Re: [PATCH]: Flexible timeout infrastructure

James Bottomley
2004-06-16T15:58:51Z

On Wed, 2004-06-16 at 10:48, Luben Tuikov wrote:
> Anyway, do we have a patch for *this* solution?

Here's a sketch of the implementation (without all the comments etc that
would need to be done) so people can visualise it

James

===== drivers/scsi/scsi.c 1.143 vs edited =====
--- 1.143/drivers/scsi/scsi.c 2004-04-28 11:32:09 -05:00
+++ edited/drivers/scsi/scsi.c 2004-06-16 10:47:05 -05:00
@@ -689,8 +689,6 @@
*/
void scsi_done(struct scsi_cmnd *cmd)
{
- unsigned long flags;
-
/*
* We don't have to worry about this one timing out any more.
* If we are unable to remove the timer, then the command
@@ -701,6 +699,14 @@
*/
if (!scsi_delete_timer(cmd))
return;
+ __scsi_done(cmd);
+}
+
+/* Private entry to scsi_done() to complete a command when the timer
+ * isn't running --- used by scsi_times_out */
+void __scsi_done(struct scsi_cmnd *cmd)
+{
+ unsigned long flags;

/*
* Set the serial numbers back to zero
===== drivers/scsi/scsi_error.c 1.77 vs edited =====
--- 1.77/drivers/scsi/scsi_error.c 2004-06-06 06:19:15 -05:00
+++ edited/drivers/scsi/scsi_error.c 2004-06-16 10:53:02 -05:00
@@ -162,6 +162,24 @@
void scsi_times_out(struct scsi_cmnd *scmd)
{
scsi_log_completion(scmd, TIMEOUT_ERROR);
+
+ if (scmd->device->host->hostt->eh_timed_out)
+ switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
+ case EH_HANDLED:
+ __scsi_done(scmd);
+ return;
+ case EH_RESET_TIMER:
+ /* This allows a single retry even of a command
+ * with allowed == 0 */
+ if (scmd->retries++ > scmd->allowed)
+ break;
+ scsi_add_timer(scmd, scmd->timeout_per_command,
+ scsi_times_out);
+ return;
+ case EH_NOT_HANDLED:
+ break;
+ }
+
if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
panic("Error handler thread not present at %p %p %s %d",
scmd, scmd->device->host, __FILE__, __LINE__);
===== drivers/scsi/scsi_priv.h 1.32 vs edited =====
--- 1.32/drivers/scsi/scsi_priv.h 2004-03-10 22:20:08 -06:00
+++ edited/drivers/scsi/scsi_priv.h 2004-06-16 10:45:44 -05:00
@@ -82,6 +82,7 @@
extern void scsi_init_cmd_from_req(struct scsi_cmnd *cmd,
struct scsi_request *sreq);
extern void __scsi_release_request(struct scsi_request *sreq);
+extern void __scsi_done(struct scsi_cmnd *cmd);
#ifdef CONFIG_SCSI_LOGGING
void scsi_log_send(struct scsi_cmnd *cmd);
void scsi_log_completion(struct scsi_cmnd *cmd, int disposition);
===== include/scsi/scsi_host.h 1.17 vs edited =====
--- 1.17/include/scsi/scsi_host.h 2004-06-04 11:51:31 -05:00
+++ edited/include/scsi/scsi_host.h 2004-06-16 10:36:23 -05:00
@@ -30,6 +30,12 @@
#define DISABLE_CLUSTERING 0
#define ENABLE_CLUSTERING 1

+enum scsi_eh_timer_return {
+ EH_NOT_HANDLED,
+ EH_HANDLED,
+ EH_RESET_TIMER,
+};
+

struct scsi_host_template {
struct module *module;
@@ -124,6 +130,8 @@
int (* eh_device_reset_handler)(struct scsi_cmnd *);
int (* eh_bus_reset_handler)(struct scsi_cmnd *);
int (* eh_host_reset_handler)(struct scsi_cmnd *);
+
+ enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);

/*
* Old EH handlers, no longer used. Make them warn the user of old