Re: [PATCH Linux 2.6.12-rc5-mm2 06/09] blk: update SCSI to use thenew blk_ordered
From: Jeff Garzik
Date: Sun Jun 05 2005 - 02:11:16 EST
Tejun Heo wrote:
06_blk_update_scsi_to_use_new_ordered.patch
All ordered request related stuff delegated to HLD. Midlayer
now doens't deal with ordered setting or prepare_flush
callback. sd.c updated to deal with blk_queue_ordered
setting. Currently, ordered tag isn't used as SCSI midlayer
cannot guarantee request ordering.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
drivers/scsi/hosts.c | 9 -----
drivers/scsi/scsi_lib.c | 46 --------------------------
drivers/scsi/sd.c | 79 +++++++++++++++++++--------------------------
include/scsi/scsi_driver.h | 1
include/scsi/scsi_host.h | 1
5 files changed, 34 insertions(+), 102 deletions(-)
Index: blk-fixes/drivers/scsi/sd.c
===================================================================
--- blk-fixes.orig/drivers/scsi/sd.c 2005-06-05 14:53:32.000000000 +0900
+++ blk-fixes/drivers/scsi/sd.c 2005-06-05 14:53:35.000000000 +0900
@@ -103,6 +103,7 @@ struct scsi_disk {
u8 write_prot;
unsigned WCE : 1; /* state of disk WCE bit */
unsigned RCD : 1; /* state of disk RCD bit, unused */
+ unsigned DPOFUA : 1; /* state of disk DPOFUA bit */
};
static DEFINE_IDR(sd_index_idr);
@@ -122,8 +123,7 @@ static void sd_shutdown(struct device *d
static void sd_rescan(struct device *);
static int sd_init_command(struct scsi_cmnd *);
static int sd_issue_flush(struct device *, sector_t *);
-static void sd_end_flush(request_queue_t *, struct request *);
-static int sd_prepare_flush(request_queue_t *, struct request *);
+static void sd_prepare_flush(request_queue_t *, struct request *);
static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
struct scsi_request *SRpnt, unsigned char *buffer);
@@ -138,8 +138,6 @@ static struct scsi_driver sd_template =
.rescan = sd_rescan,
.init_command = sd_init_command,
.issue_flush = sd_issue_flush,
- .prepare_flush = sd_prepare_flush,
- .end_flush = sd_end_flush,
};
/*
@@ -346,6 +344,7 @@ static int sd_init_command(struct scsi_c
if (block > 0xffffffff) {
SCpnt->cmnd[0] += READ_16 - READ_6;
+ SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
@@ -360,11 +359,12 @@ static int sd_init_command(struct scsi_c
SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
} else if ((this_count > 0xff) || (block > 0x1fffff) ||
- SCpnt->device->use_10_for_rw) {
+ SCpnt->device->use_10_for_rw || blk_fua_rq(rq)) {
This seems suspicious, like it would cause unwanted use of READ(10) for
some devices that prefer READ(6) ?
if (this_count > 0xffff)
this_count = 0xffff;
SCpnt->cmnd[0] += READ_10 - READ_6;
+ SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
@@ -739,43 +739,12 @@ static int sd_issue_flush(struct device
return sd_sync_cache(sdp);
}
-static void sd_end_flush(request_queue_t *q, struct request *flush_rq)
+static void sd_prepare_flush(request_queue_t *q, struct request *rq)
{
- struct request *rq = flush_rq->end_io_data;
- struct scsi_cmnd *cmd = rq->special;
- unsigned int bytes = rq->hard_nr_sectors << 9;
-
- if (!flush_rq->errors) {
- spin_unlock(q->queue_lock);
- scsi_io_completion(cmd, bytes, 0);
- spin_lock(q->queue_lock);
- } else if (blk_barrier_postflush(rq)) {
- spin_unlock(q->queue_lock);
- scsi_io_completion(cmd, 0, bytes);
- spin_lock(q->queue_lock);
- } else {
- /*
- * force journal abort of barriers
- */
- end_that_request_first(rq, -EOPNOTSUPP, rq->hard_nr_sectors);
- end_that_request_last(rq, -EOPNOTSUPP);
- }
-}
-
-static int sd_prepare_flush(request_queue_t *q, struct request *rq)
-{
- struct scsi_device *sdev = q->queuedata;
- struct scsi_disk *sdkp = dev_get_drvdata(&sdev->sdev_gendev);
-
- if (sdkp->WCE) {
- memset(rq->cmd, 0, sizeof(rq->cmd));
- rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
- rq->timeout = SD_TIMEOUT;
- rq->cmd[0] = SYNCHRONIZE_CACHE;
- return 1;
- }
-
- return 0;
+ memset(rq->cmd, 0, sizeof(rq->cmd));
+ rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
+ rq->timeout = SD_TIMEOUT;
+ rq->cmd[0] = SYNCHRONIZE_CACHE;
}
static void sd_rescan(struct device *dev)
@@ -1433,10 +1402,13 @@ sd_read_cache_type(struct scsi_disk *sdk
sdkp->RCD = 0;
}
+ sdkp->DPOFUA = (data.device_specific & 0x10) != 0;
+
ct = sdkp->RCD + 2*sdkp->WCE;
- printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
- diskname, types[ct]);
+ printk(KERN_NOTICE "SCSI device %s: drive cache: %s%s\n",
+ diskname, types[ct],
+ sdkp->DPOFUA ? " with forced unit access" : "");
This is IMO a bit verbose. Just " w/ FUA" might be better.
return;
}
@@ -1469,6 +1441,7 @@ static int sd_revalidate_disk(struct gen
struct scsi_device *sdp = sdkp->device;
struct scsi_request *sreq;
unsigned char *buffer;
+ unsigned ordered;
SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));
@@ -1514,7 +1487,22 @@ static int sd_revalidate_disk(struct gen
sreq, buffer);
sd_read_cache_type(sdkp, disk->disk_name, sreq, buffer);
}
-
+
+ /*
+ * We now have all cache related info, determine how we deal
+ * with ordered requests. Note that as the current SCSI
+ * dispatch function can alter request order, we cannot use
+ * QUEUE_ORDERED_TAG_* even when ordered tag is supported.
+ */
+ if (sdkp->WCE)
+ ordered = sdkp->DPOFUA
+ ? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
Certainly 'DPO and FUA' implies we have FUA, but I wonder if this test
is unnecessarily narrow.
Jeff
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/