Re: [PATCH] block: don't optimize for non-cloned bio in bio_get_last_bvec()

From: Jens Axboe
Date: Sat Mar 12 2016 - 23:20:54 EST

On 03/12/2016 08:58 PM, Jens Axboe wrote:
On 03/12/2016 07:56 AM, Ming Lei wrote:
For !BIO_CLONED bio, we can use .bi_vcnt safely, but it
doesn't mean we can just simply return .bi_io_vec[.bi_vcnt - 1]
because the start postion may have been moved in the middle of
the bvec, such as splitting in the middle of bvec.

Added and tested.

And Ming, let's not get a repeat of this situation. For critical fixes, it has to be spot on for post -rc1, especially for code that is notoriously difficult to get right. Fixes are obviously fine, but it has to be just enough to fix the regression, no more. This has been too lax, I expect this to improve.

Jens Axboe