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 --- drivers/scsi/NCR5380.c | 155 ++++++++++++++++++++++++++++++++++++++---- drivers/scsi/atari_NCR5380.c | 157 ++++++++++++++++++++++++++++++++++++++----- 2 files changed, 282 insertions(+), 30 deletions(-) Index: linux/drivers/scsi/atari_NCR5380.c =================================================================== --- linux.orig/drivers/scsi/atari_NCR5380.c 2015-12-06 12:31:02.000000000 +1100 +++ linux/drivers/scsi/atari_NCR5380.c 2015-12-06 12:31:05.000000000 +1100 @@ -2475,41 +2475,168 @@ static void NCR5380_reselect(struct Scsi } -/* - * Function : int NCR5380_abort (struct scsi_cmnd *cmd) +/** + * 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 * - * Purpose : abort a command + * 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. * - * 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. + * The normal path taken by a command is as follows. For EH we trace this + * same path to locate and abort the command. * - * Returns : SUCCESS - success, FAILED on failure. + * unissued -> selecting -> [unissued -> selecting ->]... connected -> + * [disconnected -> connected ->]... + * [autosense -> connected ->] done * - * 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(). + * 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) +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; } Index: linux/drivers/scsi/NCR5380.c =================================================================== --- linux.orig/drivers/scsi/NCR5380.c 2015-12-06 12:31:02.000000000 +1100 +++ linux/drivers/scsi/NCR5380.c 2015-12-06 12:31:05.000000000 +1100 @@ -2264,23 +2264,65 @@ static void NCR5380_dma_complete(NCR5380 } #endif /* def REAL_DMA */ -/* - * Function : int NCR5380_abort (struct scsi_cmnd *cmd) - * - * Purpose : abort a command +/** + * 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 * - * 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. + * 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. * - * Returns : SUCCESS - success, FAILED on failure. + * The normal path taken by a command is as follows. For EH we trace this + * same path to locate and abort the command. * - * 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(). + * unissued -> selecting -> [unissued -> selecting ->]... connected -> + * [disconnected -> connected ->]... + * [autosense -> connected ->] done * - * Locks: host lock taken by caller + * 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) @@ -2288,18 +2330,101 @@ static int NCR5380_abort(struct scsi_cmn 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; } -- 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/