/* * scsi_lib.c Copyright (C) 1999 Eric Youngdale * * SCSI queueing library. * Initial versions: Eric Youngdale (eric@andante.org). * Based upon conversations with large numbers * of people at Linux Expo. */ #include <linux/bio.h> #include <linux/bitops.h> #include <linux/blkdev.h> #include <linux/completion.h> #include <linux/kernel.h> #include <linux/mempool.h> #include <linux/slab.h> #include <linux/init.h> #include <linux/pci.h> #include <linux/delay.h> #include <linux/hardirq.h> #include <linux/scatterlist.h> #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_dbg.h> #include <scsi/scsi_device.h> #include <scsi/scsi_driver.h> #include <scsi/scsi_eh.h> #include <scsi/scsi_host.h> #include "scsi_priv.h" #include "scsi_logging.h" #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) #define SG_MEMPOOL_SIZE 2 struct scsi_host_sg_pool { size_t size; char *name; struct kmem_cache *slab; mempool_t *pool; }; #define SP(x) { x, "sgpool-" __stringify(x) } #if (SCSI_MAX_SG_SEGMENTS < 32) #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater) #endif static struct scsi_host_sg_pool scsi_sg_pools[] = { SP(8), SP(16), #if (SCSI_MAX_SG_SEGMENTS > 32) SP(32), #if (SCSI_MAX_SG_SEGMENTS > 64) SP(64), #if (SCSI_MAX_SG_SEGMENTS > 128) SP(128), #if (SCSI_MAX_SG_SEGMENTS > 256) #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX) #endif #endif #endif #endif SP(SCSI_MAX_SG_SEGMENTS) }; #undef SP struct kmem_cache *scsi_sdb_cache; static void scsi_run_queue(struct request_queue *q); /* * Function: scsi_unprep_request() * * Purpose: Remove all preparation done for a request, including its * associated scsi_cmnd, so that it can be requeued. * * Arguments: req - request to unprepare * * Lock status: Assumed that no locks are held upon entry. * * Returns: Nothing. */ static void scsi_unprep_request(struct request *req) { struct scsi_cmnd *cmd = req->special; req->cmd_flags &= ~REQ_DONTPREP; req->special = NULL; scsi_put_command(cmd); } /** * __scsi_queue_insert - private queue insertion * @cmd: The SCSI command being requeued * @reason: The reason for the requeue * @unbusy: Whether the queue should be unbusied * * This is a private queue insertion. The public interface * scsi_queue_insert() always assumes the queue should be unbusied * because it's always called before the completion. This function is * for a requeue after completion, which should only occur in this * file. */ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) { struct Scsi_Host *host = cmd->device->host; struct scsi_device *device = cmd->device; struct scsi_target *starget = scsi_target(device); struct request_queue *q = device->request_queue; unsigned long flags; SCSI_LOG_MLQUEUE(1, printk("Inserting command %p into mlqueue\n", cmd)); /* * Set the appropriate busy bit for the device/host. * * If the host/device isn't busy, assume that something actually * completed, and that we should be able to queue a command now. * * Note that the prior mid-layer assumption that any host could * always queue at least one command is now broken. The mid-layer * will implement a user specifiable stall (see * scsi_host.max_host_blocked and scsi_device.max_device_blocked) * if a command is requeued with no other commands outstanding * either for the device or for the host. */ switch (reason) { case SCSI_MLQUEUE_HOST_BUSY: host->host_blocked = host->max_host_blocked; break; case SCSI_MLQUEUE_DEVICE_BUSY: device->device_blocked = device->max_device_blocked; break; case SCSI_MLQUEUE_TARGET_BUSY: starget->target_blocked = starget->max_target_blocked; break; } /* * Decrement the counters, since these commands are no longer * active on the host/device. */ if (unbusy) scsi_device_unbusy(device); /* * Requeue this command. It will go before all other commands * that are already in the queue. * * NOTE: there is magic here about the way the queue is plugged if * we have no outstanding commands. * * Although we *don't* plug the queue, we call the request * function. The SCSI request function detects the blocked condition * and plugs the queue appropriately. */ spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, cmd->request); spin_unlock_irqrestore(q->queue_lock, flags); scsi_run_queue(q); return 0; } /* * Function: scsi_queue_insert() * * Purpose: Insert a command in the midlevel queue. * * Arguments: cmd - command that we are adding to queue. * reason - why we are inserting command to queue. * * Lock status: Assumed that lock is not held upon entry. * * Returns: Nothing. * * Notes: We do this for one of two cases. Either the host is busy * and it cannot accept any more commands for the time being, * or the device returned QUEUE_FULL and can accept no more * commands. * Notes: This could be called either from an interrupt context or a * normal process context. */ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) { return __scsi_queue_insert(cmd, reason, 1); } /** * scsi_execute - insert request and wait for the result * @sdev: scsi device * @cmd: scsi command * @data_direction: data direction * @buffer: data buffer * @bufflen: len of buffer * @sense: optional sense buffer * @timeout: request timeout in seconds * @retries: number of times to retry request * @flags: or into request flags; * @resid: optional residual length * * returns the req->errors value which is the scsi_cmnd result * field. */ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, int data_direction, void *buffer, unsigned bufflen, unsigned char *sense, int timeout, int retries, int flags, int *resid) { struct request *req; int write = (data_direction == DMA_TO_DEVICE); int ret = DRIVER_ERROR << 24; req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); if (bufflen && blk_rq_map_kern(sdev->request_queue, req, buffer, bufflen, __GFP_WAIT)) goto out; req->cmd_len = COMMAND_SIZE(cmd[0]); memcpy(req->cmd, cmd, req->cmd_len); req->sense = sense; req->sense_len = 0; req->retries = retries; req->timeout = timeout; req->cmd_type = REQ_TYPE_BLOCK_PC; req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; /* * head injection *required* here otherwise quiesce won't work */ blk_execute_rq(req->q, NULL, req, 1); /* * Some devices (USB mass-storage in particular) may transfer * garbage data together with a residue indicating that the data * is invalid. Prevent the garbage from being misinterpreted * and prevent security leaks by zeroing out the excess data. */ if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen)) memset(buffer + (bufflen - req->resid_len), 0, req->resid_len); if (resid) *resid = req->resid_len; ret = req->errors; out: blk_put_request(req); return ret; } EXPORT_SYMBOL(scsi_execute); int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, int data_direction, void *buffer, unsigned bufflen, struct scsi_sense_hdr *sshdr, int timeout, int retries, int *resid) { char *sense = NULL; int result; if (sshdr) { sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); if (!sense) return DRIVER_ERROR << 24; } result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, sense, timeout, retries, 0, resid); if (sshdr) scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); kfree(sense); return result; } EXPORT_SYMBOL(scsi_execute_req); /* * Function: scsi_init_cmd_errh() * * Purpose: Initialize cmd fields related to error handling. * * Arguments: cmd - command that is ready to be queued. * * Notes: This function has the job of initializing a number of * fields related to error handling. Typically this will * be called once for each command, as required. */ static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) { cmd->serial_number = 0; scsi_set_resid(cmd, 0); memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); if (cmd->cmd_len == 0) cmd->cmd_len = scsi_command_size(cmd->cmnd); } void scsi_device_unbusy(struct scsi_device *sdev) { struct Scsi_Host *shost = sdev->host; struct scsi_target *starget = scsi_target(sdev); unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); shost->host_busy--; starget->target_busy--; if (unlikely(scsi_host_in_recovery(shost) && (shost->host_failed || shost->host_eh_scheduled))) scsi_eh_wakeup(shost); spin_unlock(shost->host_lock); spin_lock(sdev->request_queue->queue_lock); sdev->device_busy--; spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); } /* * Called for single_lun devices on IO completion. Clear starget_sdev_user, * and call blk_run_queue for all the scsi_devices on the target - * including current_sdev first. * * Called with *no* scsi locks held. */ static void scsi_single_lun_run(struct scsi_device *current_sdev) { struct Scsi_Host *shost = current_sdev->host; struct scsi_device *sdev, *tmp; struct scsi_target *starget = scsi_target(current_sdev); unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); starget->starget_sdev_user = NULL; spin_unlock_irqrestore(shost->host_lock, flags); /* * Call blk_run_queue for all LUNs on the target, starting with * current_sdev. We race with others (to set starget_sdev_user), * but in most cases, we will be first. Ideally, each LU on the * target would get some limited time or requests on the target. */ blk_run_queue(current_sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); if (starget->starget_sdev_user) goto out; list_for_each_entry_safe(sdev, tmp, &starget->devices, same_target_siblings) { if (sdev == current_sdev) continue; if (scsi_device_get(sdev)) continue; spin_unlock_irqrestore(shost->host_lock, flags); blk_run_queue(sdev->request_queue); spin_lock_irqsave(shost->host_lock, flags); scsi_device_put(sdev); } out: spin_unlock_irqrestore(shost->host_lock, flags); } static inline int scsi_device_is_busy(struct scsi_device *sdev) { if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) return 1; return 0; } static inline int scsi_target_is_busy(struct scsi_target *starget) { return ((starget->can_queue > 0 && starget->target_busy >= starget->can_queue) || starget->target_blocked); } static inline int scsi_host_is_busy(struct Scsi_Host *shost) { if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || shost->host_blocked || shost->host_self_blocked) return 1; return 0; } /* * Function: scsi_run_queue() * * Purpose: Select a proper request queue to serve next * * Arguments: q - last request's queue * * Returns: Nothing * * Notes: The previous command was completely finished, start * a new one if possible. */ static void scsi_run_queue(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost = sdev->host; LIST_HEAD(starved_list); unsigned long flags; if (scsi_target(sdev)->single_lun) scsi_single_lun_run(sdev); spin_lock_irqsave(shost->host_lock, flags); list_splice_init(&shost->starved_list, &starved_list); while (!list_empty(&starved_list)) { int flagset; /* * As long as shost is accepting commands and we have * starved queues, call blk_run_queue. scsi_request_fn * drops the queue_lock and can add us back to the * starved_list. * * host_lock protects the starved_list and starved_entry. * scsi_request_fn must get the host_lock before checking * or modifying starved_list or starved_entry. */ if (scsi_host_is_busy(shost)) break; sdev = list_entry(starved_list.next, struct scsi_device, starved_entry); list_del_init(&sdev->starved_entry); if (scsi_target_is_busy(scsi_target(sdev))) { list_move_tail(&sdev->starved_entry, &shost->starved_list); continue; } spin_unlock(shost->host_lock); spin_lock(sdev->request_queue->queue_lock); flagset = test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && !test_bit(QUEUE_FLAG_REENTER, &sdev->request_queue->queue_flags); if (flagset) queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue); __blk_run_queue(sdev->request_queue); if (flagset) queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue); spin_unlock(sdev->request_queue->queue_lock); spin_lock(shost->host_lock); } /* put any unprocessed entries back */ list_splice(&starved_list, &shost->starved_list); spin_unlock_irqrestore(shost->host_lock, flags); blk_run_queue(q); } /* * Function: scsi_requeue_command() * * Purpose: Handle post-processing of completed commands. * * Arguments: q - queue to operate on * cmd - command that may need to be requeued. * * Returns: Nothing * * Notes: After command completion, there may be blocks left * over which weren't finished by the previous command * this can be for a number of reasons - the main one is * I/O errors in the middle of the request, in which case * we need to request the blocks that come after the bad * sector. * Notes: Upon return, cmd is a stale pointer. */ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) { struct request *req = cmd->request; unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); scsi_unprep_request(req); blk_requeue_request(q, req); spin_unlock_irqrestore(q->queue_lock, flags); scsi_run_queue(q); } void scsi_next_command(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; struct request_queue *q = sdev->request_queue; /* need to hold a reference on the device before we let go of the cmd */ get_device(&sdev->sdev_gendev); scsi_put_command(cmd); scsi_run_queue(q); /* ok to remove device now */ put_device(&sdev->sdev_gendev); } void scsi_run_host_queues(struct Scsi_Host *shost) { struct scsi_device *sdev; shost_for_each_device(sdev, shost) scsi_run_queue(sdev->request_queue); } static void __scsi_release_buffers(struct scsi_cmnd *, int); /* * Function: scsi_end_request() * * Purpose: Post-processing of completed commands (usually invoked at end * of upper level post-processing and scsi_io_completion). * * Arguments: cmd - command that is complete. * error - 0 if I/O indicates success, < 0 for I/O error. * bytes - number of bytes of completed I/O * requeue - indicates whether we should requeue leftovers. * * Lock status: Assumed that lock is not held upon entry. * * Returns: cmd if requeue required, NULL otherwise. * * Notes: This is called for block device requests in order to * mark some number of sectors as complete. * * We are guaranteeing that the request queue will be goosed * at some point during this call. * Notes: If cmd was requeued, upon return it will be a stale pointer. */ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, int bytes, int requeue) { struct request_queue *q = cmd->device->request_queue; struct request *req = cmd->request; /* * If there are blocks left over at the end, set up the command * to queue the remainder of them. */ if (blk_end_request(req, error, bytes)) { /* kill remainder if no retrys */ if (error && scsi_noretry_cmd(cmd)) blk_end_request_all(req, error); else { if (requeue) { /* * Bleah. Leftovers again. Stick the * leftovers in the front of the * queue, and goose the queue again. */ scsi_release_buffers(cmd); scsi_requeue_command(q, cmd); cmd = NULL; } return cmd; } } /* * This will goose the queue request function at the end, so we don't * need to worry about launching another command. */ __scsi_release_buffers(cmd, 0); scsi_next_command(cmd); return NULL; } static inline unsigned int scsi_sgtable_index(unsigned short nents) { unsigned int index; BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); if (nents <= 8) index = 0; else index = get_count_order(nents) - 3; return index; } static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) { struct