[PATCH 4/4] cdrom: revert commit 22a9189 (cdrom: use kmalloced buffers instead of buffers on stack)

FUJITA Tomonori
2008-05-20T04:58:34Z

The commit 22a9189fd073db3d03a4cf8b8c098aa207602de1 (cdrom: use
kmalloced buffers instead of buffers on stack) is introduced to use
kmalloced buffers for packet commands to avoid stack corruption on non
coherent platforms.

SCSI cdrom uses blk_rq_map_kern (the commit
68154e90c9d1492d570671ae181d9a8f8530da55) post 2.6.25. So sr_packet
uses allocated pages when necessary. IDE cdrom has a mechnism to
handle alignment and padding. So we don't need this extra complexitiy
in cdrom.c.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
---
drivers/cdrom/cdrom.c | 274 +++++++++++++++++--------------------------------
1 files changed, 93 insertions(+), 181 deletions(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 69f26eb..a5da356 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -461,37 +461,27 @@ int cdrom_get_media_event(struct cdrom_device_info *cdi,
struct media_event_desc *med)
{
struct packet_command cgc;
- unsigned char *buffer;
- struct event_header *eh;
- int ret = 1;
-
- buffer = kmalloc(8, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
+ unsigned char buffer[8];
+ struct event_header *eh = (struct event_header *) buffer;

- eh = (struct event_header *)buffer;
-
- init_cdrom_command(&cgc, buffer, 8, CGC_DATA_READ);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);
cgc.cmd[0] = GPCMD_GET_EVENT_STATUS_NOTIFICATION;
cgc.cmd[1] = 1; /* IMMED */
cgc.cmd[4] = 1 << 4; /* media event */
- cgc.cmd[8] = 8;
+ cgc.cmd[8] = sizeof(buffer);
cgc.quiet = 1;

if (cdi->ops->generic_packet(cdi, &cgc))
- goto err;
+ return 1;

if (be16_to_cpu(eh->data_len) < sizeof(*med))
- goto err;
+ return 1;

if (eh->nea || eh->notification_class != 0x4)
- goto err;
+ return 1;

- memcpy(med, buffer + sizeof(*eh), sizeof(*med));
- ret = 0;
-err:
- kfree(buffer);
- return ret;
+ memcpy(med, &buffer[sizeof(*eh)], sizeof(*med));
+ return 0;
}

/*
@@ -501,82 +491,68 @@ err:
static int cdrom_mrw_probe_pc(struct cdrom_device_info *cdi)
{
struct packet_command cgc;
- char *buffer;
- int ret = 1;
-
- buffer = kmalloc(16, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
+ char buffer[16];

- init_cdrom_command(&cgc, buffer, 16, CGC_DATA_READ);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);

cgc.timeout = HZ;
cgc.quiet = 1;

if (!cdrom_mode_sense(cdi, &cgc, MRW_MODE_PC, 0)) {
cdi->mrw_mode_page = MRW_MODE_PC;
- ret = 0;
+ return 0;
} else if (!cdrom_mode_sense(cdi, &cgc, MRW_MODE_PC_PRE1, 0)) {
cdi->mrw_mode_page = MRW_MODE_PC_PRE1;
- ret = 0;
+ return 0;
}
- kfree(buffer);
- return ret;
+
+ return 1;
}

static int cdrom_is_mrw(struct cdrom_device_info *cdi, int *write)
{
struct packet_command cgc;
struct mrw_feature_desc *mfd;
- unsigned char *buffer;
+ unsigned char buffer[16];
int ret;

*write = 0;
- buffer = kmalloc(16, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;

- init_cdrom_command(&cgc, buffer, 16, CGC_DATA_READ);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);

cgc.cmd[0] = GPCMD_GET_CONFIGURATION;
cgc.cmd[3] = CDF_MRW;
- cgc.cmd[8] = 16;
+ cgc.cmd[8] = sizeof(buffer);
cgc.quiet = 1;

if ((ret = cdi->ops->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

mfd = (struct mrw_feature_desc *)&buffer[sizeof(struct feature_header)];
- if (be16_to_cpu(mfd->feature_code) != CDF_MRW) {
- ret = 1;
- goto err;
- }
+ if (be16_to_cpu(mfd->feature_code) != CDF_MRW)
+ return 1;
*write = mfd->write;

if ((ret = cdrom_mrw_probe_pc(cdi))) {
*write = 0;
+ return ret;
}
-err:
- kfree(buffer);
- return ret;
+
+ return 0;
}

static int cdrom_mrw_bgformat(struct cdrom_device_info *cdi, int cont)
{
struct packet_command cgc;
- unsigned char *buffer;
+ unsigned char buffer[12];
int ret;

printk(KERN_INFO "cdrom: %sstarting format\n", cont ? "Re" : "");

