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Subject[PATCH v3 part1 3/4] sg_io: use different default filters for each device class
Date
Store the filters in a 256-entry array, and pick an appropriate filter
for SCSI devices. Apart from SCSI disks, SG_IO is supported for CCISS,
ide-floppy and virtio-blk devices; TYPE_DISK (which is zero, i.e. the
default) is more appropriate for these devices than TYPE_ROM.

However, all lists are still the same, so there is no semantic change
in this patch.

Cc: stable@gnu.org
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-scsi@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
block/scsi_ioctl.c | 14 +++++---------
drivers/scsi/scsi_scan.c | 2 ++
include/linux/blkdev.h | 2 +-
3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 21ddf17..6e18156 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -35,8 +35,8 @@
#include <scsi/scsi_cmnd.h>

struct blk_cmd_filter {
- unsigned long read_ok[BLK_SCSI_CMD_PER_LONG];
- unsigned long write_ok[BLK_SCSI_CMD_PER_LONG];
+ u32 read_ok[BLK_SCSI_MAX_CMDS];
+ u32 write_ok[BLK_SCSI_MAX_CMDS];
};

static struct blk_cmd_filter blk_default_cmd_filter;
@@ -117,7 +117,7 @@ static int sg_emulated_host(struct request_queue *q, int __user *p)
static void blk_set_cmd_filter_defaults(struct blk_cmd_filter *filter)
{
#define sgio_bitmap_set(cmd, rw) \
- __set_bit((cmd), filter->rw##_ok)
+ filter->rw##_ok[(cmd)] = ~0;

/* Basic read-only commands */
sgio_bitmap_set(TEST_UNIT_READY, read);
@@ -210,16 +210,12 @@ int blk_verify_command(struct request_queue *q,
if (capable(CAP_SYS_RAWIO))
return 0;

- /* if there's no filter set, assume we're filtering everything out */
- if (!filter)
- return -EPERM;
-
/* Anybody who can open the device can do a read-safe command */
- if (test_bit(cmd[0], filter->read_ok))
+ if (filter->read_ok[cmd[0]] & (1 << q->sgio_type))
return 0;

/* Write-safe commands require a writable open */
- if (test_bit(cmd[0], filter->write_ok) && has_write_perm)
+ if (has_write_perm && filter->write_ok[cmd[0]] & (1 << q->sgio_type))
return 0;

return -EPERM;
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 3e58b22..86940f3 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -782,6 +782,8 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
sdev->removable = (inq_result[1] & 0x80) >> 7;
}

+ sdev->request_queue->sgio_type = sdev->type;
+
switch (sdev->type) {
case TYPE_RBC:
case TYPE_TAPE:
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4fca347..5e18969 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -257,7 +257,6 @@ struct blk_queue_tag {
};

#define BLK_SCSI_MAX_CMDS (256)
-#define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))

struct queue_limits {
unsigned long bounce_pfn;
@@ -410,6 +409,7 @@ struct request_queue {
*/
unsigned int sg_timeout;
unsigned int sg_reserved_size;
+ unsigned char sgio_type;
int node;
#ifdef CONFIG_BLK_DEV_IO_TRACE
struct blk_trace *blk_trace;
--
1.8.1.4



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