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| author | Alan Stern <stern@rowland.harvard.edu> | 2007-02-20 17:01:57 +0100 |
|---|---|---|
| committer | James Bottomley <jejb@mulgrave.il.steeleye.com> | 2007-04-18 00:09:56 +0200 |
| commit | 44ec95425c1d9dce6e4638c29e4362cfb44814e7 (patch) | |
| tree | 6af593dc23a2f7cdb9a0d3ecc46d37aae640c0d8 /drivers/scsi | |
| parent | [SCSI] BusLogic: stop using check_region (diff) | |
| download | linux-44ec95425c1d9dce6e4638c29e4362cfb44814e7.tar.xz linux-44ec95425c1d9dce6e4638c29e4362cfb44814e7.zip | |
[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 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/sg.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 81e3bc7b02a1..570977cf9efb 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -917,6 +917,8 @@ sg_ioctl(struct inode *inode, struct file *filp, return result; if (val < 0) return -EINVAL; + val = min_t(int, val, + sdp->device->request_queue->max_sectors * 512); if (val != sfp->reserve.bufflen) { if (sg_res_in_use(sfp) || sfp->mmap_called) return -EBUSY; @@ -925,7 +927,8 @@ sg_ioctl(struct inode *inode, struct file *filp, } return 0; case SG_GET_RESERVED_SIZE: - val = (int) sfp->reserve.bufflen; + val = min_t(int, sfp->reserve.bufflen, + sdp->device->request_queue->max_sectors * 512); return put_user(val, ip); case SG_SET_COMMAND_Q: result = get_user(val, ip); @@ -1061,6 +1064,9 @@ sg_ioctl(struct inode *inode, struct file *filp, if (sdp->detached) return -ENODEV; return scsi_ioctl(sdp->device, cmd_in, p); + case BLKSECTGET: + return put_user(sdp->device->request_queue->max_sectors * 512, + ip); default: if (read_only) return -EPERM; /* don't know so take safe approach */ @@ -2339,6 +2345,7 @@ sg_add_sfp(Sg_device * sdp, int dev) { Sg_fd *sfp; unsigned long iflags; + int bufflen; sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN); if (!sfp) @@ -2369,7 +2376,9 @@ sg_add_sfp(Sg_device * sdp, int dev) if (unlikely(sg_big_buff != def_reserved_size)) sg_big_buff = def_reserved_size; - sg_build_reserve(sfp, sg_big_buff); + bufflen = min_t(int, sg_big_buff, + sdp->device->request_queue->max_sectors * 512); + sg_build_reserve(sfp, bufflen); SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: bufflen=%d, k_use_sg=%d\n", sfp->reserve.bufflen, sfp->reserve.k_use_sg)); return sfp; |