Message-Id: <1228265348.6229.130.camel@haakon2.linux-iscsi.org>
Date:	Tue, 02 Dec 2008 16:49:08 -0800
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	"Linux-iSCSI.org Target Dev" 
	<linux-iscsi-target-dev@...glegroups.com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-scsi <linux-scsi@...r.kernel.org>
Subject: [PATCH] [Target_Core_Mod/PSCSI]: Use struct request to struct
	scsi_device->request_queue

>>From 1b14b5e1fc9a7074322b1015bb86eca2a8ef4560 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab@...ux-iscsi.org>
Date: Tue, 2 Dec 2008 16:30:51 -0800
Subject: [PATCH] [Target_Core_Mod/PSCSI]: Use struct request to struct scsi_device->request_queue

This patch begins to remove the usage of scsi_execute_async() from the PSCSI
subsystem plugin for v3.0 generic target core.

It uses blk_get_request() to allocate struct request in pscsi_blk_get_request()
and used by all CDB types and both memory backing types.  struct request is then
released with __blk_put_request() in the struct request->end_io() context in
pscsi_req_done().

Also, this patch adds a temporary EXPORT_SYMBOL_GPL() for
scsi/drivers/scsi_lib.c:scsi_req_map_sg() (which will also be going away at
some point).  At that point, the upstream struct scatterlist and/or
struct page -> struct request mapping for usage with struct scsi_device->request_queue
will be dropped into place in drivers/lio-core/target_core_pscsi.c:pscsi_map_task_SG()

Tested on v2.6.28-rc7 32-bit x86 with virtual VMware TYPE_DISK on virtual MPT-Fusion

Signed-off-by: Nicholas A. Bellinger <nab@...ux-iscsi.org>
---
 drivers/lio-core/target_core_pscsi.c |  206 +++++++++++++++++++++++++---------
 drivers/lio-core/target_core_pscsi.h |    5 +-
 drivers/scsi/scsi_lib.c              |    6 +-
 3 files changed, 161 insertions(+), 56 deletions(-)

diff --git a/drivers/lio-core/target_core_pscsi.c b/drivers/lio-core/target_core_pscsi.c
index ed9f588..bb46e1c 100644
--- a/drivers/lio-core/target_core_pscsi.c
+++ b/drivers/lio-core/target_core_pscsi.c
@@ -37,6 +37,7 @@
 #include <linux/spinlock.h>
 #include <linux/smp_lock.h>
 #include <linux/genhd.h>
+#include <linux/cdrom.h>
 #include <linux/file.h>
 
 #include <scsi/scsi.h>
@@ -44,6 +45,7 @@
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
 #include <sd.h>
+#include <sr.h>
 
 #include <iscsi_linux_os.h>
 #include <iscsi_linux_defs.h>
@@ -763,11 +765,11 @@ extern void *pscsi_allocate_request (
 	se_device_t *dev)
 {
 	pscsi_plugin_task_t *pt;
-	if (!(pt = kmalloc(sizeof(pscsi_plugin_task_t), GFP_KERNEL))) {
-		TRACE_ERROR("Unable to allocate pscsi_plugin_task_t\n");
+	
+	if (!(pt = kzalloc(sizeof(pscsi_plugin_task_t), GFP_KERNEL))) {
+		printk(KERN_ERR "Unable to allocate pscsi_plugin_task_t\n");
 		return(NULL);
 	}
-	memset(pt, 0, sizeof(pscsi_plugin_task_t));
 
 	return(pt);
 }
@@ -788,7 +790,44 @@ extern void pscsi_get_evpd_sn (unsigned char *buf, u32 size, se_device_t *dev)
 	return;
 }
 
