Re: 2.6.24-rc3-mm2: Result: hostbyte=0x01driverbyte=0x00\nend_request: I/O error

From: Andrew Morton
Date: Wed Nov 28 2007 - 18:37:07 EST

On Wed, 28 Nov 2007 16:14:21 -0700
Matthew Wilcox <matthew@xxxxxx> wrote:

> On Wed, Nov 28, 2007 at 01:40:36PM -0800, Andrew Morton wrote:
> > On Wed, 28 Nov 2007 23:01:31 +0300
> > Alexey Dobriyan <adobriyan@xxxxxxxxx> wrote:
> >
> > > Reliably spams dmesg with end_request() horrors. This happens when git
> > > starts checking out linux tree to fresh ext2 partition. Disk is several
> > > month old and there were no prolems with, say, 2.6.24-rc3:
>
> Could you try reverting 6f5391c283d7fdcf24bf40786ea79061919d1e1d and see
> if the problem still exists?
>

That's not completely trivial..

I did a hand-made revert against 2.6.24-rc3-mm2 (below) but some other patch
in there causes:

drivers/scsi/scsi_lib.c: In function 'scsi_blk_pc_done':
drivers/scsi/scsi_lib.c:1251: error: 'struct scsi_cmnd' has no member named 'request_bufflen'


--- a/drivers/scsi/scsi.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/drivers/scsi/scsi.c
@@ -59,7 +59,6 @@
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
-#include <scsi/scsi_driver.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
@@ -379,8 +378,9 @@ void scsi_log_send(struct scsi_cmnd *cmd
scsi_print_command(cmd);
if (level > 3) {
printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
- " queuecommand 0x%p\n",
+ " done = 0x%p, queuecommand 0x%p\n",
scsi_sglist(cmd), scsi_bufflen(cmd),
+ cmd->done,
cmd->device->host->hostt->queuecommand);

}
@@ -667,12 +667,6 @@ void __scsi_done(struct scsi_cmnd *cmd)
blk_complete_request(rq);
}

-/* Move this to a header if it becomes more generally useful */
-static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
-{
- return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
-}
-
/**
* scsi_finish_command - cleanup and pass command back to upper layer
* @cmd: the command
@@ -685,8 +679,6 @@ void scsi_finish_command(struct scsi_cmn
{
struct scsi_device *sdev = cmd->device;
struct Scsi_Host *shost = sdev->host;
- struct scsi_driver *drv;
- unsigned int good_bytes;

scsi_device_unbusy(sdev);

@@ -712,13 +704,7 @@ void scsi_finish_command(struct scsi_cmn
"Notifying upper driver of completion "
"(result %x)\n", cmd->result));

- good_bytes = scsi_bufflen(cmd);
- if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
- drv = scsi_cmd_to_driver(cmd);
- if (drv->done)
- good_bytes = drv->done(cmd);
- }
- scsi_io_completion(cmd, good_bytes);
+ cmd->done(cmd);
}
EXPORT_SYMBOL(scsi_finish_command);

diff -puN drivers/scsi/scsi_error.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d drivers/scsi/scsi_error.c
--- a/drivers/scsi/scsi_error.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/drivers/scsi/scsi_error.c
@@ -1697,6 +1697,7 @@ scsi_reset_provider(struct scsi_device *

scmd->scsi_done = scsi_reset_provider_done_command;
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
+ scmd->done = NULL;

scmd->cmd_len = 0;

diff -puN drivers/scsi/scsi_lib.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/drivers/scsi/scsi_lib.c
@@ -944,6 +944,7 @@ void scsi_end_bidi_request(struct scsi_c

scsi_finalize_request(cmd, 1);
}
+EXPORT_SYMBOL(scsi_io_completion);

/*
* Function: scsi_io_completion()
@@ -1238,6 +1239,18 @@ static struct scsi_cmnd *scsi_get_cmd_fr
return cmd;
}

