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path: root/drivers/scsi/st.c
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Diffstat (limited to 'drivers/scsi/st.c')
-rw-r--r--drivers/scsi/st.c150
1 files changed, 121 insertions, 29 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 0a7839db5752..9aadf2fcad6a 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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-14 00:38:46 +0000