3.16.85-rc1 review patch. If anyone has any objections, please let me know.
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From: Akinobu Mita akinobu.mita@gmail.com
commit 46f69e6a6bbbf3858617c8729e31895846c15a79 upstream.
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@gmail.com Acked by: Douglas Gilbert dgilbert@interlog.com Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/scsi/sg.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
--- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -865,6 +865,15 @@ static int srp_done(Sg_fd *sfp, Sg_reque 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) { @@ -1004,7 +1013,7 @@ sg_ioctl(struct file *filp, unsigned int 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; @@ -1014,7 +1023,7 @@ sg_ioctl(struct file *filp, unsigned int 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); @@ -1154,7 +1163,7 @@ sg_ioctl(struct file *filp, unsigned int 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, @@ -2170,7 +2179,7 @@ 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));