+static void scsi_blk_pc_done(struct scsi_cmnd *cmd)
+{
+ BUG_ON(!blk_pc_request(cmd->request));
+ /*
+ * This will complete the whole command with uptodate=1 so
+ * as far as the block layer is concerned the command completed
+ * successfully. Since this is a REQ_BLOCK_PC command the
+ * caller should check the request's errors value
+ */
+ scsi_io_completion(cmd, cmd->request_bufflen);
+}
+
int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
{
struct scsi_cmnd *cmd;
@@ -1285,6 +1298,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_d
cmd->transfersize = req->data_len;
cmd->allowed = req->retries;
cmd->timeout_per_command = req->timeout;
+ cmd->done = scsi_blk_pc_done;
return BLKPREP_OK;
}
EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
diff -puN drivers/scsi/scsi_priv.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d drivers/scsi/scsi_priv.h
--- a/drivers/scsi/scsi_priv.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/drivers/scsi/scsi_priv.h
@@ -68,7 +68,6 @@ extern int scsi_maybe_unblock_host(struc
extern void scsi_device_unbusy(struct scsi_device *sdev);
extern int scsi_queue_insert(struct scsi_cmnd *cmd, int reason);
extern void scsi_next_command(struct scsi_cmnd *cmd);
-extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
extern void scsi_run_host_queues(struct Scsi_Host *shost);
extern struct request_queue *scsi_alloc_queue(struct scsi_device *sdev);
extern void scsi_free_queue(struct request_queue *q);
diff -puN drivers/scsi/sd.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d drivers/scsi/sd.c
--- a/drivers/scsi/sd.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/drivers/scsi/sd.c
@@ -86,19 +86,6 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_DISK);
MODULE_ALIAS_SCSI_DEVICE(TYPE_MOD);
MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);

-static int sd_revalidate_disk(struct gendisk *);
-static int sd_probe(struct device *);
-static int sd_remove(struct device *);
-static void sd_shutdown(struct device *);
-static int sd_suspend(struct device *, pm_message_t state);
-static int sd_resume(struct device *);
-static void sd_rescan(struct device *);
-static int sd_done(struct scsi_cmnd *);
-static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
-static void scsi_disk_release(struct class_device *cdev);
-static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
-static void sd_print_result(struct scsi_disk *, int);
-
static DEFINE_IDR(sd_index_idr);
static DEFINE_SPINLOCK(sd_index_lock);

@@ -253,7 +240,6 @@ static struct scsi_driver sd_template =
.shutdown = sd_shutdown,
},
.rescan = sd_rescan,
- .done = sd_done,
};

/*
@@ -520,6 +506,12 @@ static int sd_prep_fn(struct request_que
SCpnt->timeout_per_command = timeout;

/*
+ * This is the completion routine we use. This is matched in terms
+ * of capability to this function.
+ */
+ SCpnt->done = sd_rw_intr;
+
+ /*
* This indicates that the command is ready from our end to be
* queued.
*/
@@ -898,13 +890,13 @@ static struct block_device_operations sd
};

/**
- * sd_done - bottom half handler: called when the lower level
+ * sd_rw_intr - bottom half handler: called when the lower level
* driver has completed (successfully or otherwise) a scsi command.
* @SCpnt: mid-level's per command structure.
*
* Note: potentially run from within an ISR. Must not block.
**/
-static int sd_done(struct scsi_cmnd *SCpnt)
+static void sd_rw_intr(struct scsi_cmnd * SCpnt)
{
int result = SCpnt->result;
unsigned int xfer_size = scsi_bufflen(SCpnt);
@@ -925,7 +917,7 @@ static int sd_done(struct scsi_cmnd *SCp
SCSI_LOG_HLCOMPLETE(1, scsi_print_result(SCpnt));
if (sense_valid) {
SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, SCpnt,
- "sd_done: sb[respc,sk,asc,"
+ "sd_rw_intr: sb[respc,sk,asc,"
"ascq]=%x,%x,%x,%x\n",
sshdr.response_code,
sshdr.sense_key, sshdr.asc,
@@ -997,7 +989,7 @@ static int sd_done(struct scsi_cmnd *SCp
break;
}
out:
- return good_bytes;
+ scsi_io_completion(SCpnt, good_bytes);
}

static int media_not_present(struct scsi_disk *sdkp,
diff -puN drivers/scsi/sr.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d drivers/scsi/sr.c
--- a/drivers/scsi/sr.c~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/drivers/scsi/sr.c
@@ -78,7 +78,6 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);

static int sr_probe(struct device *);
static int sr_remove(struct device *);
-static int sr_done(struct scsi_cmnd *);

static struct scsi_driver sr_template = {
.owner = THIS_MODULE,
@@ -87,7 +86,6 @@ static struct scsi_driver sr_template =
.probe = sr_probe,
.remove = sr_remove,
},
- .done = sr_done,
};

static unsigned long sr_index_bits[SR_DISKS / BITS_PER_LONG];
@@ -221,12 +219,12 @@ out:
}

