Commit d369735e authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

ublk: fix ublk_ch_mmap() for 64K page size 



In ublk_ch_mmap(), queue id is calculated in the following way:

	(vma->vm_pgoff << PAGE_SHIFT) / `max_cmd_buf_size`

'max_cmd_buf_size' is equal to

	`UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc)`

and UBLK_MAX_QUEUE_DEPTH is 4096 and part of UAPI, so 'max_cmd_buf_size'
is always page aligned in 4K page size kernel. However, it isn't true in
64K page size kernel.

Fixes the issue by always rounding up 'max_cmd_buf_size' with PAGE_SIZE.

Cc: stable@vger.kernel.org
Fixes: 71f28f31 ("ublk_drv: add io_uring based userspace block driver")
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241111110718.1394001-1-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b2113eda

drivers/block/ublk_drv.c

+12 −3
Original line number Diff line number Diff line
@@ -669,12 +669,21 @@ static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id) 
	return ublk_get_queue(ub, q_id)->io_cmd_buf;

}



static inline int __ublk_queue_cmd_buf_size(int depth)

{

	return round_up(depth * sizeof(struct ublksrv_io_desc), PAGE_SIZE);

}



static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id)

{

	struct ublk_queue *ubq = ublk_get_queue(ub, q_id);



	return round_up(ubq->q_depth * sizeof(struct ublksrv_io_desc),

			PAGE_SIZE);

	return __ublk_queue_cmd_buf_size(ubq->q_depth);

}



static int ublk_max_cmd_buf_size(void)

{

	return __ublk_queue_cmd_buf_size(UBLK_MAX_QUEUE_DEPTH);

}



/*
@@ -1358,7 +1367,7 @@ static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma) 
{

	struct ublk_device *ub = filp->private_data;

	size_t sz = vma->vm_end - vma->vm_start;

	unsigned max_sz = UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc);

	unsigned max_sz = ublk_max_cmd_buf_size();

	unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT;

	int q_id, ret = 0;