ncr5380: Change instance->host_lock to hostdata->lock
NCR5380.c presently uses the instance->host_lock spin lock. Convert this
to a new spin lock that protects the NCR5380_hostdata struct.
atari_NCR5380.c previously used local_irq_save/restore() rather than a
spin lock. Convert this to hostdata->lock in irq mode. For SMP platforms,
the interrupt handler now also acquires the spin lock.
This brings all locking in the two core drivers into agreement.
Adding this locking also means that a bunch of volatile qualifiers can be
removed from the members of the NCR5380_hostdata struct. This is done in
a subsequent patch.
Proper locking will allow the abort handler to locate a command being
aborted. This is presently impossible if the abort handler is invoked when
the command has been moved from a queue to a pointer on the stack. (If
eh_abort_handler can't determine whether a command has been completed
or is still being processed then it can't decide whether to return
success or failure.)
The hostdata spin lock is now held when calling NCR5380_select() and
NCR5380_information_transfer(). Where possible, the lock is dropped for
polling and PIO transfers.
Clean up the now-redundant SELECT_ENABLE_REG writes, that used to provide
limited mutual exclusion between information_transfer() and reselect().
Accessing hostdata->connected without data races means taking the lock;
cleanup these accesses.
The new spin lock falls away for m68k and other UP builds, so this should
have little impact there. In the SMP case the new lock should be
uncontested even when the SCSI bus is contested.
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/atari_NCR5380.c b/drivers/scsi/atari_NCR5380.c
index 08e8ace..2dd65cd 100644
--- a/drivers/scsi/atari_NCR5380.c
+++ b/drivers/scsi/atari_NCR5380.c
@@ -546,15 +546,13 @@
static void NCR5380_print(struct Scsi_Host *instance)
{
unsigned char status, data, basr, mr, icr, i;
- unsigned long flags;
- local_irq_save(flags);
data = NCR5380_read(CURRENT_SCSI_DATA_REG);
status = NCR5380_read(STATUS_REG);
mr = NCR5380_read(MODE_REG);
icr = NCR5380_read(INITIATOR_COMMAND_REG);
basr = NCR5380_read(BUS_AND_STATUS_REG);
- local_irq_restore(flags);
+
printk("STATUS_REG: %02x ", status);
for (i = 0; signals[i].mask; ++i)
if (status & signals[i].mask)
@@ -684,14 +682,12 @@
{
struct NCR5380_hostdata *hostdata;
struct scsi_cmnd *ptr;
- unsigned long flags;
NCR5380_dprint(NDEBUG_ANY, instance);
NCR5380_dprint_phase(NDEBUG_ANY, instance);
hostdata = (struct NCR5380_hostdata *)instance->hostdata;
- local_irq_save(flags);
if (!hostdata->connected)
printk("scsi%d: no currently connected command\n", HOSTNO);
else
@@ -704,8 +700,6 @@
for (ptr = (struct scsi_cmnd *) hostdata->disconnected_queue; ptr;
ptr = NEXT(ptr))
lprint_Scsi_Cmnd(ptr);
-
- local_irq_restore(flags);
printk("\n");
}
@@ -732,7 +726,7 @@
hostdata = (struct NCR5380_hostdata *)instance->hostdata;
- local_irq_save(flags);
+ spin_lock_irqsave(&hostdata->lock, flags);
if (!hostdata->connected)
seq_printf(m, "scsi%d: no currently connected command\n", HOSTNO);
else
@@ -746,7 +740,7 @@
ptr = NEXT(ptr))
show_Scsi_Cmnd(ptr, m);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
return 0;
}
@@ -784,6 +778,7 @@
#if defined (REAL_DMA)
hostdata->dma_len = 0;
#endif
+ spin_lock_init(&hostdata->lock);
hostdata->connected = NULL;
hostdata->issue_queue = NULL;
hostdata->disconnected_queue = NULL;
@@ -946,7 +941,7 @@
if (!NCR5380_acquire_dma_irq(instance))
return SCSI_MLQUEUE_HOST_BUSY;
- local_irq_save(flags);
+ spin_lock_irqsave(&hostdata->lock, flags);
/*
* Insert the cmd into the issue queue. Note that REQUEST SENSE
@@ -966,7 +961,7 @@
LIST(cmd, tmp);
SET_NEXT(tmp, cmd);
}
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
dprintk(NDEBUG_QUEUES, "scsi%d: command added to %s of queue\n", H_NO(cmd),
(cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");
@@ -1006,7 +1001,6 @@
struct Scsi_Host *instance = hostdata->host;
struct scsi_cmnd *tmp, *prev;
int done;
- unsigned long flags;
/*
* ++roman: Just disabling the NCR interrupt isn't sufficient here,
@@ -1014,9 +1008,8 @@
* alter queues and touch the Falcon lock.
