Messages in this thread Patch in this message | | | Date | Wed, 30 Jun 2004 19:08:10 +0200 | From | Martin Schwidefsky <> | Subject | [PATCH] s390: sclp console driver. |
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[PATCH] s390: sclp console driver.
From: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
sclp console driver changes: - Correct handling of busy and not operational states.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diffstat: drivers/s390/char/sclp.c | 69 +++++++++++++++++++++++++++++++---------------- 1 files changed, 46 insertions(+), 23 deletions(-)
diff -urN linux-2.6/drivers/s390/char/sclp.c linux-2.6-s390/drivers/s390/char/sclp.c --- linux-2.6/drivers/s390/char/sclp.c Wed Jun 16 07:19:37 2004 +++ linux-2.6-s390/drivers/s390/char/sclp.c Wed Jun 30 17:06:36 2004 @@ -52,6 +52,9 @@ /* Timer for init mask retries. */ static struct timer_list retry_timer; +/* Timer for busy retries. */ +static struct timer_list sclp_busy_timer; + static volatile unsigned long sclp_status = 0; /* some status flags */ #define SCLP_INIT 0 @@ -59,6 +62,7 @@ #define SCLP_READING 2 #define SCLP_INIT_POLL_INTERVAL 1 +#define SCLP_BUSY_POLL_INTERVAL 1 #define SCLP_COMMAND_INITIATED 0 #define SCLP_BUSY 2 @@ -93,45 +97,61 @@ */ if (cc == SCLP_NOT_OPERATIONAL) return -EIO; - /* - * We set the SCLP_RUNNING bit for cc 2 as well because if - * service_call returns cc 2 some old request is running - * that has to complete first - */ - set_bit(SCLP_RUNNING, &sclp_status); if (cc == SCLP_BUSY) return -EBUSY; return 0; } -static int +static void sclp_start_request(void) { struct sclp_req *req; int rc; unsigned long flags; - /* quick exit if sclp is already in use */ - if (test_bit(SCLP_RUNNING, &sclp_status)) - return -EBUSY; spin_lock_irqsave(&sclp_lock, flags); - /* Get first request on queue if available */ - req = NULL; - if (!list_empty(&sclp_req_queue)) + /* quick exit if sclp is already in use */ + if (test_bit(SCLP_RUNNING, &sclp_status)) { + spin_unlock_irqrestore(&sclp_lock, flags); + return; + } + /* Try to start requests from the request queue. */ + while (!list_empty(&sclp_req_queue)) { req = list_entry(sclp_req_queue.next, struct sclp_req, list); - if (req) { rc = __service_call(req->command, req->sccb); - if (rc) { - req->status = SCLP_REQ_FAILED; - list_del(&req->list); - } else + if (rc == 0) { + /* Sucessfully started request. */ req->status = SCLP_REQ_RUNNING; - } else - rc = -EINVAL; + /* Request active. Set running indication. */ + set_bit(SCLP_RUNNING, &sclp_status); + break; + } + if (rc == -EBUSY) { + /** + * SCLP is busy but no request is running. + * Try again later. + */ + if (!timer_pending(&sclp_busy_timer) || + !mod_timer(&sclp_busy_timer, + jiffies + SCLP_BUSY_POLL_INTERVAL*HZ)) { + sclp_busy_timer.function = + (void *) sclp_start_request; + sclp_busy_timer.expires = + jiffies + SCLP_BUSY_POLL_INTERVAL*HZ; + add_timer(&sclp_busy_timer); + } + break; + } + /* Request failed. */ + req->status = SCLP_REQ_FAILED; + list_del(&req->list); + if (req->callback) { + spin_unlock_irqrestore(&sclp_lock, flags); + req->callback(req, req->callback_data); + spin_lock_irqsave(&sclp_lock, flags); + } + } spin_unlock_irqrestore(&sclp_lock, flags); - if (rc == -EIO && req->callback != NULL) - req->callback(req, req->callback_data); - return rc; } static int @@ -613,6 +633,8 @@ */ do { rc = __service_call(req->command, req->sccb); + if (rc == 0) + set_bit(SCLP_RUNNING, &sclp_status); spin_unlock_irqrestore(&sclp_lock, flags); if (rc == -EIO) return -ENOSYS; @@ -685,6 +707,7 @@ ctl_set_bit(0, 9); init_timer(&retry_timer); + init_timer(&sclp_busy_timer); /* do the initial write event mask */ rc = sclp_init_mask(); if (rc == 0) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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