1BLK_STACK_LIMITS(9)              Block Devices             BLK_STACK_LIMITS(9)
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NAME

6       blk_stack_limits - adjust queue_limits for stacked devices
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SYNOPSIS

9       int blk_stack_limits(struct queue_limits * t, struct queue_limits * b,
10                            sector_t start);
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ARGUMENTS

13       t
14           the stacking driver limits (top device)
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16       b
17           the underlying queue limits (bottom, component device)
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19       start
20           first data sector within component device
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DESCRIPTION

23       This function is used by stacking drivers like MD and DM to ensure that
24       all component devices have compatible block sizes and alignments. The
25       stacking driver must provide a queue_limits struct (top) and then
26       iteratively call the stacking function for all component (bottom)
27       devices. The stacking function will attempt to combine the values and
28       ensure proper alignment.
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30       Returns 0 if the top and bottom queue_limits are compatible. The top
31       device's block sizes and alignment offsets may be adjusted to ensure
32       alignment with the bottom device. If no compatible sizes and alignments
33       exist, -1 is returned and the resulting top queue_limits will have the
34       misaligned flag set to indicate that the alignment_offset is undefined.
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37Kernel Hackers Manual 3.10         June 2019               BLK_STACK_LIMITS(9)
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