-/*	pscsi_do_task(): (Part of se_subsystem_api_t template)
+static int pscsi_blk_get_request (se_task_t *task)
+{
+	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
+	pscsi_dev_virt_t *pdv = (pscsi_dev_virt_t *) task->iscsi_dev->dev_ptr;
+
+	pt->pscsi_req = blk_get_request(pdv->pdv_sd->request_queue,
+			(pt->pscsi_direction == DMA_TO_DEVICE), GFP_KERNEL);
+	if (!(pt->pscsi_req) || IS_ERR(pt->pscsi_req)) {
+		printk(KERN_ERR "PSCSI: blk_get_request() failed: %ld\n",
+				IS_ERR(pt->pscsi_req));
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+	}
+	/*
+	 * Defined as "scsi command" in include/linux/blkdev.h.
+	 */
+	pt->pscsi_req->cmd_type = REQ_TYPE_BLOCK_PC;
+	/*
+	 * Setup the done function pointer for struct request,
+	 * also set the end_io_data pointer.to se_task_t.
+	 */
+	pt->pscsi_req->end_io = pscsi_req_done;
+	pt->pscsi_req->end_io_data = (void *)task;
+	/*
+	 * Load the referenced se_task_t's SCSI CDB into
+	 * include/linux/blkdev.h:struct request->cmd
+	 */
+	pt->pscsi_req->cmd_len = COMMAND_SIZE(pt->pscsi_cdb[0]);
+	memcpy(pt->pscsi_req->cmd, pt->pscsi_cdb, pt->pscsi_req->cmd_len);
+	/*
+	 * Setup pointer for outgoing sense data.
+	 */
+	pt->pscsi_req->sense = (void *)&pt->pscsi_sense[0];
+	pt->pscsi_req->sense_len = 0;
+
+	return(0);
+}
+
+/*      pscsi_do_task(): (Part of se_subsystem_api_t template)
  *
  *
  */
@@ -796,17 +835,32 @@ extern int pscsi_do_task (se_task_t *task)
 {
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 	pscsi_dev_virt_t *pdv = (pscsi_dev_virt_t *) task->iscsi_dev->dev_ptr;
-	int ret;
-	
-	if ((ret = scsi_execute_async((struct scsi_device *)pdv->pdv_sd,
-			   pt->pscsi_cdb, COMMAND_SIZE(pt->pscsi_cdb[0]), pt->pscsi_direction,
-			   pt->pscsi_buf, task->task_size, task->task_sg_num,
-			   (task->se_obj_api->get_device_type(task->se_obj_ptr) == 0) ?
-			   PS_TIMEOUT_DISK : PS_TIMEOUT_OTHER, PS_RETRY,
-			   (void *)task, pscsi_req_done, GFP_KERNEL)) != 0) {
-		TRACE_ERROR("PSCSI Execute(): returned: %d\n", ret);
-		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
-	}	
+	struct gendisk *gd = NULL;
+	/*
+	 * Grab pointer to struct gendisk for TYPE_DISK and TYPE_ROM
+	 * cases (eg: cases where struct scsi_device has a backing
+	 * struct block_device.  Also set the struct request->timeout
+	 * value based on peripheral device type (from SCSI).
+	 */
+	if (pdv->pdv_sd->type == TYPE_DISK) {
+		struct scsi_disk *sdisk = dev_get_drvdata(
+					&pdv->pdv_sd->sdev_gendev);
+		gd = sdisk->disk;
+		pt->pscsi_req->timeout = PS_TIMEOUT_DISK;
+	} else if (pdv->pdv_sd->type == TYPE_ROM) {
+		struct scsi_cd *scd = dev_get_drvdata(
+					&pdv->pdv_sd->sdev_gendev);
+		gd = scd->disk;
+		pt->pscsi_req->timeout = PS_TIMEOUT_OTHER;
+	} else
+		pt->pscsi_req->timeout = PS_TIMEOUT_OTHER;
+
+	pt->pscsi_req->retries = PS_RETRY;
+	/*
+	 * Queue the struct request into the struct scsi_device->request_queue.
+	 */
+	blk_execute_rq_nowait(pdv->pdv_sd->request_queue, gd,
+			      pt->pscsi_req, 1, pscsi_req_done);
 
 	return(PYX_TRANSPORT_SENT_TO_TRANSPORT);
 }
@@ -817,7 +871,8 @@ extern int pscsi_do_task (se_task_t *task)
  */
 extern void pscsi_free_task (se_task_t *task)
 {
-	kfree(task->transport_req);
+	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
+	kfree(pt);
 	return;
 }
 
@@ -1099,31 +1154,64 @@ extern void __pscsi_get_dev_info (pscsi_dev_virt_t *pdv, char *b, int *bl)
 	return;
 }
 
-/*	pscsi_map_task_SG(): 
+extern int scsi_req_map_sg(struct request *, struct scatterlist *, int,  unsigned , gfp_t );
+
+/*      pscsi_map_task_SG(): 
  *
  *
  */
-extern void pscsi_map_task_SG (se_task_t *task)
+extern int pscsi_map_task_SG (se_task_t *task)
 {
         pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
+	int ret = 0;
+
 	pt->pscsi_buf = (void *)task->task_buf;
 
-	return;
+	if (!task->task_size)
+		return(0);
+#if 0
+	if ((ret = blk_rq_map_sg(pdv->pdv_sd->request_queue,
+			pt->pscsi_req,
+			(struct scatterlist *)pt->pscsi_buf)) < 0) {
+		printk(KERN_ERR "PSCSI: blk_rq_map_sg() returned %d\n", ret);
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+	}
+#else
+	if ((ret = scsi_req_map_sg(pt->pscsi_req,
+			(struct scatterlist *)pt->pscsi_buf,
+			task->task_sg_num, task->task_size,
+			GFP_KERNEL)) < 0) {
+		printk(KERN_ERR "PSCSI: scsi_req_map_sg() failed: %d\n", ret);
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+	}
+#endif
+	return(0);
 }
 