scsi_host_sg_pool *sgp; sgp = scsi_sg_pools + scsi_sgtable_index(nents); mempool_free(sgl, sgp->pool); } static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) { struct scsi_host_sg_pool *sgp; sgp = scsi_sg_pools + scsi_sgtable_index(nents); return mempool_alloc(sgp->pool, gfp_mask); } static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, gfp_t gfp_mask) { int ret; BUG_ON(!nents); ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, gfp_mask, scsi_sg_alloc); if (unlikely(ret)) __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); return ret; } static void scsi_free_sgtable(struct scsi_data_buffer *sdb) { __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); } static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) { if (cmd->sdb.table.nents) scsi_free_sgtable(&cmd->sdb); memset(&cmd->sdb, 0, sizeof(cmd->sdb)); if (do_bidi_check && scsi_bidi_cmnd(cmd)) { struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special; scsi_free_sgtable(bidi_sdb); kmem_cache_free(scsi_sdb_cache, bidi_sdb); cmd->request->next_rq->special = NULL; } if (scsi_prot_sg_count(cmd)) scsi_free_sgtable(cmd->prot_sdb); } /* * Function: scsi_release_buffers() * * Purpose: Completion processing for block device I/O requests. * * Arguments: cmd - command that we are bailing. * * Lock status: Assumed that no lock is held upon entry. * * Returns: Nothing * * Notes: In the event that an upper level driver rejects a * command, we must release resources allocated during * the __init_io() function. Primarily this would involve * the scatter-gather table, and potentially any bounce * buffers. */ void scsi_release_buffers(struct scsi_cmnd *cmd) { __scsi_release_buffers(cmd, 1); } EXPORT_SYMBOL(scsi_release_buffers); /* * Function: scsi_io_completion() * * Purpose: Completion processing for block device I/O requests. * * Arguments: cmd - command that is finished. * * Lock status: Assumed that no lock is held upon entry. * * Returns: Nothing * * Notes: This function is matched in terms of capabilities to * the function that created the scatter-gather list. * In other words, if there are no bounce buffers * (the normal case for most drivers), we don't need * the logic to deal with cleaning up afterwards. * * We must call scsi_end_request(). This will finish off * the specified number of sectors. If we are done, the * command block will be released and the queue function * will be goosed. If we are not done then we have to * figure out what to do next: * * a) We can call scsi_requeue_command(). The request * will be unprepared and put back on the queue. Then * a new command will be created for it. This should * be used if we made forward progress, or if we want * to switch from READ(10) to READ(6) for example. * * b) We can call scsi_queue_insert(). The request will * be put back on the queue and retried using the same * command as before, possibly after a delay. * * c) We can call blk_end_request() with -EIO to fail * the remainder of the request. */ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) { int result = cmd->result; struct request_queue *q = cmd->device->request_queue; struct request *req = cmd->request; int error = 0; struct scsi_sense_hdr sshdr; int sense_valid = 0; int sense_deferred = 0; enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, ACTION_DELAYED_RETRY} action; char *description = NULL; if (result) { sense_valid = scsi_command_normalize_sense(cmd, &sshdr); if (sense_valid) sense_deferred = scsi_sense_is_deferred(&sshdr); } if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ req->errors = result; if (result) { if (sense_valid && req->sense) { /* * SG_IO wants current and deferred errors */ int len = 8 + cmd->sense_buffer[7]; if (len > SCSI_SENSE_BUFFERSIZE) len = SCSI_SENSE_BUFFERSIZE; memcpy(req->sense, cmd->sense_buffer, len); req->sense_len = len; } if (!sense_deferred) error = -EIO; } req->resid_len = scsi_get_resid(cmd); if (scsi_bidi_cmnd(cmd)) { /* * Bidi commands Must be complete as a whole, * both sides at once. */ req->next_rq->resid_len = scsi_in(cmd)->resid; scsi_release_buffers(cmd); blk_end_request_all(req, 0); scsi_next_command(cmd); return; } } BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */ /* * Next deal with any sectors which we were able to correctly * handle. */ SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, " "%d bytes done.\n", blk_rq_sectors(req), good_bytes)); /* * Recovered errors need reporting, but they're always treated * as success, so fiddle the result code here. For BLOCK_PC * we already took a copy of the original into rq->errors which * is what gets returned to the user */ if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip * print since caller wants ATA registers. Only occurs on * SCSI ATA PASS_THROUGH commands when CK_COND=1 */ if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) ; else if (!(req->cmd_flags & REQ_QUIET)) scsi_print_sense("", cmd); result = 0; /* BLOCK_PC may have set error */ error = 0; } /* * A number of bytes were successfully read. If there * are leftovers and there is some kind of error * (result != 0), retry the rest. */ if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) return; error = -EIO; if (host_byte(result) == DID_RESET) { /* Third party bus reset or reset for error recovery * reasons. Just retry the command and see what * happens. */ action = ACTION_RETRY; } else if (sense_valid && !sense_deferred) { switch (sshdr.sense_key) { case UNIT_ATTENTION: if (cmd->device->removable) { /* Detected disc change. Set a bit * and quietly refuse further access. */ cmd->device->changed = 1; description = "Media Changed"; action = ACTION_FAIL; } else { /* Must have been a power glitch, or a * bus reset. Could not have been a * media change, so we just retry the * command and see what happens. */ action = ACTION_RETRY; } break; case ILLEGAL_REQUEST: /* If we had an ILLEGAL REQUEST returned, then * we may have performed an unsupported * command. The only thing this should be * would be a ten byte read where only a six * byte read was supported. Also, on a system * where READ CAPACITY failed, we may have * read past the end of the disk. */ if ((cmd->device->use_10_for_rw && sshdr.asc == 0x20 && sshdr.ascq == 0x00) && (cmd->cmnd[0] == READ_10 || cmd->cmnd[0] == WRITE_10)) { /* This will issue a new 6-byte command. */ cmd->device->use_10_for_rw = 0; action = ACTION_REPREP; } else if (sshdr.asc == 0x10) /* DIX */ { description = "Host Data Integrity Failure"; action = ACTION_FAIL; error = -EILSEQ; } else action = ACTION_FAIL; break; case ABORTED_COMMAND: action = ACTION_FAIL; if (sshdr.asc == 0x10) { /* DIF */ description = "Target Data Integrity Failure"; error = -EILSEQ; } break; case NOT_READY: /* If the device is in the process of becoming * ready, or has a temporary blockage, retry. */ if (sshdr.asc == 0x04) { switch (sshdr.ascq) { case 0x01: /* becoming ready */ case 0x04: /* format in progress */ case 0x05: /* rebuild in progress */ case 0x06: /* recalculation in progress */ case 0x07: /* operation in progress */ case 0x08: /* Long write in progress */ case 0x09: /* self test in progress */ case 0x14: /* space allocation in progress */ action = ACTION_DELAYED_RETRY; break; default: description = "Device not ready"; action = ACTION_FAIL; break; } } else { description = "Device not ready"; action = ACTION_FAIL; } break; case VOLUME_OVERFLOW: /* See SSC3rXX or current. */ action = ACTION_FAIL; break; default: description = "Unhandled sense code"; action = ACTION_FAIL; break; } } else { description = "Unhandled error code"; action = ACTION_FAIL; } switch (action) { case ACTION_FAIL: /* Give up and fail the remainder of the request */ scsi_release_buffers(cmd); if (!