- buffer = kmalloc(12, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
/*
* FmtData bit set (bit 4), format type is 1
*/
- init_cdrom_command(&cgc, buffer, 12, CGC_DATA_WRITE);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_WRITE);
cgc.cmd[0] = GPCMD_FORMAT_UNIT;
cgc.cmd[1] = (1 << 4) | 1;

@@ -603,7 +579,6 @@ static int cdrom_mrw_bgformat(struct cdrom_device_info *cdi, int cont)
if (ret)
printk(KERN_INFO "cdrom: bgformat failed\n");

- kfree(buffer);
return ret;
}

@@ -663,17 +638,16 @@ static int cdrom_mrw_set_lba_space(struct cdrom_device_info *cdi, int space)
{
struct packet_command cgc;
struct mode_page_header *mph;
- char *buffer;
+ char buffer[16];
int ret, offset, size;

- buffer = kmalloc(16, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);

- init_cdrom_command(&cgc, buffer, 16, CGC_DATA_READ);
+ cgc.buffer = buffer;
+ cgc.buflen = sizeof(buffer);

if ((ret = cdrom_mode_sense(cdi, &cgc, cdi->mrw_mode_page, 0)))
- goto err;
+ return ret;

mph = (struct mode_page_header *) buffer;
offset = be16_to_cpu(mph->desc_length);
@@ -683,70 +657,55 @@ static int cdrom_mrw_set_lba_space(struct cdrom_device_info *cdi, int space)
cgc.buflen = size;

if ((ret = cdrom_mode_select(cdi, &cgc)))
- goto err;
+ return ret;

printk(KERN_INFO "cdrom: %s: mrw address space %s selected\n", cdi->name, mrw_address_space[space]);
- ret = 0;
-err:
- kfree(buffer);
- return ret;
+ return 0;
}

static int cdrom_get_random_writable(struct cdrom_device_info *cdi,
struct rwrt_feature_desc *rfd)
{
struct packet_command cgc;
- char *buffer;
+ char buffer[24];
int ret;

- buffer = kmalloc(24, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
- init_cdrom_command(&cgc, buffer, 24, CGC_DATA_READ);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);

cgc.cmd[0] = GPCMD_GET_CONFIGURATION; /* often 0x46 */
cgc.cmd[3] = CDF_RWRT; /* often 0x0020 */
- cgc.cmd[8] = 24; /* often 0x18 */
+ cgc.cmd[8] = sizeof(buffer); /* often 0x18 */
cgc.quiet = 1;

if ((ret = cdi->ops->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

memcpy(rfd, &buffer[sizeof(struct feature_header)], sizeof (*rfd));
- ret = 0;
-err:
- kfree(buffer);
- return ret;
+ return 0;
}

static int cdrom_has_defect_mgt(struct cdrom_device_info *cdi)
{
struct packet_command cgc;
- char *buffer;
+ char buffer[16];
__be16 *feature_code;
int ret;

- buffer = kmalloc(16, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
- init_cdrom_command(&cgc, buffer, 16, CGC_DATA_READ);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);

cgc.cmd[0] = GPCMD_GET_CONFIGURATION;
cgc.cmd[3] = CDF_HWDM;
- cgc.cmd[8] = 16;
+ cgc.cmd[8] = sizeof(buffer);
cgc.quiet = 1;

if ((ret = cdi->ops->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

feature_code = (__be16 *) &buffer[sizeof(struct feature_header)];
if (be16_to_cpu(*feature_code) == CDF_HWDM)
- ret = 0;
-err:
- kfree(buffer);
- return ret;
+ return 0;
+
+ return 1;
}

@@ -837,14 +796,10 @@ static int cdrom_mrw_open_write(struct cdrom_device_info *cdi)
static int mo_open_write(struct cdrom_device_info *cdi)
{
struct packet_command cgc;
- char *buffer;
+ char buffer[255];
int ret;

- buffer = kmalloc(255, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
- init_cdrom_command(&cgc, buffer, 4, CGC_DATA_READ);
+ init_cdrom_command(&cgc, &buffer, 4, CGC_DATA_READ);
cgc.quiet = 1;

/*
@@ -861,15 +816,10 @@ static int mo_open_write(struct cdrom_device_info *cdi)
}

/* drive gave us no info, let the user go ahead */
- if (ret) {
- ret = 0;
- goto err;
- }
+ if (ret)
+ return 0;

