[dm-devel] [PATCH RFT/RFC 3/4] convert dm emc
Mike Christie
michaelc at cs.wisc.edu
Fri Sep 30 19:42:20 UTC 2005
dm emc does not have to do very much now :)
I am still trying to figure out the best way
to evaluate the sense but allow a hw handler to
overide the decision. dm-emc just fails
on all errors so I did not put much effort into
it for the moment.
Signed-off-by: Mike Christie <michaelc at cs.wisc.edu>
diff --git a/drivers/md/dm-emc.c b/drivers/md/dm-emc.c
--- a/drivers/md/dm-emc.c
+++ b/drivers/md/dm-emc.c
@@ -1,6 +1,7 @@
/*
* Copyright (C) 2004 SUSE LINUX Products GmbH. All rights reserved.
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2005 Mike Christie, All rights reserved.
*
* This file is released under the GPL.
*
@@ -21,202 +22,85 @@ struct emc_handler {
/* Whether or not to honor SCSI reservations when initiating a
* switch-over. Default: Don't. */
unsigned hr;
-
- unsigned char sense[SCSI_SENSE_BUFFERSIZE];
};
#define TRESPASS_PAGE 0x22
#define EMC_FAILOVER_TIMEOUT (60 * HZ)
-/* Code borrowed from dm-lsi-rdac by Mike Christie */
+static unsigned char emc_long_trespass[] = {
+ 0, 0, 0, 0,
+ TRESPASS_PAGE, /* Page code */
+ 0x09, /* Page length - 2 */
+ 0x81, /* Trespass code + Honor reservation bit */
+ 0xff, 0xff, /* Trespass target */
+ 0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
+};
-static inline void free_bio(struct bio *bio)
-{
- __free_page(bio->bi_io_vec[0].bv_page);
- bio_put(bio);
-}
+static unsigned char emc_long_trespass_hr[] = {
+ 0, 0, 0, 0,
+ TRESPASS_PAGE, /* Page code */
+ 0x09, /* Page length - 2 */
+ 0x01, /* Trespass code + Honor reservation bit */
+ 0xff, 0xff, /* Trespass target */
+ 0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
+};
-static int emc_endio(struct bio *bio, unsigned int bytes_done, int error)
-{
- struct path *path = bio->bi_private;
+static unsigned char emc_short_trespass[] = {
+ 0, 0, 0, 0,
+ TRESPASS_PAGE, /* Page code */
+ 0x02, /* Page length - 2 */
+ 0x81, /* Trespass code + Honor reservation bit */
+ 0xff, /* Trespass target */
+};
- if (bio->bi_size)
- return 1;
+static unsigned char emc_short_trespass_hr[] = {
+ 0, 0, 0, 0,
+ TRESPASS_PAGE, /* Page code */
+ 0x02, /* Page length - 2 */
+ 0x01, /* Trespass code + Honor reservation bit */
+ 0xff, /* Trespass target */
+};
+
+/* Code borrowed from dm-lsi-rdac by Mike Christie */
+static unsigned emc_rq_error(struct path *path, int result,
+ struct scsi_sense_hdr *sense)
+{
/* We also need to look at the sense keys here whether or not to
* switch to the next PG etc.
*
* For now simple logic: either it works or it doesn't.
*/
- if (error)
- dm_pg_init_complete(path, MP_FAIL_PATH);
- else
- dm_pg_init_complete(path, 0);
-
- /* request is freed in block layer */
- free_bio(bio);
-
- return 0;
-}
-
-static struct bio *get_failover_bio(struct path *path, unsigned data_size)
-{
- struct bio *bio;
- struct page *page;
-
- bio = bio_alloc(GFP_ATOMIC, 1);
- if (!bio) {
- DMERR("dm-emc: get_failover_bio: bio_alloc() failed.");
- return NULL;
- }
-
- bio->bi_rw |= (1 << BIO_RW);
- bio->bi_bdev = path->dev->bdev;
- bio->bi_sector = 0;
- bio->bi_private = path;
- bio->bi_end_io = emc_endio;
-
- page = alloc_page(GFP_ATOMIC);
- if (!page) {
- DMERR("dm-emc: get_failover_bio: alloc_page() failed.");
- bio_put(bio);
- return NULL;
- }
-
- if (bio_add_page(bio, page, data_size, 0) != data_size) {
- DMERR("dm-emc: get_failover_bio: alloc_page() failed.");
- __free_page(page);
- bio_put(bio);
- return NULL;
- }
-
- return bio;
-}
-
-static struct request *get_failover_req(struct emc_handler *h,
- struct bio *bio, struct path *path)
-{
- struct request *rq;
- struct block_device *bdev = bio->bi_bdev;
- struct request_queue *q = bdev_get_queue(bdev);
-
- /* FIXME: Figure out why it fails with GFP_ATOMIC. */
- rq = blk_get_request(q, WRITE, __GFP_WAIT);
- if (!rq) {
- DMERR("dm-emc: get_failover_req: blk_get_request failed");
- return NULL;
- }
-
- rq->bio = rq->biotail = bio;
- blk_rq_bio_prep(q, rq, bio);
-
- rq->rq_disk = bdev->bd_contains->bd_disk;
-
- /* bio backed don't set data */
- rq->buffer = rq->data = NULL;
