ncr5380: Implement new eh_abort_handler

Introduce a new eh_abort_handler implementation. This one attempts to
follow all of the rules relating to EH handlers. There is still a known
bug: during selection, a command becomes invisible to the EH handlers
because it only appears in a pointer on the stack of a different thread.
This bug is addressed in a subsequent patch.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ondrej Zary <linux@rainbow-software.org>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index 2c9133f4c386677c1e077e053dca685481f62d53..d24852b2a7f3117ac93da94a0ec5ab996417d349 100644 (file)
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -2269,23 +2269,65 @@ static void NCR5380_dma_complete(NCR5380_instance * instance) {
 }
 #endif                         /* def REAL_DMA */
 
-/*
- * Function : int NCR5380_abort (struct scsi_cmnd *cmd)
- *
- * Purpose : abort a command
- *
- * Inputs : cmd - the scsi_cmnd to abort, code - code to set the
- *      host byte of the result field to, if zero DID_ABORTED is
- *      used.
- *
- * Returns : SUCCESS - success, FAILED on failure.
- *
- *     XXX - there is no way to abort the command that is currently
- *     connected, you have to wait for it to complete.  If this is
- *     a problem, we could implement longjmp() / setjmp(), setjmp()
- *     called where the loop started in NCR5380_main().
- *
- * Locks: host lock taken by caller
+/**
+ * list_find_cmd - test for presence of a command in a linked list
+ * @haystack: list of commands
+ * @needle: command to search for
+ */
+
+static bool list_find_cmd(struct list_head *haystack,
+                          struct scsi_cmnd *needle)
+{
+       struct NCR5380_cmd *ncmd;
+
+       list_for_each_entry(ncmd, haystack, list)
+               if (NCR5380_to_scmd(ncmd) == needle)
+                       return true;
+       return false;
+}
+
+/**
+ * list_remove_cmd - remove a command from linked list
+ * @haystack: list of commands
+ * @needle: command to remove
+ */
+
+static bool list_del_cmd(struct list_head *haystack,
+                         struct scsi_cmnd *needle)
+{
+       if (list_find_cmd(haystack, needle)) {
+               struct NCR5380_cmd *ncmd = scsi_cmd_priv(needle);
+
+               list_del(&ncmd->list);
+               return true;
+       }
+       return false;
+}
+
+/**
+ * NCR5380_abort - scsi host eh_abort_handler() method
+ * @cmd: the command to be aborted
+ *
+ * Try to abort a given command by removing it from queues and/or sending
+ * the target an abort message. This may not succeed in causing a target
+ * to abort the command. Nonetheless, the low-level driver must forget about
+ * the command because the mid-layer reclaims it and it may be re-issued.
+ *
+ * The normal path taken by a command is as follows. For EH we trace this
+ * same path to locate and abort the command.
+ *
+ * unissued -> selecting -> [unissued -> selecting ->]... connected ->
+ * [disconnected -> connected ->]...
+ * [autosense -> connected ->] done
+ *
+ * If cmd is unissued then just remove it.
+ * If cmd is disconnected, try to select the target.
+ * If cmd is connected, try to send an abort message.
+ * If cmd is waiting for autosense, give it a chance to complete but check
+ * that it isn't left connected.
+ * If cmd was not found at all then presumably it has already been completed,
+ * in which case return SUCCESS to try to avoid further EH measures.
+ * If the command has not completed yet, we must not fail to find it.
  */
 
 static int NCR5380_abort(struct scsi_cmnd *cmd)
@@ -2293,18 +2335,101 @@ static int NCR5380_abort(struct scsi_cmnd *cmd)
        struct Scsi_Host *instance = cmd->device->host;
        struct NCR5380_hostdata *hostdata = shost_priv(instance);
        unsigned long flags;
+       int result = SUCCESS;
 
        spin_lock_irqsave(&hostdata->lock, flags);
 
 #if (NDEBUG & NDEBUG_ANY)
-       scmd_printk(KERN_INFO, cmd, "aborting command\n");
+       scmd_printk(KERN_INFO, cmd, __func__);
 #endif
        NCR5380_dprint(NDEBUG_ANY, instance);
        NCR5380_dprint_phase(NDEBUG_ANY, instance);
 