 /*	pscsi_map_task_non_SG():
  *
  *
  */
-extern void pscsi_map_task_non_SG (se_task_t *task)
+extern int pscsi_map_task_non_SG (se_task_t *task)
 {
 	iscsi_cmd_t *cmd = task->iscsi_cmd;
+	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 	unsigned char *buf = (unsigned char *) T_TASK(cmd)->t_task_buf;
+	pscsi_dev_virt_t *pdv = (pscsi_dev_virt_t *) task->iscsi_dev->dev_ptr;
+	int ret = 0;
 
-	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 	pt->pscsi_buf = (void *)buf;
 
-	return;
+	if (!task->task_size)
+		return(0);
+
+	if ((ret = blk_rq_map_kern(pdv->pdv_sd->request_queue,
+			pt->pscsi_req, pt->pscsi_buf,
+			task->task_size, GFP_KERNEL)) < 0) {
+		printk(KERN_ERR "PSCSI: blk_rq_map_kern() failed: %d\n", ret);
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+	}
+	return(0);
 }
 
 /*	pscsi_CDB_inquiry():
@@ -1135,9 +1223,10 @@ extern int pscsi_CDB_inquiry (se_task_t *task, u32 size)
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 
 	pt->pscsi_direction = DMA_FROM_DEVICE;
-	pscsi_map_task_non_SG(task);
+	if (pscsi_blk_get_request(task) < 0)
+		return(-1);
 
-	return(0);
+	return(pscsi_map_task_non_SG(task));
 }
 
 extern int pscsi_CDB_none (se_task_t *task, u32 size)
@@ -1146,7 +1235,7 @@ extern int pscsi_CDB_none (se_task_t *task, u32 size)
 
 	pt->pscsi_direction = DMA_NONE;
 
-	return(0);
+	return(pscsi_blk_get_request(task));
 }
 
 /*	pscsi_CDB_read_non_SG():
@@ -1158,9 +1247,11 @@ extern int pscsi_CDB_read_non_SG (se_task_t *task, u32 size)
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 
 	pt->pscsi_direction = DMA_FROM_DEVICE;
-	pscsi_map_task_non_SG(task);
 
-	return(0);
+	if (pscsi_blk_get_request(task) < 0)
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+
+	return(pscsi_map_task_non_SG(task));
 }
 
 /*	pscsi_CDB_read_SG():
@@ -1172,7 +1263,12 @@ extern int pscsi_CDB_read_SG (se_task_t *task, u32 size)
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 
 	pt->pscsi_direction = DMA_FROM_DEVICE;
-	pscsi_map_task_SG(task);
+
+	if (pscsi_blk_get_request(task) < 0)
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+
+	if (pscsi_map_task_SG(task) < 0)
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
 
 	return(task->task_sg_num);
 }
@@ -1186,9 +1282,11 @@ extern int pscsi_CDB_write_non_SG (se_task_t *task, u32 size)
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 
 	pt->pscsi_direction = DMA_TO_DEVICE;
-	pscsi_map_task_non_SG(task);
 
-	return(0);
+	if (pscsi_blk_get_request(task) < 0)
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+
+	return(pscsi_map_task_non_SG(task));
 }
 
 /*	pscsi_CDB_write_SG():
@@ -1200,7 +1298,12 @@ extern int pscsi_CDB_write_SG (se_task_t *task, u32 size)
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *) task->transport_req;
 
 	pt->pscsi_direction = DMA_TO_DEVICE;
-	pscsi_map_task_SG(task);
+
+	if (pscsi_blk_get_request(task) < 0)
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
+
+	if (pscsi_map_task_SG(task) < 0)
+		return(PYX_TRANSPORT_LOGICAL_UNIT_COMMUNICATION_FAILURE);
 	
 	return(task->task_sg_num);
 }
@@ -1386,22 +1489,25 @@ extern void pscsi_shutdown_hba (se_hba_t *hba)
  *
  *
  */
-//#warning FIXME: We can do some custom handling of HBA fuckups here.
-extern inline void pscsi_process_SAM_status (se_task_t *task, unsigned char *cdb, int result)
+static inline void pscsi_process_SAM_status (
+	se_task_t *task,
+	pscsi_plugin_task_t *pt)
 {
-	if ((task->task_scsi_status = status_byte(result))) {
+	if ((task->task_scsi_status = status_byte(pt->pscsi_result))) {
 		task->task_scsi_status <<= 1;
-		PYXPRINT("Parallel SCSI Status Byte exception - ITT: 0x%08x Task: %p CDB: 0x%02x"
-			" Result: 0x%08x\n", task->iscsi_cmd->init_task_tag, task, cdb[0], result);
+		PYXPRINT("PSCSI Status Byte exception at task: %p CDB: 0x%02x"
+			" Result: 0x%08x\n", task, pt->pscsi_cdb[0],
+			pt->pscsi_result);
 	}
 