- /* rq data_len used for pc cmd's request_bufflen */
- rq->data_len = bio->bi_size;
-
- rq->sense = h->sense;
- memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
- rq->sense_len = 0;
-
- memset(&rq->cmd, 0, BLK_MAX_CDB);
-
- rq->timeout = EMC_FAILOVER_TIMEOUT;
- rq->flags |= (REQ_BLOCK_PC | REQ_FAILFAST | REQ_NOMERGE);
-
- return rq;
-}
-
-static struct request *emc_trespass_get(struct emc_handler *h,
- struct path *path)
-{
- struct bio *bio;
- struct request *rq;
- unsigned char *page22;
- unsigned char long_trespass_pg[] = {
- 0, 0, 0, 0,
- TRESPASS_PAGE, /* Page code */
- 0x09, /* Page length - 2 */
- h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
- 0xff, 0xff, /* Trespass target */
- 0, 0, 0, 0, 0, 0 /* Reserved bytes / unknown */
- };
- unsigned char short_trespass_pg[] = {
- 0, 0, 0, 0,
- TRESPASS_PAGE, /* Page code */
- 0x02, /* Page length - 2 */
- h->hr ? 0x01 : 0x81, /* Trespass code + Honor reservation bit */
- 0xff, /* Trespass target */
- };
- unsigned data_size = h->short_trespass ? sizeof(short_trespass_pg) :
- sizeof(long_trespass_pg);
-
- /* get bio backing */
- if (data_size > PAGE_SIZE)
- /* this should never happen */
- return NULL;
-
- bio = get_failover_bio(path, data_size);
- if (!bio) {
- DMERR("dm-emc: emc_trespass_get: no bio");
- return NULL;
- }
-
- page22 = (unsigned char *)bio_data(bio);
- memset(page22, 0, data_size);
-
- memcpy(page22, h->short_trespass ?
- short_trespass_pg : long_trespass_pg, data_size);
-
- /* get request for block layer packet command */
- rq = get_failover_req(h, bio, path);
- if (!rq) {
- DMERR("dm-emc: emc_trespass_get: no rq");
- free_bio(bio);
- return NULL;
- }
-
- /* Prepare the command. */
- rq->cmd[0] = MODE_SELECT;
- rq->cmd[1] = 0x10;
- rq->cmd[4] = data_size;
- rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
-
- return rq;
+ return result ? MP_FAIL_PATH : 0;
}
static void emc_pg_init(struct hw_handler *hwh, unsigned bypassed,
struct path *path)
{
- struct request *rq;
- struct request_queue *q = bdev_get_queue(path->dev->bdev);
+ struct emc_handler *h = hwh->context;
+ unsigned char *page22;
+ unsigned data_size;
+ unsigned char cmd[MAX_COMMAND_SIZE];
- /*
- * We can either blindly init the pg (then look at the sense),
- * or we can send some commands to get the state here (then
- * possibly send the fo cmnd), or we can also have the
- * initial state passed into us and then get an update here.
- */
- if (!q) {
- DMINFO("dm-emc: emc_pg_init: no queue");
- goto fail_path;
+ if (h->short_trespass) {
+ page22 = h->hr ? emc_short_trespass_hr : emc_short_trespass;
+ data_size = sizeof(emc_short_trespass);
+ } else {
+ page22 = h->hr ? emc_long_trespass_hr : emc_long_trespass;
+ data_size = sizeof(emc_long_trespass);
}
- /* FIXME: The request should be pre-allocated. */
- rq = emc_trespass_get(hwh->context, path);
- if (!rq) {
- DMERR("dm-emc: emc_pg_init: no rq");
- goto fail_path;
- }
+ /* Prepare the command. */
+ memset(cmd, 0, MAX_COMMAND_SIZE);
+ cmd[0] = MODE_SELECT;
+ cmd[1] = 0x10;
+ cmd[4] = data_size;
DMINFO("dm-emc: emc_pg_init: sending switch-over command");
- elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 1);
- return;
-fail_path:
- dm_pg_init_complete(path, MP_FAIL_PATH);
+ if (dm_scsi_execute_rq(hwh, path, cmd, DMA_TO_DEVICE, page22, data_size,
+ EMC_FAILOVER_TIMEOUT, __GFP_WAIT))
+ dm_pg_init_complete(path, MP_FAIL_PATH);
}
static struct emc_handler *alloc_emc_handler(void)
@@ -263,6 +147,11 @@ static int emc_create(struct hw_handler
hwh->context = h;
+ if (dm_scsi_init_context_pool(hwh)) {
+ kfree(h);
+ return -ENOMEM;
+ }
+
if ((h->short_trespass = short_trespass))
DMWARN("dm-emc: short trespass command will be send");
else
@@ -280,6 +169,7 @@ static void emc_destroy(struct hw_handle
{
struct emc_handler *h = (struct emc_handler *) hwh->context;
+ dm_scsi_destroy_context_pool(hwh);
kfree(h);
hwh->context = NULL;
}
@@ -329,6 +219,7 @@ static struct hw_handler_type emc_hwh =
.destroy = emc_destroy,
.pg_init = emc_pg_init,
.error = emc_error,
+ .rq_error = emc_rq_error,
};
static int __init dm_emc_init(void)
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