- ret = buffer[3] & 0x80;
-err:
- kfree(buffer);
- return ret;
+ return buffer[3] & 0x80;
}

static int cdrom_ram_open_write(struct cdrom_device_info *cdi)
@@ -892,19 +842,15 @@ static int cdrom_ram_open_write(struct cdrom_device_info *cdi)
static void cdrom_mmc3_profile(struct cdrom_device_info *cdi)
{
struct packet_command cgc;
- char *buffer;
+ char buffer[32];
int ret, mmc3_profile;

- buffer = kmalloc(32, GFP_KERNEL);
- if (!buffer)
- return;
-
- init_cdrom_command(&cgc, buffer, 32, CGC_DATA_READ);
+ init_cdrom_command(&cgc, buffer, sizeof(buffer), CGC_DATA_READ);

cgc.cmd[0] = GPCMD_GET_CONFIGURATION;
cgc.cmd[1] = 0;
cgc.cmd[2] = cgc.cmd[3] = 0; /* Starting Feature Number */
- cgc.cmd[8] = 32; /* Allocation Length */
+ cgc.cmd[8] = sizeof(buffer); /* Allocation Length */
cgc.quiet = 1;

if ((ret = cdi->ops->generic_packet(cdi, &cgc)))
@@ -913,7 +859,6 @@ static void cdrom_mmc3_profile(struct cdrom_device_info *cdi)
mmc3_profile = (buffer[6] << 8) | buffer[7];

cdi->mmc3_profile = mmc3_profile;
- kfree(buffer);
}

static int cdrom_is_dvd_rw(struct cdrom_device_info *cdi)
@@ -1628,15 +1573,12 @@ static void setup_send_key(struct packet_command *cgc, unsigned agid, unsigned t
static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
{
int ret;
- u_char *buf;
+ u_char buf[20];
struct packet_command cgc;
struct cdrom_device_ops *cdo = cdi->ops;
- rpc_state_t *rpc_state;
-
- buf = kzalloc(20, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
+ rpc_state_t rpc_state;

+ memset(buf, 0, sizeof(buf));
init_cdrom_command(&cgc, buf, 0, CGC_DATA_READ);

switch (ai->type) {
@@ -1647,7 +1589,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
setup_report_key(&cgc, ai->lsa.agid, 0);

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

ai->lsa.agid = buf[7] >> 6;
/* Returning data, let host change state */
@@ -1658,7 +1600,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
setup_report_key(&cgc, ai->lsk.agid, 2);

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

copy_key(ai->lsk.key, &buf[4]);
/* Returning data, let host change state */
@@ -1669,7 +1611,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
setup_report_key(&cgc, ai->lsc.agid, 1);

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

copy_chal(ai->lsc.chal, &buf[4]);
/* Returning data, let host change state */
@@ -1686,7 +1628,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
cgc.cmd[2] = ai->lstk.lba >> 24;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

ai->lstk.cpm = (buf[4] >> 7) & 1;
ai->lstk.cp_sec = (buf[4] >> 6) & 1;
@@ -1700,7 +1642,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
setup_report_key(&cgc, ai->lsasf.agid, 5);

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

ai->lsasf.asf = buf[7] & 1;
break;
@@ -1713,7 +1655,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
copy_chal(&buf[4], ai->hsc.chal);

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

ai->type = DVD_LU_SEND_KEY1;
break;
@@ -1726,7 +1668,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)

if ((ret = cdo->generic_packet(cdi, &cgc))) {
ai->type = DVD_AUTH_FAILURE;
- goto err;
+ return ret;
}
ai->type = DVD_AUTH_ESTABLISHED;
break;
@@ -1737,23 +1679,24 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
cdinfo(CD_DVD, "entering DVD_INVALIDATE_AGID\n");
setup_report_key(&cgc, ai->lsa.agid, 0x3f);
if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;
break;

/* Get region settings */
case DVD_LU_SEND_RPC_STATE:
cdinfo(CD_DVD, "entering DVD_LU_SEND_RPC_STATE\n");
setup_report_key(&cgc, 0, 8);
+ memset(&rpc_state, 0, sizeof(rpc_state_t));
+ cgc.buffer = (char *) &rpc_state;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

- rpc_state = (rpc_state_t *)buf;
- ai->lrpcs.type = rpc_state->type_code;
- ai->lrpcs.vra = rpc_state->vra;
- ai->lrpcs.ucca = rpc_state->ucca;
- ai->lrpcs.region_mask = rpc_state->region_mask;
- ai->lrpcs.rpc_scheme = rpc_state->rpc_scheme;
+ ai->lrpcs.type = rpc_state.type_code;
+ ai->lrpcs.vra = rpc_state.vra;
+ ai->lrpcs.ucca = rpc_state.ucca;
+ ai->lrpcs.region_mask = rpc_state.region_mask;
+ ai->lrpcs.rpc_scheme = rpc_state.rpc_scheme;
break;

