scsi: NCR5380: Remove context check

NCR5380_poll_politely2() uses in_interrupt() and irqs_disabled() to check
if it is safe to sleep.

Such usage in drivers is phased out and Linus clearly requested that code
which changes behaviour depending on context should either be separated, or
the context be explicitly conveyed in an argument passed by the caller.

Below is a context analysis of NCR5380_poll_politely2() uppermost callers:

- NCR5380_maybe_reset_bus(), task, invoked during device probe.
-> NCR5380_poll_politely()
-> do_abort()

- NCR5380_select(), task, but can only sleep in the "release, then
re-acquire" regions of the spinlock held by its caller.
Sleeping invocations (lock released):
-> NCR5380_poll_politely2()

Atomic invocations (lock acquired):
-> NCR5380_reselect()
-> NCR5380_poll_politely()
-> do_abort()
-> NCR5380_transfer_pio()

- NCR5380_intr(), interrupt handler
-> NCR5380_dma_complete()
-> NCR5380_transfer_pio()
-> NCR5380_poll_politely()
-> NCR5380_reselect() (see above)

- NCR5380_information_transfer(), task, but can only sleep in the
"release, then re-acquire" regions of the caller-held spinlock.
Sleeping invocations (lock released):
- NCR5380_transfer_pio() -> NCR5380_poll_politely()
- NCR5380_poll_politely()

Atomic invocations (lock acquired):
- NCR5380_transfer_dma()
-> NCR5380_dma_recv_setup()
=> generic_NCR5380_precv() -> NCR5380_poll_politely()
=> macscsi_pread() -> NCR5380_poll_politely()

-> NCR5380_dma_send_setup()
=> generic_NCR5380_psend -> NCR5380_poll_politely2()
=> macscsi_pwrite() -> NCR5380_poll_politely()

-> NCR5380_poll_politely2()
-> NCR5380_dma_complete()
-> NCR5380_transfer_pio()
-> NCR5380_poll_politely()
- NCR5380_transfer_pio() -> NCR5380_poll_politely

- NCR5380_reselect(), atomic, always called with hostdata spinlock
held.

Since NCR5380_poll_politely2() already takes a "wait" argument in jiffies,
use it to determine if the function can sleep. Modify atomic callers, which
passed an unused wait value in terms of HZ, to pass zero.

Link: https://lore.kernel.org/r/[e-mail]
Cc: Michael Schmitz <[e-mail]>
Cc: <[e-mail]>
Suggested-by: Finn Thain <[e-mail]>
Co-developed-by: Sebastian Andrzej Siewior <[e-mail]>
Acked-by: Finn Thain <[e-mail]>
Signed-off-by: Ahmed S. Darwish <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/NCR5380.c

···
 static unsigned int disconnect_mask = ~0;
 module_param(disconnect_mask, int, 0444);
 
-static int do_abort(struct Scsi_Host *);
+static int do_abort(struct Scsi_Host *, unsigned int);
 static void do_reset(struct Scsi_Host *);
 static void bus_reset_cleanup(struct Scsi_Host *);
 
···
  * @reg2: Second 5380 register to poll
  * @bit2: Second bitmask to check
  * @val2: Second expected value
- * @wait: Time-out in jiffies
+ * @wait: Time-out in jiffies, 0 if sleeping is not allowed
  *
  * Polls the chip in a reasonably efficient manner waiting for an
  * event to occur. After a short quick poll we begin to yield the CPU
···
 		cpu_relax();
 	} while (n--);
 
-	if (irqs_disabled() || in_interrupt())
+	if (!wait)
 		return -ETIMEDOUT;
 
 	/* Repeatedly sleep for 1 ms until deadline */
···
 			break;
 		case 2:
 			shost_printk(KERN_ERR, instance, "bus busy, attempting abort\n");
-			do_abort(instance);
+			do_abort(instance, 1);
 			break;
 		case 4:
 			shost_printk(KERN_ERR, instance, "bus busy, attempting reset\n");
···
 			if (toPIO > 0) {
 				dsprintk(NDEBUG_DMA, instance,
 				         "Doing %d byte PIO to 0x%p\n", cnt, *data);
-				NCR5380_transfer_pio(instance, &p, &cnt, data);
+				NCR5380_transfer_pio(instance, &p, &cnt, data, 0);
 				*count -= toPIO - cnt;
 			}
 		}
···
 		goto out;
 	}
 	if (!hostdata->selecting) {
-		do_abort(instance);
+		do_abort(instance, 0);
 		return false;
 	}
 
