Re: [Qemu-devel] [PATCH v4 3/8] block: Add blk_get_opt_transfer()

2017-02-21 Thread Marc-André Lureau
On Tue, Feb 21, 2017 at 6:45 AM Eric Blake wrote: > The NBD protocol would like to advertise the optimal I/O > size to the client; but it would be a layering violation to > peek into blk_bs(blk)->bl, when we only have a BB. > > This copies the existing blk_get_max_transfer()

[Qemu-devel] [PATCH v4 3/8] block: Add blk_get_opt_transfer()

2017-02-20 Thread Eric Blake
The NBD protocol would like to advertise the optimal I/O size to the client; but it would be a layering violation to peek into blk_bs(blk)->bl, when we only have a BB. This copies the existing blk_get_max_transfer() in reading a value from the top BDS; where that value was picked via