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Date:      Fri, 16 Dec 2016 19:09:57 +0000 (UTC)
From:      Oleksandr Tymoshenko <gonzo@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r310170 - head/sys/dev/spibus
Message-ID:  <201612161909.uBGJ9vro043276@repo.freebsd.org>
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Author: gonzo
Date: Fri Dec 16 19:09:57 2016
New Revision: 310170
URL: https://svnweb.freebsd.org/changeset/base/310170

Log:
  [spigen] Make "data" part of spigen_transfer optional
  
  Make st_data part of spigen_transfer optional by letting pass zero length
  and NULL pointer. SPI controller drivers handle this case fine.
  
  MFC after:	1 week

Modified:
  head/sys/dev/spibus/spigen.c

Modified: head/sys/dev/spibus/spigen.c
==============================================================================
--- head/sys/dev/spibus/spigen.c	Fri Dec 16 18:38:31 2016	(r310169)
+++ head/sys/dev/spibus/spigen.c	Fri Dec 16 19:09:57 2016	(r310170)
@@ -204,7 +204,7 @@ spigen_transfer(struct cdev *cdev, struc
 	int error = 0;
 
 	mtx_lock(&sc->sc_mtx);
-	if (st->st_command.iov_len == 0 || st->st_data.iov_len == 0)
+	if (st->st_command.iov_len == 0)
 		error = EINVAL;
 	else if (st->st_command.iov_len > sc->sc_command_length_max ||
 	    st->st_data.iov_len > sc->sc_data_length_max)
@@ -221,16 +221,20 @@ spigen_transfer(struct cdev *cdev, struc
 	    M_DEVBUF, M_WAITOK);
 	if (transfer.tx_cmd == NULL)
 		return (ENOMEM);
-	transfer.tx_data = transfer.rx_data = malloc(st->st_data.iov_len,
-	    M_DEVBUF, M_WAITOK);
-	if (transfer.tx_data == NULL) {
-		free(transfer.tx_cmd, M_DEVBUF);
-		return (ENOMEM);
+	if (st->st_data.iov_len > 0) {
+		transfer.tx_data = transfer.rx_data = malloc(st->st_data.iov_len,
+		    M_DEVBUF, M_WAITOK);
+		if (transfer.tx_data == NULL) {
+			free(transfer.tx_cmd, M_DEVBUF);
+			return (ENOMEM);
+		}
 	}
+	else
+		transfer.tx_data = transfer.rx_data = NULL;
 
 	error = copyin(st->st_command.iov_base, transfer.tx_cmd,
 	    transfer.tx_cmd_sz = transfer.rx_cmd_sz = st->st_command.iov_len);	
-	if (error == 0)
+	if ((error == 0) && (st->st_data.iov_len > 0))
 		error = copyin(st->st_data.iov_base, transfer.tx_data,
 		    transfer.tx_data_sz = transfer.rx_data_sz =
 		                          st->st_data.iov_len);	
@@ -239,7 +243,7 @@ spigen_transfer(struct cdev *cdev, struc
 	if (error == 0) {
 		error = copyout(transfer.rx_cmd, st->st_command.iov_base,
 		    transfer.rx_cmd_sz);
-		if (error == 0)
+		if ((error == 0) && (st->st_data.iov_len > 0))
 			error = copyout(transfer.rx_data, st->st_data.iov_base,
 			    transfer.rx_data_sz);
 	}

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