[S390] cio: consistent infrastructure for internal I/O requests
authorPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Mon, 7 Dec 2009 11:51:25 +0000 (12:51 +0100)
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>
Mon, 7 Dec 2009 11:51:31 +0000 (12:51 +0100)
Reduce code duplication by introducing a central infrastructure to
perform an internal I/O operation on a CCW device.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
drivers/s390/cio/Makefile
drivers/s390/cio/ccwreq.c [new file with mode: 0644]
drivers/s390/cio/device.h
drivers/s390/cio/io_sch.h

index fa4c9662f65e6c035e7d334e7b41a31b73eccfba..d033414f75997e53f22343c1d47e426e5c23fd1d 100644 (file)
@@ -3,7 +3,7 @@
 #
 
 obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o isc.o \
-       fcx.o itcw.o crw.o
+       fcx.o itcw.o crw.o ccwreq.o
 ccw_device-objs += device.o device_fsm.o device_ops.o
 ccw_device-objs += device_id.o device_pgid.o device_status.o
 obj-y += ccw_device.o cmf.o
diff --git a/drivers/s390/cio/ccwreq.c b/drivers/s390/cio/ccwreq.c
new file mode 100644 (file)
index 0000000..a6e205a
--- /dev/null
@@ -0,0 +1,327 @@
+/*
+ *  Handling of internal CCW device requests.
+ *
+ *    Copyright IBM Corp. 2009
+ *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/err.h>
+#include <asm/ccwdev.h>
+#include <asm/cio.h>
+
+#include "io_sch.h"
+#include "cio.h"
+#include "device.h"
+#include "cio_debug.h"
+
+/**
+ * lpm_adjust - adjust path mask
+ * @lpm: path mask to adjust
+ * @mask: mask of available paths
+ *
+ * Shift @lpm right until @lpm and @mask have at least one bit in common or
+ * until @lpm is zero. Return the resulting lpm.
+ */
+int lpm_adjust(int lpm, int mask)
+{
+       while (lpm && ((lpm & mask) == 0))
+               lpm >>= 1;
+       return lpm;
+}
+
+/*
+ * Adjust path mask to use next path and reset retry count. Return resulting
+ * path mask.
+ */
+static u16 ccwreq_next_path(struct ccw_device *cdev)
+{
+       struct ccw_request *req = &cdev->private->req;
+
+       req->retries    = req->maxretries;
+       req->mask       = lpm_adjust(req->mask >>= 1, req->lpm);
+
+       return req->mask;
+}
+
+/*
+ * Clean up device state and report to callback.
+ */
+static void ccwreq_stop(struct ccw_device *cdev, int rc)
+{
+       struct subchannel *sch = to_subchannel(cdev->dev.parent);
+       struct ccw_request *req = &cdev->private->req;
+
+       if (req->done)
+               return;
+       req->done = 1;
+       ccw_device_set_timeout(cdev, 0);
+       memset(&cdev->private->irb, 0, sizeof(struct irb));
+       sch->lpm = sch->schib.pmcw.pam;
+       if (rc && rc != -ENODEV && req->drc)
+               rc = req->drc;
+       req->callback(cdev, req->data, rc);
+}
+
+/*
+ * (Re-)Start the operation until retries and paths are exhausted.
+ */
+static void ccwreq_do(struct ccw_device *cdev)
+{
+       struct ccw_request *req = &cdev->private->req;
+       struct subchannel *sch = to_subchannel(cdev->dev.parent);
+       struct ccw1 *cp = req->cp;
+       int rc = -EACCES;
+
+       while (req->mask) {
+               if (req->retries-- == 0) {
+                       /* Retries exhausted, try next path. */
+                       ccwreq_next_path(cdev);
+                       continue;
+               }
+               /* Perform start function. */
+               sch->lpm = 0xff;
+               memset(&cdev->private->irb, 0, sizeof(struct irb));
+               rc = cio_start(sch, cp, req->mask);
+               if (rc == 0) {
+                       /* I/O started successfully. */
+                       ccw_device_set_timeout(cdev, req->timeout);
+                       return;
+               }
+               if (rc == -ENODEV) {
+                       /* Permanent device error. */
+                       break;
+               }
+               if (rc == -EACCES) {
+                       /* Permant path error. */
+                       ccwreq_next_path(cdev);
+                       continue;
+               }
+               /* Temporary improper status. */
+               rc = cio_clear(sch);
+               if (rc)
+                       break;
+               return;
+       }
+       ccwreq_stop(cdev, rc);
+}
+
+/**
+ * ccw_request_start - perform I/O request
+ * @cdev: ccw device
+ *
+ * Perform the I/O request specified by cdev->req.
+ */
+void ccw_request_start(struct ccw_device *cdev)
+{
+       struct ccw_request *req = &cdev->private->req;
+
+       req->mask       = 0x80;
+       req->retries    = req->maxretries;
+       req->mask       = lpm_adjust(req->mask, req->lpm);
+       req->drc        = 0;
+       req->done       = 0;
+       req->cancel     = 0;
+       if (!req->mask)
+               goto out_nopath;
+       ccwreq_do(cdev);
+       return;
+
+out_nopath:
+       ccwreq_stop(cdev, -EACCES);
+}
+
+/**
+ * ccw_request_cancel - cancel running I/O request
+ * @cdev: ccw device
+ *
+ * Cancel the I/O request specified by cdev->req. Return non-zero if request
+ * has already finished, zero otherwise.
+ */
+int ccw_request_cancel(struct ccw_device *cdev)
+{
+       struct subchannel *sch = to_subchannel(cdev->dev.parent);
+       struct ccw_request *req = &cdev->private->req;
+       int rc;
+
+       if (req->done)
+               return 1;
+       req->cancel = 1;
+       rc = cio_clear(sch);
+       if (rc)
+               ccwreq_stop(cdev, rc);
+       return 0;
+}
+
+/*
+ * Return the status of the internal I/O started on the specified ccw device.
+ * Perform BASIC SENSE if required.