*/
- local_save_flags(flags);
+ spin_lock_irq(&hostdata->lock);
do {
- local_irq_disable(); /* Freeze request queues */
done = 1;
if (!hostdata->connected) {
@@ -1043,7 +1036,6 @@
tmp, scmd_id(tmp), hostdata->busy[scmd_id(tmp)],
lun);
/* When we find one, remove it from the issue queue. */
- /* ++guenther: possible race with Falcon locking */
if (
#ifdef SUPPORT_TAGS
!is_lun_busy( tmp, tmp->cmnd[0] != REQUEST_SENSE)
@@ -1051,8 +1043,6 @@
!(hostdata->busy[tmp->device->id] & (1 << lun))
#endif
) {
- /* ++guenther: just to be sure, this must be atomic */
- local_irq_disable();
if (prev) {
REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));
SET_NEXT(prev, NEXT(tmp));
@@ -1063,9 +1053,6 @@
SET_NEXT(tmp, NULL);
hostdata->retain_dma_intr++;
- /* reenable interrupts after finding one */
- local_irq_restore(flags);
-
/*
* Attempt to establish an I_T_L nexus here.
* On success, instance->hostdata->connected is set.
@@ -1090,13 +1077,10 @@
#endif
if (!NCR5380_select(instance, tmp)) {
/* OK or bad target */
- local_irq_disable();
hostdata->retain_dma_intr--;
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
} else {
/* Need to retry */
- local_irq_disable();
LIST(tmp, hostdata->issue_queue);
SET_NEXT(tmp, hostdata->issue_queue);
hostdata->issue_queue = tmp;
@@ -1104,7 +1088,6 @@
cmd_free_tag(tmp);
#endif
hostdata->retain_dma_intr--;
- local_irq_restore(flags);
done = 0;
dprintk(NDEBUG_MAIN, "scsi%d: main(): select() failed, "
"returned to issue_queue\n", HOSTNO);
@@ -1120,7 +1103,6 @@
&& !hostdata->dma_len
#endif
) {
- local_irq_restore(flags);
dprintk(NDEBUG_MAIN, "scsi%d: main: performing information transfer\n",
HOSTNO);
NCR5380_information_transfer(instance);
@@ -1128,7 +1110,7 @@
done = 0;
}
} while (!done);
- local_irq_restore(flags);
+ spin_unlock_irq(&hostdata->lock);
}
@@ -1257,6 +1239,9 @@
struct NCR5380_hostdata *hostdata = shost_priv(instance);
int handled = 0;
unsigned char basr;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hostdata->lock, flags);
basr = NCR5380_read(BUS_AND_STATUS_REG);
if (basr & BASR_IRQ) {
@@ -1316,6 +1301,8 @@
#endif
}
+ spin_unlock_irqrestore(&hostdata->lock, flags);
+
return IRQ_RETVAL(handled);
}
@@ -1355,7 +1342,6 @@
unsigned char *data;
int len;
int err;
- unsigned long flags;
NCR5380_dprint(NDEBUG_ARBITRATION, instance);
dprintk(NDEBUG_ARBITRATION, "scsi%d: starting arbitration, id = %d\n", HOSTNO,
@@ -1366,11 +1352,6 @@
* data bus during SELECTION.
*/
- local_irq_save(flags);
- if (hostdata->connected) {
- local_irq_restore(flags);
- return -1;
- }
NCR5380_write(TARGET_COMMAND_REG, 0);
/*
@@ -1384,10 +1365,11 @@
* Bus Free Delay, arbitration will begin.
