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block: move cmdfilter from gendisk to request_queue
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cmd_filter works only for the block layer SG_IO with SCSI block
devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI
character devices (such as st). We hit a kernel crash with them.

The problem is that cmd_filter code accesses to gendisk (having struct
blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only
SCSI block device files. With character device files, inode->i_bdev
leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter
isn't safe.

SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be
independent on any protocols. We shouldn't change ULDs to expose their
gendisk.

This patch moves struct blk_scsi_cmd_filter from gendisk to
request_queue, a common object, which eveyone can access to.

The user interface doesn't change; users can change the filters via
/sys/block/. gendisk has a pointer to request_queue so the cmd_filter
code accesses to struct blk_scsi_cmd_filter.

Signed-off-by: FUJITA Tomonori <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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@fujita
fujita authored and Jens Axboe committed Aug 27, 2008
1 parent 1941246 commit abf5439
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Showing 7 changed files with 132 additions and 163 deletions.
2 changes: 2 additions & 0 deletions block/blk-core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -582,6 +582,8 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)

q->sg_reserved_size = INT_MAX;

blk_set_cmd_filter_defaults(&q->cmd_filter);

/*
* all done
*/
Expand Down
44 changes: 11 additions & 33 deletions block/bsg.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,8 +45,6 @@ struct bsg_device {
char name[BUS_ID_SIZE];
int max_queue;
unsigned long flags;
struct blk_scsi_cmd_filter *cmd_filter;
mode_t *f_mode;
};

enum {
Expand Down Expand Up @@ -174,7 +172,8 @@ static int bsg_io_schedule(struct bsg_device *bd)
}

static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
struct sg_io_v4 *hdr, struct bsg_device *bd)
struct sg_io_v4 *hdr, struct bsg_device *bd,
int has_write_perm)
{
if (hdr->request_len > BLK_MAX_CDB) {
rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL);
Expand All @@ -187,8 +186,7 @@ static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq,
return -EFAULT;

if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) {
if (blk_cmd_filter_verify_command(bd->cmd_filter, rq->cmd,
bd->f_mode))
if (blk_verify_command(&q->cmd_filter, rq->cmd, has_write_perm))
return -EPERM;
} else if (!capable(CAP_SYS_RAWIO))
return -EPERM;
Expand Down Expand Up @@ -244,7 +242,7 @@ bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw)
* map sg_io_v4 to a request.
*/
static struct request *
bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, int has_write_perm)
{
struct request_queue *q = bd->queue;
struct request *rq, *next_rq = NULL;
Expand All @@ -266,7 +264,7 @@ bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr)
rq = blk_get_request(q, rw, GFP_KERNEL);
if (!rq)
return ERR_PTR(-ENOMEM);
ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd);
ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm);
if (ret)
goto out;

Expand Down Expand Up @@ -568,25 +566,6 @@ static inline void bsg_set_block(struct bsg_device *bd, struct file *file)
set_bit(BSG_F_BLOCK, &bd->flags);
}

static void bsg_set_cmd_filter(struct bsg_device *bd,
struct file *file)
{
struct inode *inode;
struct gendisk *disk;

if (!file)
return;

inode = file->f_dentry->d_inode;
if (!inode)
return;

disk = inode->i_bdev->bd_disk;

bd->cmd_filter = &disk->cmd_filter;
bd->f_mode = &file->f_mode;
}

/*
* Check if the error is a "real" error that we should return.
*/
Expand All @@ -608,7 +587,6 @@ bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
dprintk("%s: read %Zd bytes\n", bd->name, count);

bsg_set_block(bd, file);
bsg_set_cmd_filter(bd, file);

bytes_read = 0;
ret = __bsg_read(buf, count, bd, NULL, &bytes_read);
Expand All @@ -621,7 +599,7 @@ bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
}

static int __bsg_write(struct bsg_device *bd, const char __user *buf,
size_t count, ssize_t *bytes_written)
size_t count, ssize_t *bytes_written, int has_write_perm)
{
struct bsg_command *bc;
struct request *rq;
Expand Down Expand Up @@ -652,7 +630,7 @@ static int __bsg_write(struct bsg_device *bd, const char __user *buf,
/*
* get a request, fill in the blanks, and add to request queue
*/
rq = bsg_map_hdr(bd, &bc->hdr);
rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm);
if (IS_ERR(rq)) {
ret = PTR_ERR(rq);
rq = NULL;
Expand Down Expand Up @@ -683,10 +661,11 @@ bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
dprintk("%s: write %Zd bytes\n", bd->name, count);

bsg_set_block(bd, file);
bsg_set_cmd_filter(bd, file);

bytes_written = 0;
ret = __bsg_write(bd, buf, count, &bytes_written);
ret = __bsg_write(bd, buf, count, &bytes_written,
file->f_mode & FMODE_WRITE);

