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Commit 7e83faf3 authored by Sayali Lokhande's avatar Sayali Lokhande
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Revert "sd: Fix rw_max for devices that report an optimal xfer size" 



This reverts 'commit 9814eb75 ("sd: Fix rw_max for devices
that report an optimal xfer size")'.
Max sectors limit for request queue(q->limits.max_sectors) is reduced
from 1024 to 16 sectors by above commit and causing performance impact
(reduced by upto 50%). Hence revert the change to fix the performance
issue observed on 8998.

Change-Id: I9abd2be6c90922ea9de818912f405e0d292a62b8
Signed-off-by: default avatarSayali Lokhande <sayalil@codeaurora.org>
parent a3851309

drivers/scsi/sd.c

+4 −4
Original line number Diff line number Diff line
@@ -2806,10 +2806,10 @@ static int sd_revalidate_disk(struct gendisk *disk) 
	if (sdkp->opt_xfer_blocks &&

	    sdkp->opt_xfer_blocks <= dev_max &&

	    sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS &&

	    logical_to_bytes(sdp, sdkp->opt_xfer_blocks) >= PAGE_CACHE_SIZE) {

		q->limits.io_opt = logical_to_bytes(sdp, sdkp->opt_xfer_blocks);

		rw_max = logical_to_sectors(sdp, sdkp->opt_xfer_blocks);

	} else

	    sdkp->opt_xfer_blocks * sdp->sector_size >= PAGE_CACHE_SIZE)

		rw_max = q->limits.io_opt =

			sdkp->opt_xfer_blocks * sdp->sector_size;

	else

		rw_max = BLK_DEF_MAX_SECTORS;



	/* Combine with controller limits */

drivers/scsi/sd.h

+0 −5
Original line number Diff line number Diff line
@@ -151,11 +151,6 @@ static inline sector_t logical_to_sectors(struct scsi_device *sdev, sector_t blo 
	return blocks << (ilog2(sdev->sector_size) - 9);

}



static inline unsigned int logical_to_bytes(struct scsi_device *sdev, sector_t blocks)

{

	return blocks * sdev->sector_size;

}



/*

 * A DIF-capable target device can be formatted with different

 * protection schemes.  Currently 0 through 3 are defined: