Hello, We are registering BIO size of our storage device through linux kernel API blk_queue_max_hw_sectors worth of 104K. So max size of BIO that our block device can handle is 104 KB but kernel block layer is sending 256 KB worth of BIO which is more than we are supporting. This issue we are observing in 4.4 and also in latest 4.10.1 kernel release. Until this we had not seen this issue. >From the kernel source code history I came to below things. 4.1 kernel version onwards "nr_pages = min(sdio->pages_in_io, bio_get_nr_vecs(map_bh->b_bdev))" has been removed which (bio_get_nr_vecs) was considering max_sectors_kb of queue which was 104 KB for our device. Presently new code is something like "nr_pages = min(sdio->pages_in_io, BIO_MAX_PAGES)" which is sending 256 KB (BIO_MAX_PAGES) of BIO size to our device which we are not supporting. So from some documentation I found out that 256 KB of bio size is the fix (from 4.x kernel) and that has to support by any drive. Please let me know is there any way to change BIO size worth of 104 KB from 256 KB or any other way to register our BIO size with kernel or any other area to look in to ?. -Umesh
