Subject: scsi_dh: scsi handling of REQ_LB_OP_TRANSITION
From: Mike Christie <michaelc@xxxxxxxxxxx>
This patch adds a scsi handler for REQ_LB_OP_TRANSITION commands.
Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx>
---
---
drivers/scsi/scsi_lib.c | 113 111 + 2 - 0 !
include/scsi/scsi_cmnd.h | 1 1 + 0 - 0 !
include/scsi/scsi_device.h | 13 13 + 0 - 0 !
3 files changed, 125 insertions(+), 2 deletions(-)
Index: linux-2.6.24-rc8/drivers/scsi/scsi_lib.c
===================================================================
--- linux-2.6.24-rc8.orig/drivers/scsi/scsi_lib.c
+++ linux-2.6.24-rc8/drivers/scsi/scsi_lib.c
@@ -1163,6 +1163,38 @@ static struct scsi_cmnd *scsi_get_cmd_fr
return cmd;
}
+static int scsi_setup_blk_linux_cmnd(struct scsi_device *sdev,
+ struct request *rq)
+{
+ if (!get_device(&sdev->sdev_gendev)) {
+ rq->errors = BLKERR_DEV_OFFLINED;
+ return BLKPREP_KILL;
+ }
+
+ switch (rq->cmd[0]) {
+ case REQ_LB_OP_TRANSITION:
+ if (!sdev->sdev_dh || !sdev->sdev_dh->transition) {
+ /* set REQ_LB_OP_TRANSITION specific error */
+ rq->errors = BLKERR_NOSYS;
+ goto kill;
+ }
+ if (!try_module_get(sdev->sdev_dh->module)) {
+ rq->errors = BLKERR_DEV_OFFLINED;
+ goto kill;
+ }
+
+ break;
+ default:
+ rq->errors = BLKERR_INVALID_IO;
+ goto kill;
+ }
+ return BLKPREP_OK;
+
+kill:
+ put_device(&sdev->sdev_gendev);
+ return BLKPREP_KILL;
+}
+
int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
{
struct scsi_cmnd *cmd;
@@ -1332,6 +1364,8 @@ int scsi_prep_fn(struct request_queue *q
if (req->cmd_type == REQ_TYPE_BLOCK_PC)
ret = scsi_setup_blk_pc_cmnd(sdev, req);
+ else if (req->cmd_type == REQ_TYPE_LINUX_BLOCK)
+ ret = scsi_setup_blk_linux_cmnd(sdev, req);
return scsi_prep_return(q, req, ret);
}
EXPORT_SYMBOL(scsi_prep_fn);
@@ -1445,9 +1479,24 @@ static void scsi_kill_request(struct req
static void scsi_softirq_done(struct request *rq)
{
struct scsi_cmnd *cmd = rq->completion_data;
- unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
int disposition;
+ struct request_queue *q;
+ unsigned long wait_for, flags;
+ if (blk_linux_request(rq)) {
+ q = rq->q;
+ spin_lock_irqsave(q->queue_lock, flags);
+ /*
+ * we always return 1 and the caller should
+ * check rq->errors for the complete status
+ */
+ end_that_request_last(rq, 1);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ return;
+ }
+
+
+ wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
INIT_LIST_HEAD(&cmd->eh_entry);
disposition = scsi_decide_disposition(cmd);
@@ -1477,6 +1526,50 @@ static void scsi_softirq_done(struct req
}
}
+/**
+ * scsi_blk_linux_cmd_done - Complete a REQ_TYPE_LINUX_BLOCK request.
+ * @req: REQ_TYPE_LINUX_BLOCK request being processed
+ * @err: return value
+ *
+ * This function should be called by the REQ_TYPE_LINUX_BLOCK handler
+ * to return the request to its caller. This function queues the
+ * the completion to the blk softirq so the queue lock does not have
+ * to be held here.
+ */
+void scsi_blk_linux_cmd_done(struct request *rq, int err)
+{
+ struct scsi_device *sdev = rq->q->queuedata;
+
+ switch (rq->cmd[0]) {
+ case REQ_LB_OP_TRANSITION:
+ module_put(sdev->sdev_dh->module);
+ break;
+ }
+
+ put_device(&sdev->sdev_gendev);
+ rq->errors = err;
+ rq->completion_data = NULL;
+ blk_complete_request(rq);
+}
+EXPORT_SYMBOL_GPL(scsi_blk_linux_cmd_done);
+
+static void scsi_execute_blk_linux_cmd(struct request *rq)
+{
+ struct request_queue *q = rq->q;
+ struct scsi_device *sdev = q->queuedata;
+
+ switch (rq->cmd[0]) {
+ case REQ_LB_OP_TRANSITION:
+ spin_unlock_irq(q->queue_lock);
+ sdev->sdev_dh->transition(rq);
+ spin_lock_irq(q->queue_lock);
+ break;
+ default:
+ /* should have checked in scsi_prep_fn already */
+ BUG();
+ }
+}
+
/*
* Function: scsi_request_fn()
*
@@ -1519,7 +1612,23 @@ static void scsi_request_fn(struct reque
* accept it.
*/
req = elv_next_request(q);
- if (!req || !scsi_dev_queue_ready(q, sdev))
+ if (!req)
+ break;
+
+ /*
+ * We do not account for linux blk req in the device
+ * or host busy accounting because it is not necessarily
+ * a scsi command that is sent to some object. The lower
+ * level can translate it into a request/scsi_cmnd, if
+ * necessary, and then queue that up using REQ_TYPE_BLOCK_PC.
+ */
+ if (blk_linux_request(req)) {
+ blkdev_dequeue_request(req);
+ scsi_execute_blk_linux_cmd(req);
+ continue;
+ }
+
+ if (!scsi_dev_queue_ready(q, sdev))
break;
if (unlikely(!scsi_device_online(sdev))) {
Index: linux-2.6.24-rc8/include/scsi/scsi_cmnd.h
===================================================================
--- linux-2.6.24-rc8.orig/include/scsi/scsi_cmnd.h
+++ linux-2.6.24-rc8/include/scsi/scsi_cmnd.h
@@ -123,6 +123,7 @@ extern void __scsi_put_command(struct Sc
struct device *);
extern void scsi_finish_command(struct scsi_cmnd *cmd);
extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
+extern void scsi_blk_linux_cmd_done(struct request *req, int err);
extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
size_t *offset, size_t *len);
Index: linux-2.6.24-rc8/include/scsi/scsi_device.h
===================================================================
--- linux-2.6.24-rc8.orig/include/scsi/scsi_device.h
+++ linux-2.6.24-rc8/include/scsi/scsi_device.h
@@ -160,9 +160,22 @@ struct scsi_device {
struct execute_work ew; /* used to get process context on put */
+ struct scsi_device_handler *sdev_dh;
+ void *sdev_dh_data;
enum scsi_device_state sdev_state;
unsigned long sdev_data[0];
} __attribute__((aligned(sizeof(unsigned long))));
+
+struct scsi_device_handler {
+ struct module *module;
+ const char *name;
+
+ struct notifier_block nb;
+
+ int (*check_sense)(struct scsi_device *, struct scsi_sense_hdr *);
+ void (*transition)(struct request *);
+};
+
#define to_scsi_device(d) \
container_of(d, struct scsi_device, sdev_gendev)
#define class_to_sdev(d) \
--
----------------------------------------------------------------------
Chandra Seetharaman | Be careful what you choose....
- sekharan@xxxxxxxxxx | .......you may get it.
----------------------------------------------------------------------
-
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