*/
- local_irq_restore(flags);
+ spin_unlock_irq(&hostdata->lock);
err = NCR5380_poll_politely2(instance, MODE_REG, MR_ARBITRATE, 0,
INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS,
ICR_ARBITRATION_PROGRESS, HZ);
+ spin_lock_irq(&hostdata->lock);
if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE)) {
/* Reselection interrupt */
return -1;
@@ -1398,6 +1380,7 @@
"select: arbitration timeout\n");
return -1;
}
+ spin_unlock_irq(&hostdata->lock);
/* The SCSI-2 arbitration delay is 2.4 us */
udelay(3);
@@ -1405,11 +1388,11 @@
/* Check for lost arbitration */
if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
(NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) ||
- (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
- hostdata->connected) {
+ (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST)) {
NCR5380_write(MODE_REG, MR_BASE);
dprintk(NDEBUG_ARBITRATION, "scsi%d: lost arbitration, deasserting MR_ARBITRATE\n",
HOSTNO);
+ spin_lock_irq(&hostdata->lock);
return -1;
}
@@ -1430,6 +1413,8 @@
else
udelay(2);
+ spin_lock_irq(&hostdata->lock);
+
/* NCR5380_reselect() clears MODE_REG after a reselection interrupt */
if (!(NCR5380_read(MODE_REG) & MR_ARBITRATE))
return -1;
@@ -1457,14 +1442,10 @@
* Reselect interrupts must be turned off prior to the dropping of BSY,
* otherwise we will trigger an interrupt.
*/
-
- if (hostdata->connected) {
- NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
- return -1;
- }
-
NCR5380_write(SELECT_ENABLE_REG, 0);
+ spin_unlock_irq(&hostdata->lock);
+
/*
* The initiator shall then wait at least two deskew delays and release
* the BSY signal.
@@ -1505,6 +1486,7 @@
msecs_to_jiffies(250));
if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
+ spin_lock_irq(&hostdata->lock);
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
NCR5380_reselect(instance);
if (!hostdata->connected)
@@ -1515,6 +1497,7 @@
}
if (err < 0) {
+ spin_lock_irq(&hostdata->lock);
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
cmd->result = DID_BAD_TARGET << 16;
#ifdef SUPPORT_TAGS
@@ -1554,6 +1537,7 @@
/* Wait for start of REQ/ACK handshake */
err = NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, HZ);
+ spin_lock_irq(&hostdata->lock);
if (err < 0) {
shost_printk(KERN_ERR, instance, "select: REQ timeout\n");
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
@@ -1583,6 +1567,7 @@
NCR5380_transfer_pio(instance, &phase, &len, &data);
dprintk(NDEBUG_SELECTION, "scsi%d: nexus established.\n", HOSTNO);
/* XXX need to handle errors here */
+
hostdata->connected = cmd;
#ifndef SUPPORT_TAGS
hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
@@ -1849,7 +1834,6 @@
SETUP_HOSTDATA(instance);
register int c = *count;
register unsigned char p = *phase;
- unsigned long flags;
#if defined(CONFIG_SUN3)
/* sanity check */
@@ -1865,7 +1849,6 @@
c, (p & SR_IO) ? "to" : "from", *data);
/* netbsd turns off ints here, why not be safe and do it too */
- local_irq_save(flags);
/* send start chain */
sun3scsi_dma_start(c, *data);
@@ -1885,8 +1868,6 @@
dregs->csr |= CSR_DMA_ENABLE;
#endif
- local_irq_restore(flags);
-
sun3_dma_active = 1;
#else /* !defined(CONFIG_SUN3) */
@@ -1913,11 +1894,9 @@
/* On the Medusa, it is a must to initialize the DMA before
* starting the NCR. This is also the cleaner way for the TT.
*/
- local_irq_save(flags);
hostdata->dma_len = (p & SR_IO) ?