···
 	len = 1;
 	data = tmp;
 	phase = PHASE_MSGOUT;
-	NCR5380_transfer_pio(instance, &phase, &len, &data);
+	NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 	if (len) {
 		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 		cmd->result = DID_ERROR << 16;
···
  *
  * Inputs : instance - instance of driver, *phase - pointer to
  * what phase is expected, *count - pointer to number of
- * bytes to transfer, **data - pointer to data pointer.
+ * bytes to transfer, **data - pointer to data pointer,
+ * can_sleep - 1 or 0 when sleeping is permitted or not, respectively.
  *
  * Returns : -1 when different phase is entered without transferring
  * maximum number of bytes, 0 if all bytes are transferred or exit
···
 
 static int NCR5380_transfer_pio(struct Scsi_Host *instance,
 				unsigned char *phase, int *count,
-				unsigned char **data)
+				unsigned char **data, unsigned int can_sleep)
 {
 	struct NCR5380_hostdata *hostdata = shost_priv(instance);
 	unsigned char p = *phase, tmp;
···
 		 * valid
 		 */
 
-		if (NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ, HZ) < 0)
+		if (NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ,
+					  HZ * can_sleep) < 0)
 			break;
 
 		dsprintk(NDEBUG_HANDSHAKE, instance, "REQ asserted\n");
···
 		}
 
 		if (NCR5380_poll_politely(hostdata,
-		                          STATUS_REG, SR_REQ, 0, 5 * HZ) < 0)
+		                          STATUS_REG, SR_REQ, 0, 5 * HZ * can_sleep) < 0)
 			break;
 
 		dsprintk(NDEBUG_HANDSHAKE, instance, "REQ negated, handshake complete\n");
···
  * do_abort - abort the currently established nexus by going to
  * MESSAGE OUT phase and sending an ABORT message.
  * @instance: relevant scsi host instance
+ * @can_sleep: 1 or 0 when sleeping is permitted or not, respectively
  *
  * Returns 0 on success, negative error code on failure.
  */
 
-static int do_abort(struct Scsi_Host *instance)
+static int do_abort(struct Scsi_Host *instance, unsigned int can_sleep)
 {
 	struct NCR5380_hostdata *hostdata = shost_priv(instance);
 	unsigned char *msgptr, phase, tmp;
···
 	 * the target sees, so we just handshake.
 	 */
 
-	rc = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ, 10 * HZ);
+	rc = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, SR_REQ,
+				   10 * HZ * can_sleep);
 	if (rc < 0)
 		goto out;
 
···
 	if (tmp != PHASE_MSGOUT) {
 		NCR5380_write(INITIATOR_COMMAND_REG,
 		              ICR_BASE | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
-		rc = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, 0, 3 * HZ);
+		rc = NCR5380_poll_politely(hostdata, STATUS_REG, SR_REQ, 0,
+					   3 * HZ * can_sleep);
 		if (rc < 0)
 			goto out;
 		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
···
 	msgptr = &tmp;
 	len = 1;
 	phase = PHASE_MSGOUT;
-	NCR5380_transfer_pio(instance, &phase, &len, &msgptr);
+	NCR5380_transfer_pio(instance, &phase, &len, &msgptr, can_sleep);
 	if (len)
 		rc = -ENXIO;
 
···
 			 */
 
 			if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
-			                          BASR_DRQ, BASR_DRQ, HZ) < 0) {
+			                          BASR_DRQ, BASR_DRQ, 0) < 0) {
 				result = -1;
 				shost_printk(KERN_ERR, instance, "PDMA read: DRQ timeout\n");
 			}
 			if (NCR5380_poll_politely(hostdata, STATUS_REG,
-			                          SR_REQ, 0, HZ) < 0) {
+			                          SR_REQ, 0, 0) < 0) {
 				result = -1;
 				shost_printk(KERN_ERR, instance, "PDMA read: !REQ timeout\n");
 			}
···
 			 */
 			if (NCR5380_poll_politely2(hostdata,
 			     BUS_AND_STATUS_REG, BASR_DRQ, BASR_DRQ,
-			     BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, HZ) < 0) {
+			     BUS_AND_STATUS_REG, BASR_PHASE_MATCH, 0, 0) < 0) {
 				result = -1;
 				shost_printk(KERN_ERR, instance, "PDMA write: DRQ and phase timeout\n");
 			}
···
 #if (NDEBUG & NDEBUG_NO_DATAOUT)
 				shost_printk(KERN_DEBUG, instance, "NDEBUG_NO_DATAOUT set, attempted DATAOUT aborted\n");
 				sink = 1;
-				do_abort(instance);
+				do_abort(instance, 0);
 				cmd->result = DID_ERROR << 16;
 				complete_cmd(instance, cmd);
 				hostdata->connected = NULL;
···
 							   NCR5380_PIO_CHUNK_SIZE);
 					len = transfersize;
 					NCR5380_transfer_pio(instance, &phase, &len,
-					                     (unsigned char **)&cmd->SCp.ptr);
+					                     (unsigned char **)&cmd->SCp.ptr,
+							     0);
 					cmd->SCp.this_residual -= transfersize - len;
 				}
 #ifdef CONFIG_SUN3
···
 			case PHASE_MSGIN:
 				len = 1;
 				data = &tmp;
-				NCR5380_transfer_pio(instance, &phase, &len, &data);
+				NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 				cmd->SCp.Message = tmp;
 
