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Commit f2e18982 authored by Fengguang Wu's avatar Fengguang Wu Committed by Linus Torvalds
Browse files

readahead: remove the limit max_sectors_kb imposed on max_readahead_kb 



Remove the size limit max_sectors_kb imposed on max_readahead_kb.

The size restriction is unreasonable.  Especially when max_sectors_kb cannot
grow larger than max_hw_sectors_kb, which can be rather small for some disk
drives.

Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarFengguang Wu <wfg@mail.ustc.edu.cn>
Acked-by: default avatarJens Axboe <jens.axboe@oracle.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 535443f5

block/ll_rw_blk.c

+0 −9
Original line number Diff line number Diff line
@@ -3928,7 +3928,6 @@ queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) 
			max_hw_sectors_kb = q->max_hw_sectors >> 1,

			page_kb = 1 << (PAGE_CACHE_SHIFT - 10);

	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);

	int ra_kb;



	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)

		return -EINVAL;
@@ -3937,14 +3936,6 @@ queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) 
	 * values synchronously:

	 */

	spin_lock_irq(q->queue_lock);

	/*

	 * Trim readahead window as well, if necessary:

	 */

	ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);

	if (ra_kb > max_sectors_kb)

		q->backing_dev_info.ra_pages =

				max_sectors_kb >> (PAGE_CACHE_SHIFT - 10);



	q->max_sectors = max_sectors_kb << 1;

	spin_unlock_irq(q->queue_lock);