Commit 63f26496 authored by Akinobu Mita's avatar Akinobu Mita Committed by Jens Axboe

block: fix BLKSECTGET ioctl when max_sectors is greater than USHRT_MAX

BLKSECTGET ioctl loads the request queue's max_sectors as unsigned
short value to the argument pointer.  So if the max_sector is greater
than USHRT_MAX, the upper 16 bits of that is just discarded.

In such case, USHRT_MAX is more preferable than the lower 16 bits of
max_sectors.
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: linux-scsi@vger.kernel.org
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 16e15565
......@@ -663,6 +663,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
fmode_t mode = file->f_mode;
struct backing_dev_info *bdi;
loff_t size;
unsigned int max_sectors;
/*
* O_NDELAY can be altered using fcntl(.., F_SETFL, ..), so we have
......@@ -718,8 +719,9 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
case BLKSSZGET: /* get block device hardware sector size */
return compat_put_int(arg, bdev_logical_block_size(bdev));
case BLKSECTGET:
return compat_put_ushort(arg,
queue_max_sectors(bdev_get_queue(bdev)));
max_sectors = min_t(unsigned int, USHRT_MAX,
queue_max_sectors(bdev_get_queue(bdev)));
return compat_put_ushort(arg, max_sectors);
case BLKROTATIONAL:
return compat_put_ushort(arg,
!blk_queue_nonrot(bdev_get_queue(bdev)));
......
......@@ -278,6 +278,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
struct backing_dev_info *bdi;
loff_t size;
int ret, n;
unsigned int max_sectors;
switch(cmd) {
case BLKFLSBUF:
......@@ -375,7 +376,9 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
case BLKDISCARDZEROES:
return put_uint(arg, bdev_discard_zeroes_data(bdev));
case BLKSECTGET:
return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
max_sectors = min_t(unsigned int, USHRT_MAX,
queue_max_sectors(bdev_get_queue(bdev)));
return put_ushort(arg, max_sectors);
case BLKROTATIONAL:
return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
case BLKRASET:
......
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