 				switch (tmp) {
···
 					len = 2;
 					data = extended_msg + 1;
 					phase = PHASE_MSGIN;
-					NCR5380_transfer_pio(instance, &phase, &len, &data);
+					NCR5380_transfer_pio(instance, &phase, &len, &data, 1);
 					dsprintk(NDEBUG_EXTENDED, instance, "length %d, code 0x%02x\n",
 					         (int)extended_msg[1],
 					         (int)extended_msg[2]);
···
 						data = extended_msg + 3;
 						phase = PHASE_MSGIN;
 
-						NCR5380_transfer_pio(instance, &phase, &len, &data);
+						NCR5380_transfer_pio(instance, &phase, &len, &data, 1);
 						dsprintk(NDEBUG_EXTENDED, instance, "message received, residual %d\n",
 						         len);
 
···
 				len = 1;
 				data = &msgout;
 				hostdata->last_message = msgout;
-				NCR5380_transfer_pio(instance, &phase, &len, &data);
+				NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 				if (msgout == ABORT) {
 					hostdata->connected = NULL;
 					hostdata->busy[scmd_id(cmd)] &= ~(1 << cmd->device->lun);
···
 				 * PSEUDO-DMA architecture we should probably
 				 * use the dma transfer function.
 				 */
-				NCR5380_transfer_pio(instance, &phase, &len, &data);
+				NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 				break;
 			case PHASE_STATIN:
 				len = 1;
 				data = &tmp;
-				NCR5380_transfer_pio(instance, &phase, &len, &data);
+				NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 				cmd->SCp.Status = tmp;
 				break;
 			default:
···
 
 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_BSY);
 	if (NCR5380_poll_politely(hostdata,
-	                          STATUS_REG, SR_SEL, 0, 2 * HZ) < 0) {
+	                          STATUS_REG, SR_SEL, 0, 0) < 0) {
 		shost_printk(KERN_ERR, instance, "reselect: !SEL timeout\n");
 		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 		return;
···
 	 */
 
 	if (NCR5380_poll_politely(hostdata,
-	                          STATUS_REG, SR_REQ, SR_REQ, 2 * HZ) < 0) {
+	                          STATUS_REG, SR_REQ, SR_REQ, 0) < 0) {
 		if ((NCR5380_read(STATUS_REG) & (SR_BSY | SR_SEL)) == 0)
 			/* BUS FREE phase */
 			return;
 		shost_printk(KERN_ERR, instance, "reselect: REQ timeout\n");
-		do_abort(instance);
+		do_abort(instance, 0);
 		return;
 	}
 
···
 		unsigned char *data = msg;
 		unsigned char phase = PHASE_MSGIN;
 
-		NCR5380_transfer_pio(instance, &phase, &len, &data);
+		NCR5380_transfer_pio(instance, &phase, &len, &data, 0);
 
 		if (len) {
-			do_abort(instance);
+			do_abort(instance, 0);
 			return;
 		}
 	}
···
 		shost_printk(KERN_ERR, instance, "expecting IDENTIFY message, got ");
 		spi_print_msg(msg);
 		printk("\n");
-		do_abort(instance);
+		do_abort(instance, 0);
 		return;
 	}
 	lun = msg[0] & 0x07;
···
 		 * Since we have an established nexus that we can't do anything
 		 * with, we must abort it.
 		 */
-		if (do_abort(instance) == 0)
+		if (do_abort(instance, 0) == 0)
 			hostdata->busy[target] &= ~(1 << lun);
 		return;
 	}
···
 		dsprintk(NDEBUG_ABORT, instance, "abort: cmd %p is connected\n", cmd);
 		hostdata->connected = NULL;
 		hostdata->dma_len = 0;
-		if (do_abort(instance) < 0) {
+		if (do_abort(instance, 0) < 0) {
 			set_host_byte(cmd, DID_ERROR);
 			complete_cmd(instance, cmd);
 			result = FAILED;

drivers/scsi/NCR5380.h

···
 static void NCR5380_reselect(struct Scsi_Host *instance);
 static bool NCR5380_select(struct Scsi_Host *, struct scsi_cmnd *);
 static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
-static int NCR5380_transfer_pio(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data);
+static int NCR5380_transfer_pio(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data,
+				unsigned int can_sleep);
 static int NCR5380_poll_politely2(struct NCR5380_hostdata *,
                                   unsigned int, u8, u8,
                                   unsigned int, u8, u8, unsigned long);