(req->cmd_flags & REQ_QUIET)) { if (description) scmd_printk(KERN_INFO, cmd, "%s\n", description); scsi_print_result(cmd); if (driver_byte(result) & DRIVER_SENSE) scsi_print_sense("", cmd); scsi_print_command(cmd); } if (blk_end_request_err(req, error)) scsi_requeue_command(q, cmd); else scsi_next_command(cmd); break; case ACTION_REPREP: /* Unprep the request and put it back at the head of the queue. * A new command will be prepared and issued. */ scsi_release_buffers(cmd); scsi_requeue_command(q, cmd); break; case ACTION_RETRY: /* Retry the same command immediately */ __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); break; case ACTION_DELAYED_RETRY: /* Retry the same command after a delay */ __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); break; } } static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, gfp_t gfp_mask) { int count; /* * If sg table allocation fails, requeue request later. */ if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, gfp_mask))) { return BLKPREP_DEFER; } req->buffer = NULL; /* * Next, walk the list, and fill in the addresses and sizes of * each segment. */ count = blk_rq_map_sg(req->q, req, sdb->table.sgl); BUG_ON(count > sdb->table.nents); sdb->table.nents = count; sdb->length = blk_rq_bytes(req); return BLKPREP_OK; } /* * Function: scsi_init_io() * * Purpose: SCSI I/O initialize function. * * Arguments: cmd - Command descriptor we wish to initialize * * Returns: 0 on success * BLKPREP_DEFER if the failure is retryable * BLKPREP_KILL if the failure is fatal */ int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) { int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask); if (error) goto err_exit; if (blk_bidi_rq(cmd->request)) { struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( scsi_sdb_cache, GFP_ATOMIC); if (!bidi_sdb) { error = BLKPREP_DEFER; goto err_exit; } cmd->request->next_rq->special = bidi_sdb; error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb, GFP_ATOMIC); if (error) goto err_exit; } if (blk_integrity_rq(cmd->request)) { struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; int ivecs, count; BUG_ON(prot_sdb == NULL); ivecs = blk_rq_count_integrity_sg(cmd->request); if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { error = BLKPREP_DEFER; goto err_exit; } count = blk_rq_map_integrity_sg(cmd->request, prot_sdb->table.sgl); BUG_ON(unlikely(count > ivecs)); cmd->prot_sdb = prot_sdb; cmd->prot_sdb->table.nents = count; } return BLKPREP_OK ; err_exit: scsi_release_buffers(cmd); if (error == BLKPREP_KILL) scsi_put_command(cmd); else /* BLKPREP_DEFER */ scsi_unprep_request(cmd->request); return error; } EXPORT_SYMBOL(scsi_init_io); static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, struct request *req) { struct scsi_cmnd *cmd; if (!req->special) { cmd = scsi_get_command(sdev, GFP_ATOMIC); if (unlikely(!cmd)) return NULL; req->special = cmd; } else { cmd = req->special; } /* pull a tag out of the request if we have one */ cmd->tag = req->tag; cmd->request = req; cmd->cmnd = req->cmd; return cmd; } int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) { struct scsi_cmnd *cmd; int ret = scsi_prep_state_check(sdev, req); if (ret != BLKPREP_OK) return ret; cmd = scsi_get_cmd_from_req(sdev, req); if (unlikely(!cmd)) return BLKPREP_DEFER; /* * BLOCK_PC requests may transfer data, in which case they must * a bio attached to them. Or they might contain a SCSI command * that does not transfer data, in which case they may optionally * submit a request without an attached bio. */ if (req->bio) { int ret; BUG_ON(!req->nr_phys_segments); ret = scsi_init_io(cmd, GFP_ATOMIC); if (unlikely(ret)) return ret; } else { BUG_ON(blk_rq_bytes(req)); memset(&cmd->sdb, 0, sizeof(cmd->sdb)); req->buffer = NULL; } cmd->cmd_len = req->cmd_len; if (!blk_rq_bytes(req)) cmd->sc_data_direction = DMA_NONE; else if (rq_data_dir(req) == WRITE) cmd->sc_data_direction = DMA_TO_DEVICE; else cmd->sc_data_direction = DMA_FROM_DEVICE; cmd->transfersize = blk_rq_bytes(req); cmd->allowed = req->retries; return BLKPREP_OK; } EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); /* * Setup a REQ_TYPE_FS command. These are simple read/write request * from filesystems that still need to be translated to SCSI CDBs from * the ULD. */ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) { struct scsi_cmnd *cmd; int ret = scsi_prep_state_check(sdev, req); if (ret != BLKPREP_OK) return ret; if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh && sdev->scsi_dh_data->scsi_dh->prep_fn)) { ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); if (ret != BLKPREP_OK) return ret; } /* * Filesystem requests must transfer data. */ BUG_ON(!req->nr_phys_segments); cmd = scsi_get_cmd_from_req(sdev, req); if (unlikely(!cmd)) return BLKPREP_DEFER; memset(cmd->cmnd, 0, BLK_MAX_CDB); return scsi_init_io(cmd, GFP_ATOMIC); } EXPORT_SYMBOL(scsi_setup_fs_cmnd); int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) { int ret = BLKPREP_OK; /* * If the device is not in running state we will reject some * or all commands. */ if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { switch (sdev->sdev_state) { case SDEV_OFFLINE: /* * If the device is offline we refuse to process any * commands. The device must be brought online * before trying any recovery commands. */ sdev_printk(KERN_ERR, sdev, "rejecting I/O to offline device\n"); ret = BLKPREP_KILL; break; case SDEV_DEL: /* * If the device is fully deleted, we refuse to * process any commands as well. */ sdev_printk(KERN_ERR, sdev, "rejecting I/O to dead device\n"); ret = BLKPREP_KILL; break; case SDEV_QUIESCE: case SDEV_BLOCK: case SDEV_CREATED_BLOCK: /* * If the devices is blocked we defer normal commands. */ if (!(req->cmd_flags & REQ_PREEMPT)) ret = BLKPREP_DEFER; break; default: /* * For any other not fully online state we only allow * special commands. In particular any user initiated * command is not allowed. */ if (!(req->cmd_flags & REQ_PREEMPT)) ret = BLKPREP_KILL; break; } } return ret; } EXPORT_SYMBOL(scsi_prep_state_check); int scsi_prep_return(struct request_queue *q, struct request *req, int ret) { struct scsi_device *sdev = q->queuedata; switch (ret) { case BLKPREP_KILL: req->errors = DID_NO_CONNECT << 16; /* release the command and kill it */ if (req->special) { struct scsi_cmnd *cmd = req->special; scsi_release_buffers(cmd); scsi_put_command(cmd); req->special = NULL; } break; case BLKPREP_DEFER: /* * If we defer, the blk_peek_request() returns NULL, but the * queue must be restarted, so we plug here if no returning * command will automatically do that. */ if (sdev->device_busy == 0) blk_plug_device(q); break; default: req->cmd_flags |= REQ_DONTPREP; } return ret; } EXPORT_SYMBOL(scsi_prep_return); int scsi_prep_fn(struct request_queue *q, struct request *req) { struct scsi_device *sdev = q->queuedata; int ret = BLKPREP_KILL; if (req->cmd_type == REQ_TYPE_BLOCK_PC) ret = scsi_setup_blk_pc_cmnd(sdev, req); return scsi_prep_return(q, req, ret); } EXPORT_SYMBOL(scsi_prep_fn); /* * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else * return 0. * * Called with the queue_lock held. */ static inline int scsi_dev_queue_ready(struct request_queue *q, struct scsi_device *sdev) { if (sdev->device_busy == 0 && sdev->device_blocked) { /* * unblock after device_blocked iterates to zero */ if (--sdev->device_blocked == 0) { SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, "unblocking