On 2/13/25 4:00 AM, Ming Lei wrote:
PAGE_SIZE is applied in validating block device queue limits, this way is
^^^^^^^
used?
very fragile and is wrong:
- queue limits are read from hardware, which is often one readonly hardware
^^^^^^^^
read-only?
@@ -1163,6 +1163,8 @@ static inline bool bdev_is_partition(struct block_device *bdev)
enum blk_default_limits {
BLK_MAX_SEGMENTS = 128,
BLK_SAFE_MAX_SECTORS = 255,
+ /* use minimized PAGE_SIZE as min segment size hint */
+ BLK_MIN_SEGMENT_SIZE = 4096,
BLK_MAX_SEGMENT_SIZE = 65536,
BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL,
};
The above comment could be made more clear, e.g. "Use 4 KiB as the
smallest supported DMA segment size limit instead of PAGE_SIZE. This is
important if the page size is larger than 4 KiB since the maximum DMA
segment size for some storage controllers (e.g. eMMC) is 4 KiB."
Anyway:
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