+ */
+static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb)
+{
+       struct irb *irb = &cdev->private->irb;
+       struct cmd_scsw *scsw = &irb->scsw.cmd;
+
+       /* Perform BASIC SENSE if needed. */
+       if (ccw_device_accumulate_and_sense(cdev, lcirb))
+               return IO_RUNNING;
+       /* Check for halt/clear interrupt. */
+       if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC))
+               return IO_KILLED;
+       /* Check for path error. */
+       if (scsw->cc == 3 || scsw->pno)
+               return IO_PATH_ERROR;
+       /* Handle BASIC SENSE data. */
+       if (irb->esw.esw0.erw.cons) {
+               CIO_TRACE_EVENT(2, "sensedata");
+               CIO_HEX_EVENT(2, &cdev->private->dev_id,
+                             sizeof(struct ccw_dev_id));
+               CIO_HEX_EVENT(2, &cdev->private->irb.ecw, SENSE_MAX_COUNT);
+               /* Check for command reject. */
+               if (irb->ecw[0] & SNS0_CMD_REJECT)
+                       return IO_REJECTED;
+               /* Assume that unexpected SENSE data implies an error. */
+               return IO_STATUS_ERROR;
+       }
+       /* Check for channel errors. */
+       if (scsw->cstat != 0)
+               return IO_STATUS_ERROR;
+       /* Check for device errors. */
+       if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
+               return IO_STATUS_ERROR;
+       /* Check for final state. */
+       if (!(scsw->dstat & DEV_STAT_DEV_END))
+               return IO_RUNNING;
+       /* Check for other improper status. */
+       if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS))
+               return IO_STATUS_ERROR;
+       return IO_DONE;
+}
+
+/*
+ * Log ccw request status.
+ */
+static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status)
+{
+       struct ccw_request *req = &cdev->private->req;
+       struct {
+               struct ccw_dev_id dev_id;
+               u16 retries;
+               u8 lpm;
+               u8 status;
+       }  __attribute__ ((packed)) data;
+       data.dev_id     = cdev->private->dev_id;
+       data.retries    = req->retries;
+       data.lpm        = req->mask;
+       data.status     = (u8) status;
+       CIO_TRACE_EVENT(2, "reqstat");
+       CIO_HEX_EVENT(2, &data, sizeof(data));
+}
+
+/**
+ * ccw_request_handler - interrupt handler for I/O request procedure.
+ * @cdev: ccw device
+ *
+ * Handle interrupt during I/O request procedure.
+ */
+void ccw_request_handler(struct ccw_device *cdev)
+{
+       struct ccw_request *req = &cdev->private->req;
+       struct irb *irb = (struct irb *) __LC_IRB;
+       enum io_status status;
+       int rc = -EOPNOTSUPP;
+
+       /* Check status of I/O request. */
+       status = ccwreq_status(cdev, irb);
+       if (req->filter)
+               status = req->filter(cdev, req->data, irb, status);
+       if (status != IO_RUNNING)
+               ccw_device_set_timeout(cdev, 0);
+       if (status != IO_DONE && status != IO_RUNNING)
+               ccwreq_log_status(cdev, status);
+       switch (status) {
+       case IO_DONE:
+               break;
+       case IO_RUNNING:
+               return;
+       case IO_REJECTED:
+               goto err;
+       case IO_PATH_ERROR:
+               goto out_next_path;
+       case IO_STATUS_ERROR:
+               goto out_restart;
+       case IO_KILLED:
+               /* Check if request was cancelled on purpose. */
+               if (req->cancel) {
+                       rc = -EIO;
+                       goto err;
+               }
+               goto out_restart;
+       }
+       /* Check back with request initiator. */
+       if (!req->check)
+               goto out;
+       switch (req->check(cdev, req->data)) {
+       case 0:
+               break;
+       case -EAGAIN:
+               goto out_restart;
+       case -EACCES:
+               goto out_next_path;
+       default:
+               goto err;
+       }
+out:
+       ccwreq_stop(cdev, 0);
+       return;
+
+out_next_path:
+       /* Try next path and restart I/O. */
+       if (!ccwreq_next_path(cdev)) {
+               rc = -EACCES;
+               goto err;
+       }
+out_restart:
+       /* Restart. */
+       ccwreq_do(cdev);
+       return;
+err:
+       ccwreq_stop(cdev, rc);
+}
+
+
+/**
+ * ccw_request_timeout - timeout handler for I/O request procedure
+ * @cdev: ccw device
+ *
+ * Handle timeout during I/O request procedure.
+ */
+void ccw_request_timeout(struct ccw_device *cdev)
+{
+       struct subchannel *sch = to_subchannel(cdev->dev.parent);
+       struct ccw_request *req = &cdev->private->req;
+       int rc;
+
+       if (!ccwreq_next_path(cdev)) {
+               /* set the final return code for this request */
+               req->drc = -ETIME;
+       }
+       rc = cio_clear(sch);
+       if (rc)
+               goto err;
+       return;
+
+err:
+       ccwreq_stop(cdev, rc);
+}
+
+/**
+ * ccw_request_notoper - notoper handler for I/O request procedure
+ * @cdev: ccw device
+ *
+ * Handle timeout during I/O request procedure.
+ */
+void ccw_request_notoper(struct ccw_device *cdev)
+{
+       ccwreq_stop(cdev, -ENODEV);
+}
index 78662e05d317d337b8593e5ac67672a4a8da953a..f3c8a2a8c3a4ec860963ae0549e02b1e2a53a01c 100644 (file)
@@ -98,6 +98,14 @@ void ccw_device_accumulate_basic_sense(struct ccw_device *, struct irb *);
 int ccw_device_accumulate_and_sense(struct ccw_device *, struct irb *);
 int ccw_device_do_sense(struct ccw_device *, struct irb *);
 
