This prevents integer overflow when converting the request queue's
max_sectors from sectors to bytes. However, this is a preparation for
extending the data type of max_sectors in struct Scsi_Host and
scsi_host_template. So, it is impossible to happen this integer
overflow for now, because SCSI low-level drivers can not specify
max_sectors greater than 0xffff due to the data type limitation.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: "James E.J. Bottomley" <JBottomley@xxxxxxxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx
---
This patch is a part of the v1 "scsi: increase upper limit for
max_sectors" patch.
drivers/scsi/sg.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index df5e961..e3404d2 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -806,6 +806,15 @@ static int srp_done(Sg_fd *sfp, Sg_request *srp)
return ret;
}
+static int max_sectors_bytes(struct request_queue *q)
+{
+ unsigned int max_sectors = queue_max_sectors(q);
+
+ max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
+
+ return max_sectors << 9;
+}
+
static long
sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
@@ -945,7 +954,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
if (val < 0)
return -EINVAL;
val = min_t(int, val,
- queue_max_sectors(sdp->device->request_queue) * 512);
+ max_sectors_bytes(sdp->device->request_queue));
if (val != sfp->reserve.bufflen) {
if (sg_res_in_use(sfp) || sfp->mmap_called)
return -EBUSY;
@@ -955,7 +964,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
return 0;
case SG_GET_RESERVED_SIZE:
val = min_t(int, sfp->reserve.bufflen,
- queue_max_sectors(sdp->device->request_queue) * 512);
+ max_sectors_bytes(sdp->device->request_queue));
return put_user(val, ip);
case SG_SET_COMMAND_Q:
result = get_user(val, ip);
@@ -1095,7 +1104,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
return -ENODEV;
return scsi_ioctl(sdp->device, cmd_in, p);
case BLKSECTGET:
- return put_user(queue_max_sectors(sdp->device->request_queue) * 512,
+ return put_user(max_sectors_bytes(sdp->device->request_queue),
ip);
case BLKTRACESETUP:
return blk_trace_setup(sdp->device->request_queue,
@@ -2086,7 +2095,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
sg_big_buff = def_reserved_size;
bufflen = min_t(int, sg_big_buff,
- queue_max_sectors(sdp->device->request_queue) * 512);
+ max_sectors_bytes(sdp->device->request_queue));
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));
--
1.9.1
--
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