Clear the error register only once before a sector read operation. Don't
clear it afterwards -- the caller needs it. Check the error register in
swim_read_sector() and return the appropriate error when necessary. Fully
validate the sector header. Don't terminate the search loop early just
because an erroneous sector header showed up.

Fixes: 8852ecd97488 ("m68k: mac - Add SWIM floppy support")
Signed-off-by: Finn Thain <fthain@linux-m68k.org>
---
 drivers/block/swim.c     | 13 +++++++------
 drivers/block/swim_asm.S |  8 --------
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/drivers/block/swim.c b/drivers/block/swim.c
index 9755b86d4dd4..e2a8c4ba4e39 100644
--- a/drivers/block/swim.c
+++ b/drivers/block/swim.c
@@ -483,20 +483,21 @@ static inline int swim_read_sector(struct floppy_state *fs,
 
 	local_irq_save(flags);
 	for (i = 0; i < 36; i++) {
-		ret = swim_read_sector_header(base, &header);
-		if (!ret && (header.sector == sector)) {
+		if (swim_read_sector_header(base, &header) ||
+		    swim_read(base, error) || header.track != track ||
+		    header.side != side || header.size != 2)
+			continue;
+		if (header.sector == sector) {
 			/* found */
 
 			ret = swim_read_sector_data(base, buffer);
+			if (swim_read(base, error))
+				ret = -EIO;
 			break;
 		}
 	}
 	local_irq_restore(flags);
 
-	if ((header.side != side)  || (header.track != track) ||
-	     (header.sector != sector))
-		return 0;
-
 	return ret;
 }
 
diff --git a/drivers/block/swim_asm.S b/drivers/block/swim_asm.S
index f40e19e48021..1d394ee930d6 100644
--- a/drivers/block/swim_asm.S
+++ b/drivers/block/swim_asm.S
@@ -67,7 +67,6 @@ mfm_read_addrmark:
 	movew	#seek_time, %d2
 
 wait_header_init:
-	tstb	%a3@(read_error - read_mark)
 	moveb	#0x18, %a3@(write_mode0 - read_mark)
 	moveb	#0x01, %a3@(write_mode1 - read_mark)
 	moveb	#0x01, %a3@(write_mode0 - read_mark)
@@ -139,8 +138,6 @@ crc1:	moveb	%a2@, %d5
 	andb	#.Lhr_crc_error, %d5
 	bne	signal_nonyb
 
-	tstb	%a3@(read_error - read_mark)
-
 	moveq	#0, %d0
 signal_nonyb:
 	moveb	#0x18, %a3@(write_mode0 - read_mark)
@@ -165,7 +162,6 @@ mfm_read_data:
 	movew	#seek_time, %d2
 
 wait_data_init:
-	tstb	%a3@(read_error - read_mark)
 	moveb	#0x18, %a3@(write_mode0 - read_mark)
 	moveb	#0x01, %a3@(write_mode1 - read_mark)
 	moveb	#0x01, %a3@(write_mode0 - read_mark)
@@ -190,8 +186,6 @@ wait_data_mark_byte:
 
 	/* read data */
 
-	tstb	%a3@(read_error - read_mark)
-
 	movel	#sector_size-1, %d4		/* sector size */
 read_new_data:
 	movew	#max_retry, %d2
@@ -232,8 +226,6 @@ data_crc1:
 	andb	#.Lhr_crc_error, %d5
 	bne	data_exit
 
-	tstb	%a3@(read_error - read_mark)
-
 	/* return number of bytes read */
 
 	movel	#sector_size, %d0
-- 
2.52.0