CVE-2025-21832

In the Linux kernel, the following vulnerability has been resolved:

block: don't revert iter for -EIOCBQUEUED

blkdevreaditer() has a few odd checks, like gating the position and count adjustment on whether or not the result is bigger-than-or-equal to zero (where bigger than makes more sense), and not checking the return value of blkdevdirectIO() before doing an ioviterrevert(). The latter can lead to attempting to revert with a negative value, which when passed to ioviterrevert() as an unsigned value will lead to throwing a WARNON() because unroll is bigger than MAXRW_COUNT.

Be sane and don't revert for -EIOCBQUEUED, like what is done in other spots.