+       if (list_del_cmd(&hostdata->unissued, cmd)) {
+               dsprintk(NDEBUG_ABORT, instance,
+                        "abort: removed %p from issue queue\n", cmd);
+               cmd->result = DID_ABORT << 16;
+               cmd->scsi_done(cmd); /* No tag or busy flag to worry about */
+       }
+
+       if (list_del_cmd(&hostdata->disconnected, cmd)) {
+               dsprintk(NDEBUG_ABORT, instance,
+                        "abort: removed %p from disconnected list\n", cmd);
+               cmd->result = DID_ERROR << 16;
+               if (!hostdata->connected)
+                       NCR5380_select(instance, cmd);
+               if (hostdata->connected != cmd) {
+                       complete_cmd(instance, cmd);
+                       result = FAILED;
+                       goto out;
+               }
+       }
+
+       if (hostdata->connected == cmd) {
+               dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);
+               hostdata->connected = NULL;
+               if (do_abort(instance)) {
+                       set_host_byte(cmd, DID_ERROR);
+                       complete_cmd(instance, cmd);
+                       result = FAILED;
+                       goto out;
+               }
+               set_host_byte(cmd, DID_ABORT);
+#ifdef REAL_DMA
+               hostdata->dma_len = 0;
+#endif
+               if (cmd->cmnd[0] == REQUEST_SENSE)
+                       complete_cmd(instance, cmd);
+               else {
+                       struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);
+
+                       /* Perform autosense for this command */
+                       list_add(&ncmd->list, &hostdata->autosense);
+               }
+       }
+
+       if (list_find_cmd(&hostdata->autosense, cmd)) {
+               dsprintk(NDEBUG_ABORT, instance,
+                        "abort: found %p on sense queue\n", cmd);
+               spin_unlock_irqrestore(&hostdata->lock, flags);
+               queue_work(hostdata->work_q, &hostdata->main_task);
+               msleep(1000);
+               spin_lock_irqsave(&hostdata->lock, flags);
+               if (list_del_cmd(&hostdata->autosense, cmd)) {
+                       dsprintk(NDEBUG_ABORT, instance,
+                                "abort: removed %p from sense queue\n", cmd);
+                       set_host_byte(cmd, DID_ABORT);
+                       complete_cmd(instance, cmd);
+                       goto out;
+               }
+       }
+
+       if (hostdata->connected == cmd) {
+               dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);
+               hostdata->connected = NULL;
+               if (do_abort(instance)) {
+                       set_host_byte(cmd, DID_ERROR);
+                       complete_cmd(instance, cmd);
+                       result = FAILED;
+                       goto out;
+               }
+               set_host_byte(cmd, DID_ABORT);
+#ifdef REAL_DMA
+               hostdata->dma_len = 0;
+#endif
+               complete_cmd(instance, cmd);
+       }
+
+out:
+       if (result == FAILED)
+               dsprintk(NDEBUG_ABORT, instance, "abort: failed to abort %p\n", cmd);
+       else
+               dsprintk(NDEBUG_ABORT, instance, "abort: successfully aborted %p\n", cmd);
+
+       queue_work(hostdata->work_q, &hostdata->main_task);
        spin_unlock_irqrestore(&hostdata->lock, flags);
 
-       return FAILED;
+       return result;
 }
 
 

diff --git a/drivers/scsi/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 1fcfbd82474dcf4abaf9e1daf3629649878bac0c..e3b362380a743061192ff76aa97b86f804db9850 100644 (file)
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -2480,41 +2480,168 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
 }
 
 
-/*
- * Function : int NCR5380_abort (struct scsi_cmnd *cmd)
- *
- * Purpose : abort a command
- *
- * Inputs : cmd - the scsi_cmnd to abort, code - code to set the
- *     host byte of the result field to, if zero DID_ABORTED is
- *     used.
- *
- * Returns : SUCCESS - success, FAILED on failure.
- *
- * XXX - there is no way to abort the command that is currently
- *      connected, you have to wait for it to complete.  If this is
- *      a problem, we could implement longjmp() / setjmp(), setjmp()
- *      called where the loop started in NCR5380_main().
+/**
+ * list_find_cmd - test for presence of a command in a linked list
+ * @haystack: list of commands
+ * @needle: command to search for
+ */
+
+static bool list_find_cmd(struct list_head *haystack,
+                          struct scsi_cmnd *needle)
+{
+       struct NCR5380_cmd *ncmd;
+
+       list_for_each_entry(ncmd, haystack, list)
+               if (NCR5380_to_scmd(ncmd) == needle)
+                       return true;
+       return false;
+}
+
+/**
+ * list_remove_cmd - remove a command from linked list
+ * @haystack: list of commands
+ * @needle: command to remove
  */
 