+/* Function prototype for internal request handling. */
+int lpm_adjust(int lpm, int mask);
+void ccw_request_start(struct ccw_device *);
+int ccw_request_cancel(struct ccw_device *cdev);
+void ccw_request_handler(struct ccw_device *cdev);
+void ccw_request_timeout(struct ccw_device *cdev);
+void ccw_request_notoper(struct ccw_device *cdev);
+
 /* Function prototypes for sense id stuff. */
 void ccw_device_sense_id_start(struct ccw_device *);
 void ccw_device_sense_id_irq(struct ccw_device *, enum dev_event);
index b770e420213104d869149654d68c5cc801d849af..f9ff7683e2424c2f05d94e9926bbb4698762da76 100644 (file)
@@ -1,7 +1,10 @@
 #ifndef S390_IO_SCH_H
 #define S390_IO_SCH_H
 
+#include <linux/types.h>
 #include <asm/schid.h>
+#include <asm/ccwdev.h>
+#include "css.h"
 
 /*
  * command-mode operation request block
@@ -67,6 +70,52 @@ struct io_subchannel_private {
 
 #define MAX_CIWS 8
 
+/*
+ * Possible status values for a CCW request's I/O.
+ */
+enum io_status {
+       IO_DONE,
+       IO_RUNNING,
+       IO_STATUS_ERROR,
+       IO_PATH_ERROR,
+       IO_REJECTED,
+       IO_KILLED
+};
+
+/**
+ * ccw_request - Internal CCW request.
+ * @cp: channel program to start
+ * @timeout: maximum allowable time in jiffies between start I/O and interrupt
+ * @maxretries: number of retries per I/O operation and path
+ * @lpm: mask of paths to use
+ * @check: optional callback that determines if results are final
+ * @filter: optional callback to adjust request status based on IRB data
+ * @callback: final callback
+ * @data: user-defined pointer passed to all callbacks
+ * @mask: current path mask
+ * @retries: current number of retries
+ * @drc: delayed return code
+ * @cancel: non-zero if request was cancelled
+ * @done: non-zero if request was finished
+ */
+struct ccw_request {
+       struct ccw1 *cp;
+       unsigned long timeout;
+       u16 maxretries;
+       u8 lpm;
+       int (*check)(struct ccw_device *, void *);
+       enum io_status (*filter)(struct ccw_device *, void *, struct irb *,
+                                enum io_status);
+       void (*callback)(struct ccw_device *, void *, int);
+       void *data;
+       /* These fields are used internally. */
+       u8 mask;
+       u16 retries;
+       int drc;
+       int cancel:1;
+       int done:1;
+} __attribute__((packed));
+
 /*
  * sense-id response buffer layout
  */
@@ -99,6 +148,7 @@ struct ccw_device_private {
        unsigned long registered;
        struct ccw_dev_id dev_id;       /* device id */
        struct subchannel_id schid;     /* subchannel number */
+       struct ccw_request req;         /* internal I/O request */
        u8 imask;               /* lpm mask for SNID/SID/SPGID */
        int iretry;             /* retry counter SNID/SID/SPGID */
        struct {