Avoid using a too big bounce buffer by splitting up large reads. Allows

for booting using large (64k) blocksize filesystems. ok tedu@

2 files changed, 36 insertions, 8 deletions

diff --git a/sys/arch/amd64/stand/libsa/biosdev.c b/sys/arch/amd64/stand/libsa/biosdev.c
index 4ca8436f32c..fdd1c90170a 100644
--- a/sys/arch/amd64/stand/libsa/biosdev.c
+++ b/sys/arch/amd64/stand/libsa/biosdev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: biosdev.c,v 1.32 2018/08/10 16:41:35 jsing Exp $	*/
+/*	$OpenBSD: biosdev.c,v 1.33 2018/12/16 08:33:16 otto Exp $	*/
 
 /*
  * Copyright (c) 1996 Michael Shalayeff
@@ -340,11 +340,26 @@ biosd_io(int rw, bios_diskinfo_t *bd, u_int off, int nsect, void *buf)
 	return error;
 }
 
+#define MAXSECTS 32
+
 int
 biosd_diskio(int rw, struct diskinfo *dip, u_int off, int nsect, void *buf)
 {
-	return biosd_io(rw, &dip->bios_info, off, nsect, buf);
+	char *dest = buf;
+	int n, ret;
+
+	/*
+	 * Avoid doing too large reads, the bounce buffer used by biosd_io()
+	 * might run us out-of-mem.
+	 */
+	for (ret = 0; ret == 0 && nsect > 0;
+	    off += MAXSECTS, dest += MAXSECTS * DEV_BSIZE, nsect -= MAXSECTS) {
+		n = nsect >= MAXSECTS ? MAXSECTS : nsect;
+		ret = biosd_io(rw, &dip->bios_info, off, n, dest);
+	}
+	return ret;
 }
+
 /*
  * Try to read the bsd label on the given BIOS device.
  */
@@ -715,7 +730,6 @@ biosstrategy(void *devdata, int rw, daddr32_t blk, size_t size, void *buf,
     size_t *rsize)
 {
 	struct diskinfo *dip = (struct diskinfo *)devdata;
-	bios_diskinfo_t *bd = &dip->bios_info;
 	u_int8_t error = 0;
 	size_t nsect;
 
@@ -732,7 +746,7 @@ biosstrategy(void *devdata, int rw, daddr32_t blk, size_t size, void *buf,
 	if (blk < 0)
 		error = EINVAL;
 	else
-		error = biosd_io(rw, bd, blk, nsect, buf);
+		error = biosd_diskio(rw, dip, blk, nsect, buf);
 
 #ifdef BIOS_DEBUG
 	if (debug) {
diff --git a/sys/arch/i386/stand/libsa/biosdev.c b/sys/arch/i386/stand/libsa/biosdev.c
index 7baddd2f145..394fc6b061d 100644
--- a/sys/arch/i386/stand/libsa/biosdev.c
+++ b/sys/arch/i386/stand/libsa/biosdev.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: biosdev.c,v 1.98 2018/09/06 11:50:54 jsg Exp $	*/
+/*	$OpenBSD: biosdev.c,v 1.99 2018/12/16 08:33:16 otto Exp $	*/
 
 /*
  * Copyright (c) 1996 Michael Shalayeff
@@ -341,11 +341,26 @@ biosd_io(int rw, bios_diskinfo_t *bd, u_int off, int nsect, void *buf)
 	return error;
 }
 
+#define MAXSECTS 32
+
 int
 biosd_diskio(int rw, struct diskinfo *dip, u_int off, int nsect, void *buf)
 {
-	return biosd_io(rw, &dip->bios_info, off, nsect, buf);
+	char *dest = buf;
+	int n, ret;
+
+	/*
+	 * Avoid doing too large reads, the bounce buffer used by biosd_io()
+	 * might run us out-of-mem.
+	 */
+	for (ret = 0; ret == 0 && nsect > 0;
+	    off += MAXSECTS, dest += MAXSECTS * DEV_BSIZE, nsect -= MAXSECTS) {
+		n = nsect >= MAXSECTS ? MAXSECTS : nsect;
+		ret = biosd_io(rw, &dip->bios_info, off, n, dest);
+	}
+	return ret;
 }
+
 /*
  * Try to read the bsd label on the given BIOS device.
  */
@@ -716,7 +731,6 @@ biosstrategy(void *devdata, int rw, daddr32_t blk, size_t size, void *buf,
     size_t *rsize)
 {
 	struct diskinfo *dip = (struct diskinfo *)devdata;
-	bios_diskinfo_t *bd = &dip->bios_info;
 	u_int8_t error = 0;
 	size_t nsect;
 
@@ -733,7 +747,7 @@ biosstrategy(void *devdata, int rw, daddr32_t blk, size_t size, void *buf,
 	if (blk < 0)
 		error = EINVAL;
 	else
-		error = biosd_io(rw, bd, blk, nsect, buf);
+		error = biosd_diskio(rw, dip, blk, nsect, buf);
 
 #ifdef BIOS_DEBUG
 	if (debug) {