device at zero depth\n")); } else { blk_plug_device(q); return 0; } } if (scsi_device_is_busy(sdev)) return 0; return 1; } /* * scsi_target_queue_ready: checks if there we can send commands to target * @sdev: scsi device on starget to check. * * Called with the host lock held. */ static inline int scsi_target_queue_ready(struct Scsi_Host *shost, struct scsi_device *sdev) { struct scsi_target *starget = scsi_target(sdev); if (starget->single_lun) { if (starget->starget_sdev_user && starget->starget_sdev_user != sdev) return 0; starget->starget_sdev_user = sdev; } if (starget->target_busy == 0 && starget->target_blocked) { /* * unblock after target_blocked iterates to zero */ if (--starget->target_blocked == 0) { SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, "unblocking target at zero depth\n")); } else return 0; } if (scsi_target_is_busy(starget)) { if (list_empty(&sdev->starved_entry)) { list_add_tail(&sdev->starved_entry, &shost->starved_list); return 0; } } /* We're OK to process the command, so we can't be starved */ if (!list_empty(&sdev->starved_entry)) list_del_init(&sdev->starved_entry); return 1; } /* * scsi_host_queue_ready: if we can send requests to shost, return 1 else * return 0. We must end up running the queue again whenever 0 is * returned, else IO can hang. * * Called with host_lock held. */ static inline int scsi_host_queue_ready(struct request_queue *q, struct Scsi_Host *shost, struct scsi_device *sdev) { if (scsi_host_in_recovery(shost)) return 0; if (shost->host_busy == 0 && shost->host_blocked) { /* * unblock after host_blocked iterates to zero */ if (--shost->host_blocked == 0) { SCSI_LOG_MLQUEUE(3, printk("scsi%d unblocking host at zero depth\n", shost->host_no)); } else { return 0; } } if (scsi_host_is_busy(shost)) { if (list_empty(&sdev->starved_entry)) list_add_tail(&sdev->starved_entry, &shost->starved_list); return 0; } /* We're OK to process the command, so we can't be starved */ if (!list_empty(&sdev->starved_entry)) list_del_init(&sdev->starved_entry); return 1; } /* * Busy state exporting function for request stacking drivers. * * For efficiency, no lock is taken to check the busy state of * shost/starget/sdev, since the returned value is not guaranteed and * may be changed after request stacking drivers call the function, * regardless of taking lock or not. * * When scsi can't dispatch I/Os anymore and needs to kill I/Os * (e.g. !sdev), scsi needs to return 'not busy'. * Otherwise, request stacking drivers may hold requests forever. */ static int scsi_lld_busy(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost; struct scsi_target *starget; if (!sdev) return 0; shost = sdev->host; starget = scsi_target(sdev); if (scsi_host_in_recovery(shost) || scsi_host_is_busy(shost) || scsi_target_is_busy(starget) || scsi_device_is_busy(sdev)) return 1; return 0; } /* * Kill a request for a dead device */ static void scsi_kill_request(struct request *req, struct request_queue *q) { struct scsi_cmnd *cmd = req->special; struct scsi_device *sdev; struct scsi_target *starget; struct Scsi_Host *shost; blk_start_request(req); if (unlikely(cmd == NULL)) { printk(KERN_CRIT "impossible request in %s.\n", __func__); BUG(); } sdev = cmd->device; starget = scsi_target(sdev); shost = sdev->host; scsi_init_cmd_errh(cmd); cmd->result = DID_NO_CONNECT << 16; atomic_inc(&cmd->device->iorequest_cnt); /* * SCSI request completion path will do scsi_device_unbusy(), * bump busy counts. To bump the counters, we need to dance * with the locks as normal issue path does. */ sdev->device_busy++; spin_unlock(sdev->request_queue->queue_lock); spin_lock(shost->host_lock); shost->host_busy++; starget->target_busy++; spin_unlock(shost->host_lock); spin_lock(sdev->request_queue->queue_lock); blk_complete_request(req); } static void scsi_softirq_done(struct request *rq) { struct scsi_cmnd *cmd = rq->special; unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; int disposition; INIT_LIST_HEAD(&cmd->eh_entry); /* * Set the serial numbers back to zero */ cmd->serial_number = 0; atomic_inc(&cmd->device->iodone_cnt); if (cmd->result) atomic_inc(&cmd->device->ioerr_cnt); disposition = scsi_decide_disposition(cmd); if (disposition != SUCCESS && time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { sdev_printk(KERN_ERR, cmd->device, "timing out command, waited %lus\n", wait_for/HZ); disposition = SUCCESS; } scsi_log_completion(cmd, disposition); switch (disposition) { case SUCCESS: scsi_finish_command(cmd); break; case NEEDS_RETRY: scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); break; case ADD_TO_MLQUEUE: scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); break; default: if (!scsi_eh_scmd_add(cmd, 0)) scsi_finish_command(cmd); } } /* * Function: scsi_request_fn() * * Purpose: Main strategy routine for SCSI. * * Arguments: q - Pointer to actual queue. * * Returns: Nothing * * Lock status: IO request lock assumed to be held when called. */ static void scsi_request_fn(struct request_queue *q) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost; struct scsi_cmnd *cmd; struct request *req; if (!sdev) { printk("scsi: killing requests for dead queue\n"); while ((req = blk_peek_request(q)) != NULL) scsi_kill_request(req, q); return; } if(!get_device(&sdev->sdev_gendev)) /* We must be tearing the block queue down already */ return; /* * To start with, we keep looping until the queue is empty, or until * the host is no longer able to accept any more requests. */ shost = sdev->host; while (!blk_queue_plugged(q)) { int rtn; /* * get next queueable request. We do this early to make sure * that the request is fully prepared even if we cannot * accept it. */ req = blk_peek_request(q); if (!req || !scsi_dev_queue_ready(q, sdev)) break; if (unlikely(!scsi_device_online(sdev))) { sdev_printk(KERN_ERR, sdev, "rejecting I/O to offline device\n"); scsi_kill_request(req, q); continue; } /* * Remove the request from the request list. */ if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) blk_start_request(req); sdev->device_busy++; spin_unlock(q->queue_lock); cmd = req->special; if (unlikely(cmd == NULL)) { printk(KERN_CRIT "impossible request in %s.\n" "please mail a stack trace to " "linux-scsi@vger.kernel.org\n", __func__); blk_dump_rq_flags(req, "foo"); BUG(); } spin_lock(shost->host_lock); /* * We hit this when the driver is using a host wide * tag map. For device level tag maps the queue_depth check * in the device ready fn would prevent us from trying * to allocate a tag. Since the map is a shared host resource * we add the dev to the starved list so it eventually gets * a run when a tag is freed. */ if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { if (list_empty(&sdev->starved_entry)) list_add_tail(&sdev->starved_entry, &shost->starved_list); goto not_ready; } if (!scsi_target_queue_ready(shost, sdev)) goto not_ready; if (!scsi_host_queue_ready(q, shost, sdev)) goto not_ready; scsi_target(sdev)->target_busy++; shost->host_busy++; /* * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will * take the lock again. */ spin_unlock_irq(shost->host_lock); /* * Finally, initialize any error handling parameters, and set up * the timers for timeouts. */ scsi_init_cmd_errh(cmd); /* * Dispatch the command to the low-level driver. */ rtn = scsi_dispatch_cmd(cmd); spin_lock_irq(q->queue_lock); if(rtn) { /* we're refusing the command; because of * the way locks get dropped, we need to * check here if plugging is required */ if(sdev->device_busy == 0) blk_plug_device(q); break; } } goto out; not_ready: spin_unlock_irq(shost->host_lock); /* * lock q, handle tag, requeue req, and decrement device_busy. We * must return with queue_lock held. * * Decrementing device_busy without checking it is OK, as all such * cases (host limits or settings) should run the queue at some * later time. */ spin_lock_irq(q->queue_lock); blk_requeue_request(q, req); sdev->device_busy--; if(sdev->device_busy == 0) blk_plug_device(q); out: /* must be careful here...if we trigger the ->remove() function * we cannot be holding the q lock */ spin_unlock_irq(q->queue_lock); put_device(&sdev->sdev_gendev); spin_lock_irq(q->queue_lock); } u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) { struct device *host_dev; u64 bounce_limit = 0xffffffff; if (shost->unchecked_isa_dma) return BLK_BOUNCE_ISA; /* * Platforms with virtual-DMA translation * hardware have no practical limit. */ if (!PCI_DMA_BUS_IS_PHYS) return BLK_BOUNCE_ANY; host_dev = scsi_get_device(shost); if (host_dev && host_dev->dma_mask) bounce_limit = *host_dev->dma_mask; return bounce_limit; } EXPORT_SYMBOL(scsi_calculate_bounce_limit); struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, request_fn_proc *request_fn) { struct request_queue *q; struct device *dev = shost->shost_gendev.parent; q = blk_init_queue(request_fn, NULL); if (!q) return NULL; /* * this limit is imposed by hardware restrictions */ blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, SCSI_MAX_SG_CHAIN_SEGMENTS)); blk_queue_max_hw_sectors(q, shost->max_sectors); blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); blk_queue_segment_boundary(q, shost->dma_boundary); dma_set_seg_boundary(dev, shost->dma_boundary); blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); /* New queue, no concurrency on queue_flags */ if (!shost->use_clustering) queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q); /* * set a reasonable default alignment on word boundaries: the * host and device may alter it using * blk_queue_update_dma_alignment() later. */ blk_queue_dma_alignment(q, 0x03); return q; } EXPORT_SYMBOL(__scsi_alloc_queue); struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) { struct request_queue *q; q = __scsi_alloc_queue(sdev->host, scsi_request_fn); if (!q) return NULL; blk_queue_prep_rq(q, scsi_prep_fn); blk_queue_softirq_done(q, scsi_softirq_done); blk_queue_rq_timed_out(q, scsi_times_out); blk_queue_lld_busy(q, scsi_lld_busy); return q; } void scsi_free_queue(struct request_queue *q) { blk_cleanup_queue(q); } /* * Function: scsi_block_requests() * * Purpose: Utility function used by low-level drivers to prevent further * commands from being queued to the device. * * Arguments: shost - Host in question * * Returns: Nothing * * Lock status: No locks are assumed held. * * Notes: There is no timer nor any other means by which the requests * get unblocked other than the low-level driver calling * scsi_unblock_requests(). */ void scsi_block_requests(struct Scsi_Host *shost) { shost->host_self_blocked = 1; } EXPORT_SYMBOL(scsi_block_requests); /* * Function: scsi_unblock_requests() * * Purpose: Utility function used by low-level drivers to allow further * commands from being queued to the device. * * Arguments: shost - Host in question * * Returns: Nothing * * Lock status: No locks are assumed held. * * Notes: There is no timer nor any other means by which the requests * get unblocked other than the low-level driver calling * scsi_unblock_requests(). * * This is done as an API function so that changes to the * internals of the scsi mid-layer won't require wholesale * changes to drivers that use this feature. */ void scsi_unblock_requests(struct Scsi_Host *shost) { shost->host_self_blocked = 0; scsi_run_host_queues(shost); } EXPORT_SYMBOL(scsi_unblock_requests); int __init scsi_init_queue(void) { int i; scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", sizeof(struct scsi_data_buffer), 0, 0, NULL); if (!scsi_sdb_cache) { printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); return -ENOMEM; } for (i = 0; i < SG_MEMPOOL_NR; i++) { struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; int size = sgp->size * sizeof(struct scatterlist); sgp->slab = kmem_cache_create(sgp->name, size, 0, SLAB_HWCACHE_ALIGN, NULL); if (!sgp->slab) { printk(KERN_ERR "SCSI: can't init sg slab %s\n", sgp->name); goto cleanup_sdb; } sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, sgp->slab); if (!sgp->pool) { printk(KERN_ERR "SCSI: can't init sg mempool %s\n", sgp->name); goto cleanup_sdb; } } return 0; cleanup_sdb: for (i = 0; i < SG_MEMPOOL_NR; i++) { struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; if (sgp->pool) mempool_destroy(sgp->pool); if (sgp->slab) kmem_cache_destroy(sgp->slab); } kmem_cache_destroy(scsi_sdb_cache); return -ENOMEM; } void scsi_exit_queue(void) { int i; kmem_cache_destroy(scsi_sdb_cache); for (i = 0; i < SG_MEMPOOL_NR; i++) { struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; mempool_destroy(sgp->pool); kmem_cache_destroy(sgp->slab); } } /** * scsi_mode_select - issue a mode select * @sdev: SCSI device to be queried * @pf: Page format bit (1 == standard, 0 == vendor specific) * @sp: Save page bit (0 == don't save, 1 == save) * @modepage: mode page being requested * @buffer: request buffer (may not be smaller than eight bytes) * @len: length of request buffer. * @timeout: command timeout * @retries: number of retries before failing * @data: returns a structure abstracting the mode header data * @sshdr: place to put sense data (or NULL if no sense to be collected). * must be SCSI_SENSE_BUFFERSIZE big. * * Returns zero if successful; negative error number or scsi * status on error * */ int scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, unsigned char *buffer, int len, int timeout, int retries, struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) { unsigned char cmd[10]; unsigned char *real_buffer; int ret; memset(cmd, 0, sizeof(cmd)); cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); if (sdev->use_10_for_ms) { if (len > 65535) return -EINVAL; real_buffer = kmalloc(8 + len, GFP_KERNEL); if (!real_buffer) return -ENOMEM; memcpy(real_buffer + 8, buffer, len); len += 8; real_buffer[0] = 0; real_buffer[1] = 0; real_buffer[2] = data->medium_type; real_buffer[3] = data->device_specific; real_buffer[4] = data->longlba ? 0x01 : 0; real_buffer[5] = 0; real_buffer[6] = data->block_descriptor_length >> 8; real_buffer[7] = data->block_descriptor_length; cmd[0] = MODE_SELECT_10; cmd[7] = len >> 8; cmd[8] = len; } else { if (len > 255 || data->block_descriptor_length > 255 || data->longlba) return -EINVAL; real_buffer = kmalloc(4 + len, GFP_KERNEL); if (!real_buffer) return -ENOMEM; memcpy(real_buffer + 4, buffer, len); len += 4; real_buffer[0] = 0; real_buffer[1] = data->medium_type; real_buffer[2] = data->device_specific; real_buffer[3] = data->block_descriptor_length; cmd[0] = MODE_SELECT; cmd[4] = len; } ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, sshdr, timeout, retries, NULL); kfree(real_buffer); return ret; } EXPORT_SYMBOL_GPL(scsi_mode_select); /** * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. * @sdev: SCSI device to be queried * @dbd: set if mode sense will allow block descriptors to be returned * @modepage: mode page being requested * @buffer: request buffer (may not be smaller than eight bytes) * @len: length of request buffer. * @timeout: command timeout * @retries: number of retries before failing * @data: returns a structure abstracting the mode header data * @sshdr: place to put sense data (or NULL if no sense to be collected). * must