diff options
| -rw-r--r-- | drivers/scsi/st.c | 150 | ||||
| -rw-r--r-- | drivers/scsi/st.h | 3 |
2 files changed, 123 insertions, 30 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 0291a8f..47a5698 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -17,7 +17,7 @@ Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support */ -static char *verstr = "20050501"; +static char *verstr = "20050802"; #include <linux/module.h> @@ -219,6 +219,12 @@ static int switch_partition(struct scsi_tape *); static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long); +static void scsi_tape_release(struct kref *); + +#define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref) + +static DECLARE_MUTEX(st_ref_sem); + #include "osst_detect.h" #ifndef SIGS_FROM_OSST @@ -230,6 +236,46 @@ static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long); {"OnStream", "FW-", "", "osst"} #endif +static struct scsi_tape *scsi_tape_get(int dev) +{ + struct scsi_tape *STp = NULL; + + down(&st_ref_sem); + write_lock(&st_dev_arr_lock); + + if (dev < st_dev_max && scsi_tapes != NULL) + STp = scsi_tapes[dev]; + if (!STp) goto out; + + kref_get(&STp->kref); + + if (!STp->device) + goto out_put; + + if (scsi_device_get(STp->device)) + goto out_put; + + goto out; + +out_put: + kref_put(&STp->kref, scsi_tape_release); + STp = NULL; +out: + write_unlock(&st_dev_arr_lock); + up(&st_ref_sem); + return STp; +} + +static void scsi_tape_put(struct scsi_tape *STp) +{ + struct scsi_device *sdev = STp->device; + + down(&st_ref_sem); + kref_put(&STp->kref, scsi_tape_release); + scsi_device_put(sdev); + up(&st_ref_sem); +} + struct st_reject_data { char *vendor; char *model; @@ -311,7 +357,7 @@ static int st_chk_result(struct scsi_tape *STp, struct scsi_request * SRpnt) return 0; cmdstatp = &STp->buffer->cmdstat; - st_analyze_sense(STp->buffer->last_SRpnt, cmdstatp); + st_analyze_sense(SRpnt, cmdstatp); if (cmdstatp->have_sense) scode = STp->buffer->cmdstat.sense_hdr.sense_key; @@ -399,10 +445,10 @@ static void st_sleep_done(struct scsi_cmnd * SCpnt) (STp->buffer)->cmdstat.midlevel_result = SCpnt->result; SCpnt->request->rq_status = RQ_SCSI_DONE; - (STp->buffer)->last_SRpnt = SCpnt->sc_request; DEB( STp->write_pending = 0; ) - complete(SCpnt->request->waiting); + if (SCpnt->request->waiting) + complete(SCpnt->request->waiting); } /* Do the scsi command. Waits until command performed if do_wait is true. @@ -412,8 +458,20 @@ static struct scsi_request * st_do_scsi(struct scsi_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd, int bytes, int direction, int timeout, int retries, int do_wait) { + struct completion *waiting; unsigned char *bp; + /* if async, make sure there's no command outstanding */ + if (!do_wait && ((STp->buffer)->last_SRpnt)) { + printk(KERN_ERR "%s: Async command already active.\n", + tape_name(STp)); + if (signal_pending(current)) + (STp->buffer)->syscall_result = (-EINTR); + else + (STp->buffer)->syscall_result = (-EBUSY); + return NULL; + } + if (SRpnt == NULL) { SRpnt = scsi_allocate_request(STp->device, GFP_ATOMIC); if (SRpnt == NULL) { @@ -427,7 +485,13 @@ st_do_scsi(struct scsi_request * SRpnt, struct scsi_tape * STp, unsigned char *c } } - init_completion(&STp->wait); + /* If async IO, set last_SRpnt. This ptr tells write_behind_check + which IO is outstanding. It's nulled out when the IO completes. */ + if (!do_wait) + (STp->buffer)->last_SRpnt = SRpnt; + + waiting = &STp->wait; + init_completion(waiting); SRpnt->sr_use_sg = STp->buffer->do_dio || (bytes > (STp->buffer)->frp[0].length); if (SRpnt->sr_use_sg) { if (!STp->buffer->do_dio) @@ -438,17 +502,20 @@ st_do_scsi(struct scsi_request * SRpnt, struct scsi_tape * STp, unsigned char *c bp = (STp->buffer)->b_data; SRpnt->sr_data_direction = direction; SRpnt->sr_cmd_len = 0; - SRpnt->sr_request->waiting = &(STp->wait); + SRpnt->sr_request->waiting = waiting; SRpnt->sr_request->rq_status = RQ_SCSI_BUSY; SRpnt->sr_request->rq_disk = STp->disk; + SRpnt->sr_request->end_io = blk_end_sync_rq; STp->buffer->cmdstat.have_sense = 0; scsi_do_req(SRpnt, (void *) cmd, bp, bytes, st_sleep_done, timeout, retries); if (do_wait) { - wait_for_completion(SRpnt->sr_request->waiting); + wait_for_completion(waiting); SRpnt->sr_request->waiting = NULL; + if (SRpnt->sr_request->rq_status != RQ_SCSI_DONE) + SRpnt->sr_result |= (DRIVER_ERROR << 