block: don't revert iter for -EIOCBQUEUED

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: block: don't revert iter for -EIOCBQUEUED blkdev_read_iter() 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 blkdev_direct_IO() before doing an iov_iter_revert(). The latter can lead to attempting to revert with a negative value, which when passed to iov_iter_revert() as an unsigned value will lead to throwing a WARN_ON() because unroll is bigger than MAX_RW_COUNT. Be sane and don't revert for -EIOCBQUEUED, like what is done in other spots.

References

• https://git.kernel.org/stable/c/6c26619effb1b4cb7d20b4e666ab8f71f6a53ccb
• https://git.kernel.org/stable/c/84671b0630ccb46ae9f1f99a45c7d63ffcd6a474
• https://git.kernel.org/stable/c/68f16d3034a06661245ecd22f0d586a8b4e7c473
• https://git.kernel.org/stable/c/a58f136bad29f9ae721a29d98c042fddbee22f77
• https://git.kernel.org/stable/c/b13ee668e8280ca5b07f8ce2846b9957a8a10853