/*
- * sr_done is the interrupt routine for the device driver.
+ * rw_intr is the interrupt routine for the device driver.
*
- * It will be notified on the end of a SCSI read / write, and will take one
+ * It will be notified on the end of a SCSI read / write, and will take on
* of several actions based on success or failure.
*/
-static int sr_done(struct scsi_cmnd *SCpnt)
+static void rw_intr(struct scsi_cmnd * SCpnt)
{
int result = SCpnt->result;
int this_count = scsi_bufflen(SCpnt);
@@ -299,7 +297,12 @@ static int sr_done(struct scsi_cmnd *SCp
}
}

- return good_bytes;
+ /*
+ * This calls the generic completion function, now that we know
+ * how many actual sectors finished, and how many sectors we need
+ * to say have failed.
+ */
+ scsi_io_completion(SCpnt, good_bytes);
}

static int sr_prep_fn(struct request_queue *q, struct request *rq)
@@ -434,6 +437,12 @@ static int sr_prep_fn(struct request_que
SCpnt->timeout_per_command = timeout;

/*
+ * This is the completion routine we use. This is matched in terms
+ * of capability to this function.
+ */
+ SCpnt->done = rw_intr;
+
+ /*
* This indicates that the command is ready from our end to be
* queued.
*/
diff -puN include/scsi/scsi_cmnd.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d include/scsi/scsi_cmnd.h
--- a/include/scsi/scsi_cmnd.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/include/scsi/scsi_cmnd.h
@@ -41,6 +41,7 @@ struct scsi_cmnd {
struct list_head list; /* scsi_cmnd participates in queue lists */
struct list_head eh_entry; /* entry for the host eh_cmd_q */
int eh_eflags; /* Used by error handlr */
+ void (*done) (struct scsi_cmnd *); /* Mid-level done function */

/*
* A SCSI Command is assigned a nonzero serial_number before passed
@@ -121,6 +122,7 @@ extern struct scsi_cmnd *__scsi_get_comm
extern void scsi_put_command(struct scsi_cmnd *);
extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
struct device *);
+extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
extern void scsi_finish_command(struct scsi_cmnd *cmd);
extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);

diff -puN include/scsi/scsi_driver.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d include/scsi/scsi_driver.h
--- a/include/scsi/scsi_driver.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/include/scsi/scsi_driver.h
@@ -15,7 +15,6 @@ struct scsi_driver {
struct device_driver gendrv;

void (*rescan)(struct device *);
- int (*done)(struct scsi_cmnd *);
};
#define to_scsi_driver(drv) \
container_of((drv), struct scsi_driver, gendrv)
diff -puN include/scsi/sd.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d include/scsi/sd.h
--- a/include/scsi/sd.h~revert-6f5391c283d7fdcf24bf40786ea79061919d1e1d
+++ a/include/scsi/sd.h
@@ -48,6 +48,19 @@ struct scsi_disk {
};
#define to_scsi_disk(obj) container_of(obj,struct scsi_disk,cdev)

+static int sd_revalidate_disk(struct gendisk *disk);
+static void sd_rw_intr(struct scsi_cmnd * SCpnt);
+static int sd_probe(struct device *);
+static int sd_remove(struct device *);
+static void sd_shutdown(struct device *dev);
+static int sd_suspend(struct device *dev, pm_message_t state);
+static int sd_resume(struct device *dev);
+static void sd_rescan(struct device *);
+static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
+static void scsi_disk_release(struct class_device *cdev);
+static void sd_print_sense_hdr(struct scsi_disk *, struct scsi_sense_hdr *);
+static void sd_print_result(struct scsi_disk *, int);
+
#define sd_printk(prefix, sdsk, fmt, a...) \
(sdsk)->disk ? \
sdev_printk(prefix, (sdsk)->device, "[%s] " fmt, \
_

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