(&adapter->hw_lock);
+
+	host->max_channel = 0;
+	host->max_id      = 16;
+	host->max_lun     = 1;
+	host->max_cmd_len = 16;
+
+	adapter->rev = pdev->revision;
+
+	if (pci_request_regions(pdev, "vmw_pvscsi")) {
+		printk(KERN_ERR "vmw_pvscsi: pci memory selection failed\n");
+		goto out_free_host;
+	}
+
+	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
+		if ((pci_resource_flags(pdev, i) & PCI_BASE_ADDRESS_SPACE_IO))
+			continue;
+
+		if (pci_resource_len(pdev, i) < PVSCSI_MEM_SPACE_SIZE)
+			continue;
+
+		break;
+	}
+
+	if (i == DEVICE_COUNT_RESOURCE) {
+		printk(KERN_ERR
+		       "vmw_pvscsi: adapter has no suitable MMIO region\n");
+		goto out_release_resources;
+	}
+
+	adapter->mmioBase = pci_iomap(pdev, i, PVSCSI_MEM_SPACE_SIZE);
+
+	if (!adapter->mmioBase) {
+		printk(KERN_ERR
+		       "vmw_pvscsi: can't iomap for BAR %d memsize %lu\n",
+		       i, PVSCSI_MEM_SPACE_SIZE);
+		goto out_release_resources;
+	}
+
+	pci_set_master(pdev);
+	pci_set_drvdata(pdev, host);
+
+	ll_adapter_reset(adapter);
+
+	adapter->use_msg = pvscsi_setup_msg_workqueue(adapter);
+
+	error = pvscsi_allocate_rings(adapter);
+	if (error) {
+		printk(KERN_ERR "vmw_pvscsi: unable to allocate ring memory\n");
+		goto out_release_resources;
+	}
+
+	/*
+	 * From this point on we should reset the adapter if anything goes
+	 * wrong.
+	 */
+	pvscsi_setup_all_rings(adapter);
+
+	adapter->cmd_map = kcalloc(adapter->req_depth,
+				   sizeof(struct pvscsi_ctx), GFP_KERNEL);
+	if (!adapter->cmd_map) {
+		printk(KERN_ERR "vmw_pvscsi: failed to allocate memory.\n");
+		error = -ENOMEM;
+		goto out_reset_adapter;
+	}
+
+	INIT_LIST_HEAD(&adapter->cmd_pool);
+	for (i = 0; i < adapter->req_depth; i++) {
+		struct pvscsi_ctx *ctx = adapter->cmd_map + i;
+		list_add(&ctx->list, &adapter->cmd_pool);
+	}
+
+	error = pvscsi_allocate_sg(adapter);
+	if (error) {
+		printk(KERN_ERR "vmw_pvscsi: unable to allocate s/g table\n");
+		goto out_reset_adapter;
+	}
+
+	if (!pvscsi_disable_msix &&
+	    pvscsi_setup_msix(adapter, &adapter->irq) == 0) {
+		printk(KERN_INFO "vmw_pvscsi: using MSI-X\n");
+		adapter->use_msix = 1;
+	} else if (!pvscsi_disable_msi && pci_enable_msi(pdev) == 0) {
+		printk(KERN_INFO "vmw_pvscsi: using MSI\n");
+		adapter->use_msi = 1;
+		adapter->irq = pdev->irq;
+	} else {
+		printk(KERN_INFO "vmw_pvscsi: using INTx\n");
+		adapter->irq = pdev->irq;
+		flags = IRQF_SHARED;
+	}
+
+	error = request_irq(adapter->irq, pvscsi_isr, flags,
+			    "vmw_pvscsi", adapter);
+	if (error) {
+		printk(KERN_ERR
+		       "vmw_pvscsi: unable to request IRQ: %d\n", error);
+		adapter->irq = 0;
+		goto out_reset_adapter;
+	}
+
+	error = scsi_add_host(host, &pdev->dev);
+	if (error) {
+		printk(KERN_ERR
+		       "vmw_pvscsi: scsi_add_host failed: %d\n", error);
+		goto out_reset_adapter;
+	}
+
+	dev_info(&pdev->dev, "VMware PVSCSI rev %d host #%u\n",
+		 adapter->rev, host->host_no);
+
+	pvscsi_unmask_intr(adapter);
+
+	scsi_scan_host(host);
+
+	return 0;
+
+out_reset_adapter:
+	ll_adapter_reset(adapter);
+out_release_resources:
+	pvscsi_release_resources(adapter);
+out_free_host:
+	scsi_host_put(host);
+out_disable_device:
+	pci_set_drvdata(pdev, NULL);
+	pci_disable_device(pdev);
+
+	return error;
+}
+
+static void __pvscsi_shutdown(struct pvscsi_adapter *adapter)
+{
+	pvscsi_mask_intr(adapter);
+
+	if (adapter->workqueue)
+		flush_workqueue(adapter->workqueue);
+
+	pvscsi_shutdown_intr(adapter);
+
+	pvscsi_process_request_ring(adapter);
+	pvscsi_process_completion_ring(adapter);
+	ll_adapter_reset(adapter);
+}
+
+static void pvscsi_shutdown(struct pci_dev *dev)
+{
+	struct Scsi_Host *host = pci_get_drvdata(dev);
+	struct pvscsi_adapter *adapter = shost_priv(host);
+
+	__pvscsi_shutdown(adapter);
+}
+
+static void pvscsi_remove(struct pci_dev *pdev)
+{
+	struct Scsi_Host *host = pci_get_drvdata(pdev);
+	struct pvscsi_adapter *adapter = shost_priv(host);
+
+	scsi_remove_host(host);
+
+	__pvscsi_shutdown(adapter);
+	pvscsi_release_resources(adapter);
+
+	scsi_host_put(host);
+
+	pci_set_drvdata(pdev, NULL);
+	pci_disable_device(pdev);
+}
+
+static struct pci_driver pvscsi_pci_driver = {
+	.name		= "vmw_pvscsi",
+	.id_table	= pvscsi_pci_tbl,
+	.probe		= pvscsi_probe,
+	.remove		= __devexit_p(pvscsi_remove),
+	.shutdown       = pvscsi_shutdown,
+};
+
+static int __init pvscsi_init(void)
+{
+	pr_info("%s - version %s\n",
+		PVSCSI_LINUX_DRIVER_DESC, PVSCSI_DRIVER_VERSION_STRING);
+	return pci_register_driver(&pvscsi_pci_driver);
+}
+
+static void __exit pvscsi_exit(void)
+{
+	pci_unregister_driver(&pvscsi_pci_driver);
+}
+
+module_init(pvscsi_init);
+module_exit(pvscsi_exit);