*ppos = bytes_written;

/*
Expand Down Expand Up @@ -792,7 +771,6 @@ static struct bsg_device *bsg_add_device(struct inode *inode,
bd->queue = rq;

bsg_set_block(bd, file);
bsg_set_cmd_filter(bd, file);

atomic_set(&bd->ref_count, 1);
mutex_lock(&bsg_mutex);
Expand Down Expand Up @@ -943,7 +921,7 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (copy_from_user(&hdr, uarg, sizeof(hdr)))
return -EFAULT;

rq = bsg_map_hdr(bd, &hdr);
rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE);
if (IS_ERR(rq))
return PTR_ERR(rq);

Expand Down
118 changes: 6 additions & 112 deletions block/cmd-filter.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,8 @@
#include <scsi/scsi.h>
#include <linux/cdrom.h>

int blk_cmd_filter_verify_command(struct blk_scsi_cmd_filter *filter,
unsigned char *cmd, mode_t *f_mode)
int blk_verify_command(struct blk_scsi_cmd_filter *filter,
unsigned char *cmd, int has_write_perm)
{
/* root can do any command. */
if (capable(CAP_SYS_RAWIO))
Expand All @@ -43,30 +43,11 @@ int blk_cmd_filter_verify_command(struct blk_scsi_cmd_filter *filter,
return 0;

/* Write-safe commands require a writable open */
if (test_bit(cmd[0], filter->write_ok) && (*f_mode & FMODE_WRITE))
if (test_bit(cmd[0], filter->write_ok) && has_write_perm)
return 0;

return -EPERM;
}
EXPORT_SYMBOL(blk_cmd_filter_verify_command);

int blk_verify_command(struct file *file, unsigned char *cmd)
{
struct gendisk *disk;
struct inode *inode;

if (!file)
return -EINVAL;

inode = file->f_dentry->d_inode;
if (!inode)
return -EINVAL;

disk = inode->i_bdev->bd_disk;

return blk_cmd_filter_verify_command(&disk->cmd_filter,
cmd, &file->f_mode);
}
EXPORT_SYMBOL(blk_verify_command);

/* and now, the sysfs stuff */
Expand Down Expand Up @@ -219,114 +200,27 @@ static struct kobj_type rcf_ktype = {
.default_attrs = default_attrs,
};

#ifndef MAINTENANCE_IN_CMD
#define MAINTENANCE_IN_CMD 0xa3
#endif

static void rcf_set_defaults(struct blk_scsi_cmd_filter *filter)
{
/* Basic read-only commands */
__set_bit(TEST_UNIT_READY, filter->read_ok);
__set_bit(REQUEST_SENSE, filter->read_ok);
__set_bit(READ_6, filter->read_ok);
__set_bit(READ_10, filter->read_ok);
__set_bit(READ_12, filter->read_ok);
__set_bit(READ_16, filter->read_ok);
__set_bit(READ_BUFFER, filter->read_ok);
__set_bit(READ_DEFECT_DATA, filter->read_ok);
__set_bit(READ_CAPACITY, filter->read_ok);
__set_bit(READ_LONG, filter->read_ok);
__set_bit(INQUIRY, filter->read_ok);
__set_bit(MODE_SENSE, filter->read_ok);
__set_bit(MODE_SENSE_10, filter->read_ok);
__set_bit(LOG_SENSE, filter->read_ok);
__set_bit(START_STOP, filter->read_ok);
__set_bit(GPCMD_VERIFY_10, filter->read_ok);
__set_bit(VERIFY_16, filter->read_ok);
__set_bit(REPORT_LUNS, filter->read_ok);
__set_bit(SERVICE_ACTION_IN, filter->read_ok);
__set_bit(RECEIVE_DIAGNOSTIC, filter->read_ok);
__set_bit(MAINTENANCE_IN_CMD, filter->read_ok);
__set_bit(GPCMD_READ_BUFFER_CAPACITY, filter->read_ok);

/* Audio CD commands */
__set_bit(GPCMD_PLAY_CD, filter->read_ok);
__set_bit(GPCMD_PLAY_AUDIO_10, filter->read_ok);
__set_bit(GPCMD_PLAY_AUDIO_MSF, filter->read_ok);
__set_bit(GPCMD_PLAY_AUDIO_TI, filter->read_ok);
__set_bit(GPCMD_PAUSE_RESUME, filter->read_ok);