24); (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt); } return SRpnt; @@ -465,6 +532,7 @@ static int write_behind_check(struct scsi_tape * STp) struct st_buffer *STbuffer; struct st_partstat *STps; struct st_cmdstatus *cmdstatp; + struct scsi_request *SRpnt; STbuffer = STp->buffer; if (!STbuffer->writing) @@ -478,10 +546,14 @@ static int write_behind_check(struct scsi_tape * STp) ) /* end DEB */ wait_for_completion(&(STp->wait)); - (STp->buffer)->last_SRpnt->sr_request->waiting = NULL; + SRpnt = STbuffer->last_SRpnt; + STbuffer->last_SRpnt = NULL; + SRpnt->sr_request->waiting = NULL; + if (SRpnt->sr_request->rq_status != RQ_SCSI_DONE) + SRpnt->sr_result |= (DRIVER_ERROR << 24); - (STp->buffer)->syscall_result = st_chk_result(STp, (STp->buffer)->last_SRpnt); - scsi_release_request((STp->buffer)->last_SRpnt); + (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt); + scsi_release_request(SRpnt); STbuffer->buffer_bytes -= STbuffer->writing; STps = &(STp->ps[STp->partition]); @@ -1055,25 +1127,20 @@ static int st_open(struct inode *inode, struct file *filp) */ filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE); + if (!(STp = scsi_tape_get(dev))) + return -ENXIO; + write_lock(&st_dev_arr_lock); - if (dev >= st_dev_max || scsi_tapes == NULL || - ((STp = scsi_tapes[dev]) == NULL)) { - write_unlock(&st_dev_arr_lock); - return (-ENXIO); - } filp->private_data = STp; name = tape_name(STp); if (STp->in_use) { write_unlock(&st_dev_arr_lock); + scsi_tape_put(STp); DEB( printk(ST_DEB_MSG "%s: Device already in use.\n", name); ) return (-EBUSY); } - if(scsi_device_get(STp->device)) { - write_unlock(&st_dev_arr_lock); - return (-ENXIO); - } STp->in_use = 1; write_unlock(&st_dev_arr_lock); STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0; @@ -1118,7 +1185,7 @@ static int st_open(struct inode *inode, struct file *filp) err_out: normalize_buffer(STp->buffer); STp->in_use = 0; - scsi_device_put(STp->device); + scsi_tape_put(STp); return retval; } @@ -1250,7 +1317,7 @@ static int st_release(struct inode *inode, struct file *filp) write_lock(&st_dev_arr_lock); STp->in_use = 0; write_unlock(&st_dev_arr_lock); - scsi_device_put(STp->device); + scsi_tape_put(STp); return result; } @@ -3887,6 +3954,7 @@ static int st_probe(struct device *dev) goto out_put_disk; } memset(tpnt, 0, sizeof(struct scsi_tape)); + kref_init(&tpnt->kref); tpnt->disk = disk; sprintf(disk->disk_name, "st%d", i); disk->private_data = &tpnt->driver; @@ -3902,6 +3970,7 @@ static int st_probe(struct device *dev) tpnt->tape_type = MT_ISSCSI2; tpnt->buffer = buffer; + tpnt->buffer->last_SRpnt = NULL; tpnt->inited = 0; tpnt->dirty = 0; @@ -4076,15 +4145,10 @@ static int st_remove(struct device *dev) tpnt->modes[mode].cdevs[j] = NULL; } } - tpnt->device = NULL; - if (tpnt->buffer) { - tpnt->buffer->orig_frp_segs = 0; - normalize_buffer(tpnt->buffer); - kfree(tpnt->buffer); - } - put_disk(tpnt->disk); - kfree(tpnt); + down(&st_ref_sem); + kref_put(&tpnt->kref, scsi_tape_release); + up(&st_ref_sem); return 0; } } @@ -4093,6 +4157,34 @@ static int st_remove(struct device *dev) return 0; } +/** + * scsi_tape_release - Called to free the Scsi_Tape structure + * @kref: pointer to embedded kref + * + * st_ref_sem must be held entering this routine. Because it is + * called on last put, you should always use the scsi_tape_get() + * scsi_tape_put() helpers which manipulate the semaphore directly + * and never do a direct kref_put(). + **/ +static void scsi_tape_release(struct kref *kref) +{ + struct scsi_tape *tpnt = to_scsi_tape(kref); + struct gendisk *disk = tpnt->disk; + + tpnt->device = NULL; + + if (tpnt->buffer) { + tpnt->buffer->orig_frp_segs = 0; + normalize_buffer(tpnt->buffer); + kfree(tpnt->buffer); + } + + disk->private_data = NULL; + put_disk(disk); + kfree(tpnt); + return; +} + static void st_intr(struct scsi_cmnd *SCpnt) { scsi_io_completion(SCpnt, (SCpnt->result ? 0: SCpnt->bufflen), 1); diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h index 061da11..790acac 100644 --- a/drivers/scsi/st.h +++ b/drivers/scsi/st.h @@ -3,7 +3,7 @@ #define _ST_H #include <linux/completion.h> - +#include <linux/kref.h> /* Descriptor for analyzed sense data */ struct st_cmdstatus { @@ -156,6 +156,7 @@ struct scsi_tape { unsigned char last_sense[16]; #endif struct gendisk *disk; + struct kref kref; }; /* Bit masks for use_pf */ |