drivers/scsi/g_NCR5380.c

···
 		if (start == len - 128) {
 			/* Ignore End of DMA interrupt for the final buffer */
 			if (NCR5380_poll_politely(hostdata, hostdata->c400_ctl_status,
-			                          CSR_HOST_BUF_NOT_RDY, 0, HZ / 64) < 0)
+			                          CSR_HOST_BUF_NOT_RDY, 0, 0) < 0)
 				break;
 		} else {
 			if (NCR5380_poll_politely2(hostdata, hostdata->c400_ctl_status,
 			                           CSR_HOST_BUF_NOT_RDY, 0,
 			                           hostdata->c400_ctl_status,
 			                           CSR_GATED_53C80_IRQ,
-			                           CSR_GATED_53C80_IRQ, HZ / 64) < 0 ||
+			                           CSR_GATED_53C80_IRQ, 0) < 0 ||
 			    NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY)
 				break;
 		}
···
 	if (residual == 0 && NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
 	                                           BASR_END_DMA_TRANSFER,
 	                                           BASR_END_DMA_TRANSFER,
-	                                           HZ / 64) < 0)
+						   0) < 0)
 		scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout\n",
 		            __func__);
 
···
 		                           CSR_HOST_BUF_NOT_RDY, 0,
 		                           hostdata->c400_ctl_status,
 		                           CSR_GATED_53C80_IRQ,
-		                           CSR_GATED_53C80_IRQ, HZ / 64) < 0 ||
+		                           CSR_GATED_53C80_IRQ, 0) < 0 ||
 		    NCR5380_read(hostdata->c400_ctl_status) & CSR_HOST_BUF_NOT_RDY) {
 			/* Both 128 B buffers are in use */
 			if (start >= 128)
···
 	if (residual == 0) {
 		if (NCR5380_poll_politely(hostdata, TARGET_COMMAND_REG,
 		                          TCR_LAST_BYTE_SENT, TCR_LAST_BYTE_SENT,
-		                          HZ / 64) < 0)
+					  0) < 0)
 			scmd_printk(KERN_ERR, hostdata->connected,
 			            "%s: Last Byte Sent timeout\n", __func__);
 
 		if (NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
 		                          BASR_END_DMA_TRANSFER, BASR_END_DMA_TRANSFER,
-		                          HZ / 64) < 0)
+					  0) < 0)
 			scmd_printk(KERN_ERR, hostdata->connected, "%s: End of DMA timeout\n",
 			            __func__);
 	}

drivers/scsi/mac_scsi.c

···
 
 	while (!NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
 	                              BASR_DRQ | BASR_PHASE_MATCH,
-	                              BASR_DRQ | BASR_PHASE_MATCH, HZ / 64)) {
+	                              BASR_DRQ | BASR_PHASE_MATCH, 0)) {
 		int bytes;
 
 		if (macintosh_config->ident == MAC_MODEL_IIFX)
···
 
 		if (NCR5380_poll_politely2(hostdata, STATUS_REG, SR_REQ, SR_REQ,
 		                           BUS_AND_STATUS_REG, BASR_ACK,
-		                           BASR_ACK, HZ / 64) < 0)
+		                           BASR_ACK, 0) < 0)
 			scmd_printk(KERN_DEBUG, hostdata->connected,
 			            "%s: !REQ and !ACK\n", __func__);
 		if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))
···
 
 	while (!NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG,
 	                              BASR_DRQ | BASR_PHASE_MATCH,
-	                              BASR_DRQ | BASR_PHASE_MATCH, HZ / 64)) {
+	                              BASR_DRQ | BASR_PHASE_MATCH, 0)) {
 		int bytes;
 
 		if (macintosh_config->ident == MAC_MODEL_IIFX)
···
 			if (NCR5380_poll_politely(hostdata, TARGET_COMMAND_REG,
 			                          TCR_LAST_BYTE_SENT,
 			                          TCR_LAST_BYTE_SENT,
-			                          HZ / 64) < 0) {
+			                          0) < 0) {
 				scmd_printk(KERN_ERR, hostdata->connected,
 				            "%s: Last Byte Sent timeout\n", __func__);
 				result = -1;
···
 
 		if (NCR5380_poll_politely2(hostdata, STATUS_REG, SR_REQ, SR_REQ,
 		                           BUS_AND_STATUS_REG, BASR_ACK,
-		                           BASR_ACK, HZ / 64) < 0)
+		                           BASR_ACK, 0) < 0)
 			scmd_printk(KERN_DEBUG, hostdata->connected,
 			            "%s: !REQ and !ACK\n", __func__);
 		if (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH))