Commit d194139c authored by Marcin Slusarz's avatar Marcin Slusarz Committed by Jens Axboe
Browse files

cdrom: reduce stack usage of mmc_ioctl_dvd_read_struct 



1. kmalloc 192 bytes in dvd_read_bca (which is inlined into dvd_read_struct)
2. Pass struct packet_command to all dvd_read_* functions.

Checkstack output:
Before: mmc_ioctl_dvd_read_struct:         280
After:  mmc_ioctl_dvd_read_struct:         56

Signed-off-by: default avatarMarcin Slusarz <marcin.slusarz@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 3147c531

drivers/cdrom/cdrom.c

+77 −62
Original line number Diff line number Diff line
@@ -1712,29 +1712,30 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai) 
	return 0;

}



static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s)

static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s,

				struct packet_command *cgc)

{

	unsigned char buf[21], *base;

	struct dvd_layer *layer;

	struct packet_command cgc;

	struct cdrom_device_ops *cdo = cdi->ops;

	int ret, layer_num = s->physical.layer_num;



	if (layer_num >= DVD_LAYERS)

		return -EINVAL;



	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);

	cgc.cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc.cmd[6] = layer_num;

	cgc.cmd[7] = s->type;

	cgc.cmd[9] = cgc.buflen & 0xff;

	init_cdrom_command(cgc, buf, sizeof(buf), CGC_DATA_READ);

	cgc->cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc->cmd[6] = layer_num;

	cgc->cmd[7] = s->type;

	cgc->cmd[9] = cgc->buflen & 0xff;



	/*

	 * refrain from reporting errors on non-existing layers (mainly)

	 */

	cgc.quiet = 1;

	cgc->quiet = 1;



	if ((ret = cdo->generic_packet(cdi, &cgc)))

	ret = cdo->generic_packet(cdi, cgc);

	if (ret)

		return ret;



	base = &buf[4];
@@ -1762,21 +1763,22 @@ static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s) 
	return 0;

}



static int dvd_read_copyright(struct cdrom_device_info *cdi, dvd_struct *s)

static int dvd_read_copyright(struct cdrom_device_info *cdi, dvd_struct *s,

				struct packet_command *cgc)

{

	int ret;

	u_char buf[8];

	struct packet_command cgc;

	struct cdrom_device_ops *cdo = cdi->ops;



	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);

	cgc.cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc.cmd[6] = s->copyright.layer_num;

	cgc.cmd[7] = s->type;

	cgc.cmd[8] = cgc.buflen >> 8;

	cgc.cmd[9] = cgc.buflen & 0xff;

	init_cdrom_command(cgc, buf, sizeof(buf), CGC_DATA_READ);

	cgc->cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc->cmd[6] = s->copyright.layer_num;

	cgc->cmd[7] = s->type;

	cgc->cmd[8] = cgc->buflen >> 8;

	cgc->cmd[9] = cgc->buflen & 0xff;



	if ((ret = cdo->generic_packet(cdi, &cgc)))

	ret = cdo->generic_packet(cdi, cgc);

	if (ret)

		return ret;



	s->copyright.cpst = buf[4];
@@ -1785,79 +1787,89 @@ static int dvd_read_copyright(struct cdrom_device_info *cdi, dvd_struct *s) 
	return 0;

}



static int dvd_read_disckey(struct cdrom_device_info *cdi, dvd_struct *s)

static int dvd_read_disckey(struct cdrom_device_info *cdi, dvd_struct *s,

				struct packet_command *cgc)

{

	int ret, size;

	u_char *buf;

	struct packet_command cgc;

	struct cdrom_device_ops *cdo = cdi->ops;



	size = sizeof(s->disckey.value) + 4;



	if ((buf = kmalloc(size, GFP_KERNEL)) == NULL)

	buf = kmalloc(size, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	init_cdrom_command(&cgc, buf, size, CGC_DATA_READ);

	cgc.cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc.cmd[7] = s->type;

	cgc.cmd[8] = size >> 8;

	cgc.cmd[9] = size & 0xff;

	cgc.cmd[10] = s->disckey.agid << 6;

	init_cdrom_command(cgc, buf, size, CGC_DATA_READ);

	cgc->cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc->cmd[7] = s->type;

	cgc->cmd[8] = size >> 8;

	cgc->cmd[9] = size & 0xff;

	cgc->cmd[10] = s->disckey.agid << 6;



	if (!(ret = cdo->generic_packet(cdi, &cgc)))

	ret = cdo->generic_packet(cdi, cgc);

	if (!ret)

		memcpy(s->disckey.value, &buf[4], sizeof(s->disckey.value));



	kfree(buf);

	return ret;

}



static int dvd_read_bca(struct cdrom_device_info *cdi, dvd_struct *s)

static int dvd_read_bca(struct cdrom_device_info *cdi, dvd_struct *s,

			struct packet_command *cgc)

{

	int ret;

	u_char buf[4 + 188];

	struct packet_command cgc;

	int ret, size = 4 + 188;

	u_char *buf;

	struct cdrom_device_ops *cdo = cdi->ops;



	init_cdrom_command(&cgc, buf, sizeof(buf), CGC_DATA_READ);

	cgc.cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc.cmd[7] = s->type;

	cgc.cmd[9] = cgc.buflen & 0xff;

	buf = kmalloc(size, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	if ((ret = cdo->generic_packet(cdi, &cgc)))

		return ret;

	init_cdrom_command(cgc, buf, size, CGC_DATA_READ);

	cgc->cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc->cmd[7] = s->type;

	cgc->cmd[9] = cgc->buflen & 0xff;



	ret = cdo->generic_packet(cdi, cgc);

	if (ret)

		goto out;



	s->bca.len = buf[0] << 8 | buf[1];

	if (s->bca.len < 12 || s->bca.len > 188) {

		cdinfo(CD_WARNING, "Received invalid BCA length (%d)\n", s->bca.len);

		return -EIO;

		ret = -EIO;

		goto out;

	}

	memcpy(s->bca.value, &buf[4], s->bca.len);



	return 0;

	ret = 0;

out:

	kfree(buf);

	return ret;

}



static int dvd_read_manufact(struct cdrom_device_info *cdi, dvd_struct *s)

static int dvd_read_manufact(struct cdrom_device_info *cdi, dvd_struct *s,

				struct packet_command *cgc)

{

	int ret = 0, size;

	u_char *buf;

	struct packet_command cgc;

	struct cdrom_device_ops *cdo = cdi->ops;



	size = sizeof(s->manufact.value) + 4;



	if ((buf = kmalloc(size, GFP_KERNEL)) == NULL)

	buf = kmalloc(size, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	init_cdrom_command(&cgc, buf, size, CGC_DATA_READ);

	cgc.cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc.cmd[7] = s->type;

	cgc.cmd[8] = size >> 8;

	cgc.cmd[9] = size & 0xff;

	init_cdrom_command(cgc, buf, size, CGC_DATA_READ);

	cgc->cmd[0] = GPCMD_READ_DVD_STRUCTURE;

	cgc->cmd[7] = s->type;

	cgc->cmd[8] = size >> 8;

	cgc->cmd[9] = size & 0xff;



	if ((ret = cdo->generic_packet(cdi, &cgc))) {

		kfree(buf);

		return ret;

	}

	ret = cdo->generic_packet(cdi, cgc);

	if (ret)

		goto out;



	s->manufact.len = buf[0] << 8 | buf[1];

	if (s->manufact.len < 0 || s->manufact.len > 2048) {
@@ -1868,27 +1880,29 @@ static int dvd_read_manufact(struct cdrom_device_info *cdi, dvd_struct *s) 
		memcpy(s->manufact.value, &buf[4], s->manufact.len);

	}



out:

	kfree(buf);

	return ret;

}



static int dvd_read_struct(struct cdrom_device_info *cdi, dvd_struct *s)

static int dvd_read_struct(struct cdrom_device_info *cdi, dvd_struct *s,

				struct packet_command *cgc)

{

	switch (s->type) {

	case DVD_STRUCT_PHYSICAL:

		return dvd_read_physical(cdi, s);

		return dvd_read_physical(cdi, s, cgc);



	case DVD_STRUCT_COPYRIGHT:

		return dvd_read_copyright(cdi, s);

		return dvd_read_copyright(cdi, s, cgc);



	case DVD_STRUCT_DISCKEY:

		return dvd_read_disckey(cdi, s);

		return dvd_read_disckey(cdi, s, cgc);



	case DVD_STRUCT_BCA:

		return dvd_read_bca(cdi, s);

		return dvd_read_bca(cdi, s, cgc);



	case DVD_STRUCT_MANUFACT:

		return dvd_read_manufact(cdi, s);

		return dvd_read_manufact(cdi, s, cgc);

		

	default:

		cdinfo(CD_WARNING, ": Invalid DVD structure read requested (%d)\n",
@@ -3027,7 +3041,8 @@ static noinline int mmc_ioctl_cdrom_pause_resume(struct cdrom_device_info *cdi, 
}



static noinline int mmc_ioctl_dvd_read_struct(struct cdrom_device_info *cdi,

						void __user *arg)

						void __user *arg,

						struct packet_command *cgc)

{

	int ret;

	dvd_struct *s;
@@ -3046,7 +3061,7 @@ static noinline int mmc_ioctl_dvd_read_struct(struct cdrom_device_info *cdi, 
		return -EFAULT;

	}



	ret = dvd_read_struct(cdi, s);

	ret = dvd_read_struct(cdi, s, cgc);

	if (ret)

		goto out;
@@ -3132,7 +3147,7 @@ static int mmc_ioctl(struct cdrom_device_info *cdi, unsigned int cmd, 
	case CDROMRESUME:

		return mmc_ioctl_cdrom_pause_resume(cdi, &cgc, cmd);

	case DVD_READ_STRUCT:

		return mmc_ioctl_dvd_read_struct(cdi, userptr);

		return mmc_ioctl_dvd_read_struct(cdi, userptr, &cgc);

	case DVD_AUTH:

		return mmc_ioctl_dvd_auth(cdi, userptr);

	case CDROM_NEXT_WRITABLE:

CRA Git | Maintained and supported by SUSTech CRA and CCSE