be SCSI_SENSE_BUFFERSIZE big. * * Returns zero if unsuccessful, or the header offset (either 4 * or 8 depending on whether a six or ten byte command was * issued) if successful. */ int scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, unsigned char *buffer, int len, int timeout, int retries, struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) { unsigned char cmd[12]; int use_10_for_ms; int header_length; int result; struct scsi_sense_hdr my_sshdr; memset(data, 0, sizeof(*data)); memset(&cmd[0], 0, 12); cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ cmd[2] = modepage; /* caller might not be interested in sense, but we need it */ if (!sshdr) sshdr = &my_sshdr; retry: use_10_for_ms = sdev->use_10_for_ms; if (use_10_for_ms) { if (len < 8) len = 8; cmd[0] = MODE_SENSE_10; cmd[8] = len; header_length = 8; } else { if (len < 4) len = 4; cmd[0] = MODE_SENSE; cmd[4] = len; header_length = 4; } memset(buffer, 0, len); result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, sshdr, timeout, retries, NULL); /* This code looks awful: what it's doing is making sure an * ILLEGAL REQUEST sense return identifies the actual command * byte as the problem. MODE_SENSE commands can return * ILLEGAL REQUEST if the code page isn't supported */ if (use_10_for_ms && !scsi_status_is_good(result) && (driver_byte(result) & DRIVER_SENSE)) { if (scsi_sense_valid(sshdr)) { if ((sshdr->sense_key == ILLEGAL_REQUEST) && (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { /* * Invalid command operation code */ sdev->use_10_for_ms = 0; goto retry; } } } if(scsi_status_is_good(result)) { if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && (modepage == 6 || modepage == 8))) { /* Initio breakage? */ header_length = 0; data->length = 13; data->medium_type = 0; data->device_specific = 0; data->longlba = 0; data->block_descriptor_length = 0; } else if(use_10_for_ms) { data->length = buffer[0]*256 + buffer[1] + 2; data->medium_type = buffer[2]; data->device_specific = buffer[3]; data->longlba = buffer[4] & 0x01; data->block_descriptor_length = buffer[6]*256 + buffer[7]; } else { data->length = buffer[0] + 1; data->medium_type = buffer[1]; data->device_specific = buffer[2]; data->block_descriptor_length = buffer[3]; } data->header_length = header_length; } return result; } EXPORT_SYMBOL(scsi_mode_sense); /** * scsi_test_unit_ready - test if unit is ready * @sdev: scsi device to change the state of. * @timeout: command timeout * @retries: number of retries before failing * @sshdr_external: Optional pointer to struct scsi_sense_hdr for * returning sense. Make sure that this is cleared before passing * in. * * Returns zero if unsuccessful or an error if TUR failed. For * removable media, a return of NOT_READY or UNIT_ATTENTION is * translated to success, with the ->changed flag updated. **/ int scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, struct scsi_sense_hdr *sshdr_external) { char cmd[] = { TEST_UNIT_READY, 0, 0, 0, 0, 0, }; struct scsi_sense_hdr *sshdr; int result; if (!sshdr_external) sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); else sshdr = sshdr_external; /* try to eat the UNIT_ATTENTION if there are enough retries */ do { result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, timeout, retries, NULL); if (sdev->removable && scsi_sense_valid(sshdr) && sshdr->sense_key == UNIT_ATTENTION) sdev->changed = 1; } while (scsi_sense_valid(sshdr) && sshdr->sense_key == UNIT_ATTENTION && --retries); if (!sshdr) /* could not allocate sense buffer, so can't process it */ return result; if (sdev->removable && scsi_sense_valid(sshdr) && (sshdr->sense_key == UNIT_ATTENTION || sshdr->sense_key == NOT_READY)) { sdev->changed = 1; result = 0; } if (!sshdr_external) kfree(sshdr); return result; } EXPORT_SYMBOL(scsi_test_unit_ready); /** * scsi_device_set_state - Take the given device through the device state model. * @sdev: scsi device to change the state of. * @state: state to change to. * * Returns zero if unsuccessful or an error if the requested * transition is illegal. */ int scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) { enum scsi_device_state oldstate = sdev->sdev_state; if (state == oldstate) return 0; switch (state) { case SDEV_CREATED: switch (oldstate) { case SDEV_CREATED_BLOCK: break; default: goto illegal; } break; case SDEV_RUNNING: switch (oldstate) { case SDEV_CREATED: case SDEV_OFFLINE: case SDEV_QUIESCE: case SDEV_BLOCK: break; default: goto illegal; } break; case SDEV_QUIESCE: switch (oldstate) { case SDEV_RUNNING: case SDEV_OFFLINE: break; default: goto illegal; } break; case SDEV_OFFLINE: switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: case SDEV_QUIESCE: case SDEV_BLOCK: break; default: goto illegal; } break; case SDEV_BLOCK: switch (oldstate) { case SDEV_RUNNING: case SDEV_CREATED_BLOCK: break; default: goto illegal; } break; case SDEV_CREATED_BLOCK: switch (oldstate) { case SDEV_CREATED: break; default: goto illegal; } break; case SDEV_CANCEL: switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: case SDEV_QUIESCE: case SDEV_OFFLINE: case SDEV_BLOCK: break; default: goto illegal; } break; case SDEV_DEL: switch (oldstate) { case SDEV_CREATED: case SDEV_RUNNING: case SDEV_OFFLINE: case SDEV_CANCEL: break; default: goto illegal; } break; } sdev->sdev_state = state; return 0; illegal: SCSI_LOG_ERROR_RECOVERY(1, sdev_printk(KERN_ERR, sdev, "Illegal state transition %s->%s\n", scsi_device_state_name(oldstate), scsi_device_state_name(state)) ); return -EINVAL; } EXPORT_SYMBOL(scsi_device_set_state); /** * sdev_evt_emit - emit a single SCSI device uevent * @sdev: associated SCSI device * @evt: event to emit * * Send a single uevent (scsi_event) to the associated scsi_device. */ static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) { int idx = 0; char *envp[3]; switch (evt->evt_type) { case SDEV_EVT_MEDIA_CHANGE: envp[idx++] = "SDEV_MEDIA_CHANGE=1"; break; default: /* do nothing */ break; } envp[idx++] = NULL; kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); } /** * sdev_evt_thread - send a uevent for each scsi event * @work: work struct for scsi_device * * Dispatch queued events to their associated scsi_device kobjects * as uevents. */ void scsi_evt_thread(struct work_struct *work) { struct scsi_device *sdev; LIST_HEAD(event_list); sdev = container_of(work, struct scsi_device, event_work); while (1) { struct scsi_event *evt; struct list_head *this, *tmp; unsigned long flags; spin_lock_irqsave(&sdev->list_lock, flags); list_splice_init(&sdev->event_list, &event_list); spin_unlock_irqrestore(&sdev->list_lock, flags); if (list_empty(&event_list)) break; list_for_each_safe(this, tmp, &event_list) { evt = list_entry(this, struct scsi_event, node); list_del(&evt->node); scsi_evt_emit(sdev, evt); kfree(evt); } } } /** * sdev_evt_send - send asserted event to uevent thread * @sdev: scsi_device event occurred on * @evt: event to send * * Assert scsi device event asynchronously. */ void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) { unsigned long flags; #if 0 /* FIXME: currently this check eliminates all media change events * for polled devices. Need to update to discriminate between AN * and polled events */ if (!test_bit(evt->evt_type, sdev->supported_events)) { kfree(evt); return; } #endif spin_lock_irqsave(&sdev->list_lock, flags); list_add_tail(&evt->node, &sdev->event_list); schedule_work(&sdev->event_work); spin_unlock_irqrestore(&sdev->list_lock, flags); } EXPORT_SYMBOL_GPL(sdev_evt_send); /** * sdev_evt_alloc - allocate a new scsi event * @evt_type: type of event to