Re: [PATCH] Allow changing max_sectors_kb above the default 512

From: Jens Axboe
Date: Tue Sep 01 2009 - 16:39:36 EST

On Tue, Sep 01 2009, Nikanth Karthikesan wrote:
> The patch "block: Use accessor functions for queue limits"
> (ae03bf639a5027d27270123f5f6e3ee6a412781d) changed queue_max_sectors_store()
> to use blk_queue_max_sectors() instead of directly assigning the value.
> But blk_queue_max_sectors() differs a bit
> 1. It sets both max_sectors_kb, and max_hw_sectors_kb
> 2. Never allows one to change max_sectors_kb above BLK_DEF_MAX_SECTORS. If one
> specifies a value greater then max_hw_sectors is set to that value but
> max_sectors is set to BLK_DEF_MAX_SECTORS
> I am not sure whether blk_queue_max_sectors() should be changed, as it seems
> to be that way for a long time. And there may be callers dependent on that
> behaviour.
> This patch simply reverts to the older way of directly assigning the value to
> max_sectors as it was before.
> Signed-off-by: Nikanth Karthikesan <knikanth@xxxxxxx>

Good catch! Applied for 2.6.31.

Jens Axboe

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