On Mon, Feb 07, 2011 at 12:53:14AM -0800, per...@pluto.rain.com wrote: > Noticed while digging through devfs_read_f() and devfs_write_f() in > the course of investigating some unexpected (by me) geom behavior: > > ... > int ioflag, error, resid; > ... > resid = uio->uio_resid; > ... > if (uio->uio_resid != resid || ... > > IOW resid (an int) is being assigned from and compared with > uio->uio_resid (an ssize_t). > > I suppose it's probably harmless on any arch where an (int) is at > least as large as an (ssize_t), but strictly speaking it does look > like a bug -- or am I missing something?
The only consequence of resid truncating uio_resid would be failure to update access time for the devfs node, which is probably not a big issue. In fact, HEAD cannot generate request for i/o greater than 4GB anyway. The type of uio_resid was increased from int to ssize_t to not break the KBI and ease indended fix to support full size_t arguments for read(2)/write(2). The change requires lots of careful review, and thus stalled. I integrated your fix into the patch, see http://people.freebsd.org/~kib/misc/uio_resid.4.patch
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