Re: [PATCH 2/2] block: defer the use of inline biovecs for discardrequests

From: Jens Axboe
Date: Mon Jun 28 2010 - 08:34:20 EST

On 2010-06-26 21:56, Mike Snitzer wrote:
> Don't alloc discard bio with a biovec in blkdev_issue_discard. Doing so
> means bio_has_data() will not be true until the SCSI layer adds the
> payload to the discard request via blk_add_request_payload.

Sorry, this looks horrible. What is the point of this?!

> bio_{enable,disable}_inline_vecs are not expected to be widely used so
> they were exported using EXPORT_SYMBOL_GPL.

Never export anything that doesn't have an in-kernel modular user.

> This patch avoids the need for the following VM accounting fix for
> discards:
> NOTE: Jens, you said you applied Tao Ma's fix but I cannot see it in
> your linux-2.6-block's for-next or for-2.6.36... as such I didn't revert
> it in this patch.

It's in the for-linus branch, that is stuff headed for the current

Jens Axboe

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at