/* Set region settings */
@@ -1764,23 +1707,20 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
buf[4] = ai->hrpcs.pdrc;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;
break;

default:
cdinfo(CD_WARNING, "Invalid DVD key ioctl (%d)\n", ai->type);
- ret = -ENOTTY;
- goto err;
+ return -ENOTTY;
}
- ret = 0;
-err:
- kfree(buf);
- return ret;
+
+ return 0;
}

static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s)
{
- unsigned char *buf, *base;
+ unsigned char buf[21], *base;
struct dvd_layer *layer;
struct packet_command cgc;
struct cdrom_device_ops *cdo = cdi->ops;
@@ -1789,11 +1729,7 @@ static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s)
if (layer_num >= DVD_LAYERS)
return -EINVAL;

- buf = kmalloc(21, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- init_cdrom_command(&cgc, buf, 21, CGC_DATA_READ);
+ 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;
@@ -1805,7 +1741,7 @@ static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s)
cgc.quiet = 1;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

base = &buf[4];
layer = &s->physical.layer[layer_num];
@@ -1829,24 +1765,17 @@ static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s)
layer->end_sector_l0 = base[13] << 16 | base[14] << 8 | base[15];
layer->bca = base[16] >> 7;

- ret = 0;
-err:
- kfree(buf);
- return ret;
+ return 0;
}

static int dvd_read_copyright(struct cdrom_device_info *cdi, dvd_struct *s)
{
int ret;
- u_char *buf;
+ u_char buf[8];
struct packet_command cgc;
struct cdrom_device_ops *cdo = cdi->ops;

- buf = kmalloc(8, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- init_cdrom_command(&cgc, buf, 8, CGC_DATA_READ);
+ 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;
@@ -1854,15 +1783,12 @@ static int dvd_read_copyright(struct cdrom_device_info *cdi, dvd_struct *s)
cgc.cmd[9] = cgc.buflen & 0xff;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

s->copyright.cpst = buf[4];
s->copyright.rmi = buf[5];

- ret = 0;
-err:
- kfree(buf);
- return ret;
+ return 0;
}

static int dvd_read_disckey(struct cdrom_device_info *cdi, dvd_struct *s)
@@ -1894,33 +1820,26 @@ static int dvd_read_disckey(struct cdrom_device_info *cdi, dvd_struct *s)
static int dvd_read_bca(struct cdrom_device_info *cdi, dvd_struct *s)
{
int ret;
- u_char *buf;
+ u_char buf[4 + 188];
struct packet_command cgc;
struct cdrom_device_ops *cdo = cdi->ops;

- buf = kmalloc(4 + 188, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- init_cdrom_command(&cgc, buf, 4 + 188, CGC_DATA_READ);
+ 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;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

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);
- ret = -EIO;
- goto err;
+ return -EIO;
}
memcpy(s->bca.value, &buf[4], s->bca.len);
- ret = 0;
-err:
- kfree(buf);
- return ret;
+
+ return 0;
}

static int dvd_read_manufact(struct cdrom_device_info *cdi, dvd_struct *s)
@@ -2020,13 +1939,9 @@ static int cdrom_read_subchannel(struct cdrom_device_info *cdi,
{
struct cdrom_device_ops *cdo = cdi->ops;
struct packet_command cgc;
- char *buffer;
+ char buffer[32];
int ret;

- buffer = kmalloc(32, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
init_cdrom_command(&cgc, buffer, 16, CGC_DATA_READ);
cgc.cmd[0] = GPCMD_READ_SUBCHANNEL;
cgc.cmd[1] = 2; /* MSF addressing */
@@ -2035,7 +1950,7 @@ static int cdrom_read_subchannel(struct cdrom_device_info *cdi,
cgc.cmd[8] = 16;

if ((ret = cdo->generic_packet(cdi, &cgc)))
- goto err;
+ return ret;

subchnl->cdsc_audiostatus = cgc.buffer[1];
subchnl->cdsc_format = CDROM_MSF;
@@ -2050,10 +1965,7 @@ static int cdrom_read_subchannel(struct cdrom_device_info *cdi,
subchnl->cdsc_absaddr.msf.second = cgc.buffer[10];
subchnl->cdsc_absaddr.msf.frame = cgc.buffer[11];

- ret = 0;
-err:
- kfree(buffer);
- return ret;
+ return 0;
}

/*
--
1.5.4.2