-	switch (host_byte(result)) {
+	switch (host_byte(pt->pscsi_result)) {
 	case DID_OK:
 		transport_complete_task(task, (!task->task_scsi_status));
 		break;
 	default:
-		PYXPRINT("Parallel SCSI Host Byte exception - ITT: 0x%08x Task: %p CDB: 0x%02x"
-			" Result: 0x%08x\n", task->iscsi_cmd->init_task_tag, task, cdb[0], result);
+		PYXPRINT("PSCSI Host Byte exception at task: %p CDB: 0x%02x"
+			" Result: 0x%08x\n", task, pt->pscsi_cdb[0],
+			pt->pscsi_result);
 		task->task_scsi_status = SAM_STAT_CHECK_CONDITION;
 		task->task_error_status = PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
 		task->iscsi_cmd->transport_error_status = PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
@@ -1412,21 +1518,17 @@ extern inline void pscsi_process_SAM_status (se_task_t *task, unsigned char *cdb
 	return;
 }
 
-extern void pscsi_req_done (void *data, char *sense, int result, int data_len)
+extern void pscsi_req_done (struct request *req, int uptodate)
 {
-	se_task_t *task = (se_task_t *)data;
+	se_task_t *task = (se_task_t *)req->end_io_data;	
 	pscsi_plugin_task_t *pt = (pscsi_plugin_task_t *)task->transport_req;
-#if 0
-	printk("pscsi_req_done(): result: %08x, sense: %p data_len: %d\n",
-			result, sense, data_len);
-#endif	
-	pt->pscsi_result = result;
-	pt->pscsi_data_len = data_len;
-
-	if (result != 0)
-		memcpy(pt->pscsi_sense, sense, SCSI_SENSE_BUFFERSIZE);
+
+	pt->pscsi_result = req->errors;
+	pt->pscsi_resid = req->data_len;
 	
-	pscsi_process_SAM_status(task, &pt->pscsi_cdb[0], result);
+	pscsi_process_SAM_status(task, pt);
+	__blk_put_request(req->q, req);
+	pt->pscsi_req = NULL;
+
 	return;
 }
-
diff --git a/drivers/lio-core/target_core_pscsi.h b/drivers/lio-core/target_core_pscsi.h
index 980587d..090f0d2 100644
--- a/drivers/lio-core/target_core_pscsi.h
+++ b/drivers/lio-core/target_core_pscsi.h
@@ -90,7 +90,7 @@ extern struct scatterlist *pscsi_get_SG (se_task_t *);
 extern u32 pscsi_get_SG_count (se_task_t *);
 extern int pscsi_set_non_SG_buf (unsigned char *, se_task_t *);
 extern void pscsi_shutdown_hba (struct se_hba_s *);
-extern void pscsi_req_done (void *, char *, int, int);
+extern void pscsi_req_done (struct request *, int);
 #endif
 
 #include <linux/device.h>
@@ -104,8 +104,9 @@ typedef struct pscsi_plugin_task_s {
 	unsigned char pscsi_sense[SCSI_SENSE_BUFFERSIZE];
 	int	pscsi_direction;
 	int	pscsi_result;
-	u32	pscsi_data_len;
+	u32	pscsi_resid;
 	void	*pscsi_buf;
+	struct request *pscsi_req;
 } pscsi_plugin_task_t;
 
 #define PDF_HAS_CHANNEL_ID	0x01
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f5d3b96..9e03a02 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -303,8 +303,8 @@ static void scsi_bi_endio(struct bio *bio, int error)
  * request can be sent to the block layer. We do not trust the scatterlist
  * sent to use, as some ULDs use that struct to only organize the pages.
  */
-static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
-			   int nsegs, unsigned bufflen, gfp_t gfp)
+int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
+		    int nsegs, unsigned bufflen, gfp_t gfp)
 {
 	struct request_queue *q = rq->q;
 	int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -379,6 +379,8 @@ free_bios:
 	return err;
 }
 
+EXPORT_SYMBOL_GPL(scsi_req_map_sg);
+
 /**
  * scsi_execute_async - insert request
  * @sdev:	scsi device
-- 
1.5.4.1



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