/* CD/DVD data reading */
__set_bit(GPCMD_READ_CD, filter->read_ok);
__set_bit(GPCMD_READ_CD_MSF, filter->read_ok);
__set_bit(GPCMD_READ_DISC_INFO, filter->read_ok);
__set_bit(GPCMD_READ_CDVD_CAPACITY, filter->read_ok);
__set_bit(GPCMD_READ_DVD_STRUCTURE, filter->read_ok);
__set_bit(GPCMD_READ_HEADER, filter->read_ok);
__set_bit(GPCMD_READ_TRACK_RZONE_INFO, filter->read_ok);
__set_bit(GPCMD_READ_SUBCHANNEL, filter->read_ok);
__set_bit(GPCMD_READ_TOC_PMA_ATIP, filter->read_ok);
__set_bit(GPCMD_REPORT_KEY, filter->read_ok);
__set_bit(GPCMD_SCAN, filter->read_ok);
__set_bit(GPCMD_GET_CONFIGURATION, filter->read_ok);
__set_bit(GPCMD_READ_FORMAT_CAPACITIES, filter->read_ok);
__set_bit(GPCMD_GET_EVENT_STATUS_NOTIFICATION, filter->read_ok);
__set_bit(GPCMD_GET_PERFORMANCE, filter->read_ok);
__set_bit(GPCMD_SEEK, filter->read_ok);
__set_bit(GPCMD_STOP_PLAY_SCAN, filter->read_ok);

/* Basic writing commands */
__set_bit(WRITE_6, filter->write_ok);
__set_bit(WRITE_10, filter->write_ok);
__set_bit(WRITE_VERIFY, filter->write_ok);
__set_bit(WRITE_12, filter->write_ok);
__set_bit(WRITE_VERIFY_12, filter->write_ok);
__set_bit(WRITE_16, filter->write_ok);
__set_bit(WRITE_LONG, filter->write_ok);
__set_bit(WRITE_LONG_2, filter->write_ok);
__set_bit(ERASE, filter->write_ok);
__set_bit(GPCMD_MODE_SELECT_10, filter->write_ok);
__set_bit(MODE_SELECT, filter->write_ok);
__set_bit(LOG_SELECT, filter->write_ok);
__set_bit(GPCMD_BLANK, filter->write_ok);
__set_bit(GPCMD_CLOSE_TRACK, filter->write_ok);
__set_bit(GPCMD_FLUSH_CACHE, filter->write_ok);
__set_bit(GPCMD_FORMAT_UNIT, filter->write_ok);
__set_bit(GPCMD_REPAIR_RZONE_TRACK, filter->write_ok);
__set_bit(GPCMD_RESERVE_RZONE_TRACK, filter->write_ok);
__set_bit(GPCMD_SEND_DVD_STRUCTURE, filter->write_ok);
__set_bit(GPCMD_SEND_EVENT, filter->write_ok);
__set_bit(GPCMD_SEND_KEY, filter->write_ok);
__set_bit(GPCMD_SEND_OPC, filter->write_ok);
__set_bit(GPCMD_SEND_CUE_SHEET, filter->write_ok);
__set_bit(GPCMD_SET_SPEED, filter->write_ok);
__set_bit(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL, filter->write_ok);
__set_bit(GPCMD_LOAD_UNLOAD, filter->write_ok);
__set_bit(GPCMD_SET_STREAMING, filter->write_ok);
}

int blk_register_filter(struct gendisk *disk)
{
int ret;
struct blk_scsi_cmd_filter *filter = &disk->cmd_filter;
struct blk_scsi_cmd_filter *filter = &disk->queue->cmd_filter;
struct kobject *parent = kobject_get(disk->holder_dir->parent);

if (!parent)
return -ENODEV;

ret = kobject_init_and_add(&filter->kobj, &rcf_ktype, parent,
"%s", "cmd_filter");
"%s", "cmd_filter");

if (ret < 0)
return ret;

rcf_set_defaults(filter);
return 0;
}

void blk_unregister_filter(struct gendisk *disk)
{
struct blk_scsi_cmd_filter *filter = &disk->cmd_filter;
struct blk_scsi_cmd_filter *filter = &disk->queue->cmd_filter;

kobject_put(&filter->kobj);
kobject_put(disk->holder_dir->parent);
Expand Down
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