allocate * @gfpflags: GFP flags for allocation * * Allocates and returns a new scsi_event. */ struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, gfp_t gfpflags) { struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); if (!evt) return NULL; evt->evt_type = evt_type; INIT_LIST_HEAD(&evt->node); /* evt_type-specific initialization, if any */ switch (evt_type) { case SDEV_EVT_MEDIA_CHANGE: default: /* do nothing */ break; } return evt; } EXPORT_SYMBOL_GPL(sdev_evt_alloc); /** * sdev_evt_send_simple - send asserted event to uevent thread * @sdev: scsi_device event occurred on * @evt_type: type of event to send * @gfpflags: GFP flags for allocation * * Assert scsi device event asynchronously, given an event type. */ void sdev_evt_send_simple(struct scsi_device *sdev, enum scsi_device_event evt_type, gfp_t gfpflags) { struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); if (!evt) { sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", evt_type); return; } sdev_evt_send(sdev, evt); } EXPORT_SYMBOL_GPL(sdev_evt_send_simple); /** * scsi_device_quiesce - Block user issued commands. * @sdev: scsi device to quiesce. * * This works by trying to transition to the SDEV_QUIESCE state * (which must be a legal transition). When the device is in this * state, only special requests will be accepted, all others will * be deferred. Since special requests may also be requeued requests, * a successful return doesn't guarantee the device will be * totally quiescent. * * Must be called with user context, may sleep. * * Returns zero if unsuccessful or an error if not. */ int scsi_device_quiesce(struct scsi_device *sdev) { int err = scsi_device_set_state(sdev, SDEV_QUIESCE); if (err) return err; scsi_run_queue(sdev->request_queue); while (sdev->device_busy) { msleep_interruptible(200); scsi_run_queue(sdev->request_queue); } return 0; } EXPORT_SYMBOL(scsi_device_quiesce); /** * scsi_device_resume - Restart user issued commands to a quiesced device. * @sdev: scsi device to resume. * * Moves the device from quiesced back to running and restarts the * queues. * * Must be called with user context, may sleep. */ void scsi_device_resume(struct scsi_device *sdev) { if(scsi_device_set_state(sdev, SDEV_RUNNING)) return; scsi_run_queue(sdev->request_queue); } EXPORT_SYMBOL(scsi_device_resume); static void device_quiesce_fn(struct scsi_device *sdev, void *data) { scsi_device_quiesce(sdev); } void scsi_target_quiesce(struct scsi_target *starget) { starget_for_each_device(starget, NULL, device_quiesce_fn); } EXPORT_SYMBOL(scsi_target_quiesce); static void device_resume_fn(struct scsi_device *sdev, void *data) { scsi_device_resume(sdev); } void scsi_target_resume(struct scsi_target *starget) { starget_for_each_device(starget, NULL, device_resume_fn); } EXPORT_SYMBOL(scsi_target_resume); /** * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state * @sdev: device to block * * Block request made by scsi lld's to temporarily stop all * scsi commands on the specified device. Called from interrupt * or normal process context. * * Returns zero if successful or error if not * * Notes: * This routine transitions the device to the SDEV_BLOCK state * (which must be a legal transition). When the device is in this * state, all commands are deferred until the scsi lld reenables * the device with scsi_device_unblock or device_block_tmo fires. * This routine assumes the host_lock is held on entry. */ int scsi_internal_device_block(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; unsigned long flags; int err = 0; err = scsi_device_set_state(sdev, SDEV_BLOCK); if (err) { err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); if (err) return err; } /* * The device has transitioned to SDEV_BLOCK. Stop the * block layer from calling the midlayer with this device's * request queue. */ spin_lock_irqsave(q->queue_lock, flags); blk_stop_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); return 0; } EXPORT_SYMBOL_GPL(scsi_internal_device_block); /** * scsi_internal_device_unblock - resume a device after a block request * @sdev: device to resume * * Called by scsi lld's or the midlayer to restart the device queue * for the previously suspended scsi device. Called from interrupt or * normal process context. * * Returns zero if successful or error if not. * * Notes: * This routine transitions the device to the SDEV_RUNNING state * (which must be a legal transition) allowing the midlayer to * goose the queue for this device. This routine assumes the * host_lock is held upon entry. */ int scsi_internal_device_unblock(struct scsi_device *sdev) { struct request_queue *q = sdev->request_queue; unsigned long flags; /* * Try to transition the scsi device to SDEV_RUNNING * and goose the device queue if successful. */ if (sdev->sdev_state == SDEV_BLOCK) sdev->sdev_state = SDEV_RUNNING; else if (sdev->sdev_state == SDEV_CREATED_BLOCK) sdev->sdev_state = SDEV_CREATED; else return -EINVAL; spin_lock_irqsave(q->queue_lock, flags); blk_start_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); return 0; } EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); static void device_block(struct scsi_device *sdev, void *data) { scsi_internal_device_block(sdev); } static int target_block(struct device *dev, void *data) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, device_block); return 0; } void scsi_target_block(struct device *dev) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, device_block); else device_for_each_child(dev, NULL, target_block); } EXPORT_SYMBOL_GPL(scsi_target_block); static void device_unblock(struct scsi_device *sdev, void *data) { scsi_internal_device_unblock(sdev); } static int target_unblock(struct device *dev, void *data) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, device_unblock); return 0; } void scsi_target_unblock(struct device *dev) { if (scsi_is_target_device(dev)) starget_for_each_device(to_scsi_target(dev), NULL, device_unblock); else device_for_each_child(dev, NULL, target_unblock); } EXPORT_SYMBOL_GPL(scsi_target_unblock); /** * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt * @sgl: scatter-gather list * @sg_count: number of segments in sg * @offset: offset in bytes into sg, on return offset into the mapped area * @len: bytes to map, on return number of bytes mapped * * Returns virtual address of the start of the mapped page */ void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, size_t *offset, size_t *len) { int i; size_t sg_len = 0, len_complete = 0; struct scatterlist *sg; struct page *page; WARN_ON(!irqs_disabled()); for_each_sg(sgl, sg, sg_count, i) { len_complete = sg_len; /* Complete sg-entries */ sg_len += sg->length; if (sg_len > *offset) break; } if (unlikely(i == sg_count)) { printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " "elements %d\n", __func__, sg_len, *offset, sg_count); WARN_ON(1); return NULL; } /* Offset starting from the beginning of first page in this sg-entry */ *offset = *offset - len_complete + sg->offset; /* Assumption: contiguous pages can be accessed as "page + i" */ page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); *offset &= ~PAGE_MASK; /* Bytes in this sg-entry from *offset to the end of the page */ sg_len = PAGE_SIZE - *offset; if (*len > sg_len) *len = sg_len; return kmap_atomic(page, KM_BIO_SRC_IRQ); } EXPORT_SYMBOL(scsi_kmap_atomic_sg); /** * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg * @virt: virtual address to be unmapped */ void scsi_kunmap_atomic_sg(void *virt) { kunmap_atomic(virt, KM_BIO_SRC_IRQ); } EXPORT_SYMBOL(scsi_kunmap_atomic_sg);