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| author | Alan Stern <stern@rowland.harvard.edu> | 2007-02-20 19:01:57 +0300 |
|---|---|---|
| committer | James Bottomley <jejb@mulgrave.il.steeleye.com> | 2007-04-18 02:09:56 +0400 |
| commit | 44ec95425c1d9dce6e4638c29e4362cfb44814e7 (patch) | |
| tree | 6af593dc23a2f7cdb9a0d3ecc46d37aae640c0d8 /block | |
| parent | 1079a2d251f24a7d9e7576217f5f738bc4218337 (diff) | |
| download | linux-44ec95425c1d9dce6e4638c29e4362cfb44814e7.tar.xz | |
[SCSI] sg: cap reserved_size values at max_sectors
This patch (as857) modifies the SG_GET_RESERVED_SIZE and
SG_SET_RESERVED_SIZE ioctls in the sg driver, capping the values at
the device's request_queue's max_sectors value. This will permit
cdrecord to obtain a legal value for the maximum transfer length,
fixing Bugzilla #7026.
The patch also caps the initial reserved_size value. There's no
reason to have a reserved buffer larger than max_sectors, since it
would be impossible to use the extra space.
The corresponding ioctls in the block layer are modified similarly,
and the initial value for the reserved_size is set as large as
possible. This will effectively make it default to max_sectors.
Note that the actual value is meaningless anyway, since block devices
don't have a reserved buffer.
Finally, the BLKSECTGET ioctl is added to sg, so that there will be a
uniform way for users to determine the actual max_sectors value for
any raw SCSI transport.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Douglas Gilbert <dougg@torque.net>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/ll_rw_blk.c | 2 | ||||
| -rw-r--r-- | block/scsi_ioctl.c | 4 |
2 files changed, 5 insertions, 1 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index 38c293b987b7..cf8752abd61a 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -1925,6 +1925,8 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS); blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS); + q->sg_reserved_size = INT_MAX; + /* * all done */ diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c index 65c6a3cba6d6..e83f1dbf7c29 100644 --- a/block/scsi_ioctl.c +++ b/block/scsi_ioctl.c @@ -78,7 +78,9 @@ static int sg_set_timeout(request_queue_t *q, int __user *p) static int sg_get_reserved_size(request_queue_t *q, int __user *p) { - return put_user(q->sg_reserved_size, p); + unsigned val = min(q->sg_reserved_size, q->max_sectors << 9); + + return put_user(val, p); } static int sg_set_reserved_size(request_queue_t *q, int __user *p) |