Messages in this thread | | | Date | Mon, 27 Jul 2015 02:45:30 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH v7 4/6] block: loop: prepare for supporing direct IO |
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On Mon, Jul 27, 2015 at 05:41:57AM -0400, Ming Lei wrote: > > Why the hardcoded value? I suspect this should be more like: > > > > if (dio && inode->i_sb->s_bdev && > > (lo->lo_offset & (bdev_io_min(inode->i_sb->s_bdev) - 1)) != 0) > > dio = false; > > The above can't work if the backing device has a bigger sector size > (such as 4K), that is why loop's direct-io requires 512 min_io_size of > backing device.
Why doesn't it work? If the backing device sector size is 4k and lo_offset is 0 or a multiple of 4k it should allow direct I/O, and my code sniplet will allow that.
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