NCR5380_dma_read_setup(instance, d, c) :
NCR5380_dma_write_setup(instance, d, c);
- local_irq_restore(flags);
}
if (p & SR_IO)
@@ -1931,11 +1910,9 @@
/* On the Falcon, the DMA setup must be done after the last */
/* NCR access, else the DMA setup gets trashed!
*/
- local_irq_save(flags);
hostdata->dma_len = (p & SR_IO) ?
NCR5380_dma_read_setup(instance, d, c) :
NCR5380_dma_write_setup(instance, d, c);
- local_irq_restore(flags);
}
#endif /* !defined(CONFIG_SUN3) */
@@ -1963,7 +1940,6 @@
static void NCR5380_information_transfer(struct Scsi_Host *instance)
{
SETUP_HOSTDATA(instance);
- unsigned long flags;
unsigned char msgout = NOP;
int sink = 0;
int len;
@@ -1972,13 +1948,13 @@
#endif
unsigned char *data;
unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
- struct scsi_cmnd *cmd = (struct scsi_cmnd *) hostdata->connected;
+ struct scsi_cmnd *cmd;
#ifdef SUN3_SCSI_VME
dregs->csr |= CSR_INTR;
#endif
- while (1) {
+ while ((cmd = hostdata->connected)) {
tmp = NCR5380_read(STATUS_REG);
/* We only have a valid SCSI phase when REQ is asserted */
if (tmp & SR_REQ) {
@@ -2112,9 +2088,13 @@
}
} else
#endif /* defined(REAL_DMA) */
+ {
+ spin_unlock_irq(&hostdata->lock);
NCR5380_transfer_pio(instance, &phase,
(int *)&cmd->SCp.this_residual,
(unsigned char **)&cmd->SCp.ptr);
+ spin_lock_irq(&hostdata->lock);
+ }
#if defined(CONFIG_SUN3) && defined(REAL_DMA)
/* if we had intended to dma that command clear it */
if (sun3_dma_setup_done == cmd)
@@ -2124,7 +2104,6 @@
case PHASE_MSGIN:
len = 1;
data = &tmp;
- NCR5380_write(SELECT_ENABLE_REG, 0); /* disable reselects */
NCR5380_transfer_pio(instance, &phase, &len, &data);
cmd->SCp.Message = tmp;
@@ -2136,7 +2115,6 @@
dprintk(NDEBUG_QUEUES, "scsi%d: command for target %d, lun %llu "
"completed\n", HOSTNO, cmd->device->id, cmd->device->lun);
- local_irq_save(flags);
hostdata->connected = NULL;
#ifdef SUPPORT_TAGS
cmd_free_tag(cmd);
@@ -2152,8 +2130,6 @@
#else
hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
#endif
- /* Enable reselect interrupts */
- NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
/*
* I'm not sure what the correct thing to do here is :
@@ -2211,13 +2187,10 @@
* disconnected queue.
*/
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
return;
case MESSAGE_REJECT:
/* Accept message by clearing ACK */
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
- /* Enable reselect interrupts */
- NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
switch (hostdata->last_message) {
case HEAD_OF_QUEUE_TAG:
case ORDERED_QUEUE_TAG:
@@ -2241,12 +2214,10 @@
case DISCONNECT:
/* Accept message by clearing ACK */
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
- local_irq_save(flags);
LIST(cmd,hostdata->disconnected_queue);
SET_NEXT(cmd, hostdata->disconnected_queue);
hostdata->connected = NULL;
hostdata->disconnected_queue = cmd;
- local_irq_restore(flags);
dprintk(NDEBUG_QUEUES, "scsi%d: command for target %d lun %llu was "
"moved from connected to the "
"disconnected_queue\n", HOSTNO,
@@ -2277,8 +2248,6 @@
case RESTORE_POINTERS:
/* Accept message by clearing ACK */
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
- /* Enable reselect interrupts */
- NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
break;
case EXTENDED_MESSAGE:
/*
@@ -2297,6 +2266,8 @@
/* Accept first byte by clearing ACK */
NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
+ spin_unlock_irq(&hostdata->lock);
+