-static
-int NCR5380_abort(struct scsi_cmnd *cmd)
+static bool list_del_cmd(struct list_head *haystack,
+                         struct scsi_cmnd *needle)
+{
+       if (list_find_cmd(haystack, needle)) {
+               struct NCR5380_cmd *ncmd = scsi_cmd_priv(needle);
+
+               list_del(&ncmd->list);
+               return true;
+       }
+       return false;
+}
+
+/**
+ * NCR5380_abort - scsi host eh_abort_handler() method
+ * @cmd: the command to be aborted
+ *
+ * Try to abort a given command by removing it from queues and/or sending
+ * the target an abort message. This may not succeed in causing a target
+ * to abort the command. Nonetheless, the low-level driver must forget about
+ * the command because the mid-layer reclaims it and it may be re-issued.
+ *
+ * The normal path taken by a command is as follows. For EH we trace this
+ * same path to locate and abort the command.
+ *
+ * unissued -> selecting -> [unissued -> selecting ->]... connected ->
+ * [disconnected -> connected ->]...
+ * [autosense -> connected ->] done
+ *
+ * If cmd is unissued then just remove it.
+ * If cmd is disconnected, try to select the target.
+ * If cmd is connected, try to send an abort message.
+ * If cmd is waiting for autosense, give it a chance to complete but check
+ * that it isn't left connected.
+ * If cmd was not found at all then presumably it has already been completed,
+ * in which case return SUCCESS to try to avoid further EH measures.
+ * If the command has not completed yet, we must not fail to find it.
+ */
+
+static int NCR5380_abort(struct scsi_cmnd *cmd)
 {
        struct Scsi_Host *instance = cmd->device->host;
        struct NCR5380_hostdata *hostdata = shost_priv(instance);
        unsigned long flags;
+       int result = SUCCESS;
 
        spin_lock_irqsave(&hostdata->lock, flags);
 
 #if (NDEBUG & NDEBUG_ANY)
-       scmd_printk(KERN_INFO, cmd, "aborting command\n");
+       scmd_printk(KERN_INFO, cmd, __func__);
 #endif
        NCR5380_dprint(NDEBUG_ANY, instance);
        NCR5380_dprint_phase(NDEBUG_ANY, instance);
 
+       if (list_del_cmd(&hostdata->unissued, cmd)) {
+               dsprintk(NDEBUG_ABORT, instance,
+                        "abort: removed %p from issue queue\n", cmd);
+               cmd->result = DID_ABORT << 16;
+               cmd->scsi_done(cmd); /* No tag or busy flag to worry about */
+       }
+
+       if (list_del_cmd(&hostdata->disconnected, cmd)) {
+               dsprintk(NDEBUG_ABORT, instance,
+                        "abort: removed %p from disconnected list\n", cmd);
+               cmd->result = DID_ERROR << 16;
+               if (!hostdata->connected)
+                       NCR5380_select(instance, cmd);
+               if (hostdata->connected != cmd) {
+                       complete_cmd(instance, cmd);
+                       result = FAILED;
+                       goto out;
+               }
+       }
+
+       if (hostdata->connected == cmd) {
+               dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);
+               hostdata->connected = NULL;
+               if (do_abort(instance)) {
+                       set_host_byte(cmd, DID_ERROR);
+                       complete_cmd(instance, cmd);
+                       result = FAILED;
+                       goto out;
+               }
+               set_host_byte(cmd, DID_ABORT);
+#ifdef REAL_DMA
+               hostdata->dma_len = 0;
+#endif
+               if (cmd->cmnd[0] == REQUEST_SENSE)
+                       complete_cmd(instance, cmd);
+               else {
+                       struct NCR5380_cmd *ncmd = scsi_cmd_priv(cmd);
+
+                       /* Perform autosense for this command */
+                       list_add(&ncmd->list, &hostdata->autosense);
+               }
+       }
+
+       if (list_find_cmd(&hostdata->autosense, cmd)) {
+               dsprintk(NDEBUG_ABORT, instance,
+                        "abort: found %p on sense queue\n", cmd);
+               spin_unlock_irqrestore(&hostdata->lock, flags);
+               queue_work(hostdata->work_q, &hostdata->main_task);
+               msleep(1000);
+               spin_lock_irqsave(&hostdata->lock, flags);
+               if (list_del_cmd(&hostdata->autosense, cmd)) {
+                       dsprintk(NDEBUG_ABORT, instance,
+                                "abort: removed %p from sense queue\n", cmd);
+                       set_host_byte(cmd, DID_ABORT);
+                       complete_cmd(instance, cmd);
+                       goto out;
+               }
+       }
+
+       if (hostdata->connected == cmd) {
+               dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);
+               hostdata->connected = NULL;
+               if (do_abort(instance)) {
+                       set_host_byte(cmd, DID_ERROR);
+                       complete_cmd(instance, cmd);
+                       result = FAILED;
+                       goto out;
+               }
+               set_host_byte(cmd, DID_ABORT);
+#ifdef REAL_DMA
+               hostdata->dma_len = 0;
+#endif
+               complete_cmd(instance, cmd);
+       }
+
+out:
+       if (result == FAILED)
+               dsprintk(NDEBUG_ABORT, instance, "abort: failed to abort %p\n", cmd);
+       else
+               dsprintk(NDEBUG_ABORT, instance, "abort: successfully aborted %p\n", cmd);
+
+       queue_work(hostdata->work_q, &hostdata->main_task);
+       maybe_release_dma_irq(instance);
        spin_unlock_irqrestore(&hostdata->lock, flags);
 
-       return FAILED;
+       return result;
 }