dprintk(NDEBUG_EXTENDED, "scsi%d: receiving extended message\n", HOSTNO);
len = 2;
@@ -2335,6 +2306,11 @@
HOSTNO, extended_msg[2], extended_msg[1]);
tmp = 0;
}
+
+ spin_lock_irq(&hostdata->lock);
+ if (!hostdata->connected)
+ return;
+
/* Fall through to reject message */
/*
@@ -2367,7 +2343,6 @@
hostdata->last_message = msgout;
NCR5380_transfer_pio(instance, &phase, &len, &data);
if (msgout == ABORT) {
- local_irq_save(flags);
#ifdef SUPPORT_TAGS
cmd_free_tag(cmd);
#else
@@ -2376,7 +2351,6 @@
hostdata->connected = NULL;
cmd->result = DID_ERROR << 16;
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
cmd->scsi_done(cmd);
NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
return;
@@ -2404,9 +2378,11 @@
NCR5380_dprint(NDEBUG_ANY, instance);
} /* switch(phase) */
} else {
+ spin_unlock_irq(&hostdata->lock);
NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, HZ);
+ spin_lock_irq(&hostdata->lock);
}
- } /* while (1) */
+ }
}
/*
@@ -2639,9 +2615,9 @@
scmd_printk(KERN_NOTICE, cmd, "aborting command\n");
- NCR5380_print_status(instance);
+ spin_lock_irqsave(&hostdata->lock, flags);
- local_irq_save(flags);
+ NCR5380_print_status(instance);
dprintk(NDEBUG_ABORT, "scsi%d: abort called basr 0x%02x, sr 0x%02x\n", HOSTNO,
NCR5380_read(BUS_AND_STATUS_REG),
@@ -2683,11 +2659,11 @@
hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
#endif
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
cmd->scsi_done(cmd);
return SUCCESS;
} else {
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
printk("scsi%d: abort of connected command failed!\n", HOSTNO);
return FAILED;
}
@@ -2707,7 +2683,7 @@
SET_NEXT(tmp, NULL);
tmp->result = DID_ABORT << 16;
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
dprintk(NDEBUG_ABORT, "scsi%d: abort removed command from issue queue.\n",
HOSTNO);
/* Tagged queuing note: no tag to free here, hasn't been assigned
@@ -2729,7 +2705,7 @@
*/
if (hostdata->connected) {
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
dprintk(NDEBUG_ABORT, "scsi%d: abort failed, command connected.\n", HOSTNO);
return FAILED;
}
@@ -2762,17 +2738,16 @@
for (tmp = (struct scsi_cmnd *) hostdata->disconnected_queue; tmp;
tmp = NEXT(tmp)) {
if (cmd == tmp) {
- local_irq_restore(flags);
dprintk(NDEBUG_ABORT, "scsi%d: aborting disconnected command.\n", HOSTNO);
- if (NCR5380_select(instance, cmd))
+ if (NCR5380_select(instance, cmd)) {
+ spin_unlock_irq(&hostdata->lock);
return FAILED;
-
+ }
dprintk(NDEBUG_ABORT, "scsi%d: nexus reestablished.\n", HOSTNO);
do_abort(instance);
- local_irq_save(flags);
for (prev = (struct scsi_cmnd **)&(hostdata->disconnected_queue),
tmp = (struct scsi_cmnd *)hostdata->disconnected_queue;
tmp; prev = NEXTADDR(tmp), tmp = NEXT(tmp)) {
@@ -2791,7 +2766,7 @@
hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
#endif
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
tmp->scsi_done(tmp);
return SUCCESS;
}
@@ -2804,7 +2779,7 @@
* released after the abort, in case it is kept due to some bug.
*/
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
/*
* Case 5 : If we reached this point, the command was not found in any of
@@ -2836,7 +2811,7 @@
int i;
unsigned long flags;
- local_irq_save(flags);
+ spin_lock_irqsave(&hostdata->lock, flags);
#if (NDEBUG & NDEBUG_ANY)
scmd_printk(KERN_INFO, cmd, "performing bus reset\n");
@@ -2876,7 +2851,7 @@
#endif
maybe_release_dma_irq(instance);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&hostdata->lock, flags);
return SUCCESS;
}