Commit bcd069bb authored by Martin K. Petersen's avatar Martin K. Petersen Committed by Jens Axboe
Browse files

scsi: sd: Remove LBPRZ dependency for discards 



Separating discards and zeroout operations allows us to remove the LBPRZ
block zeroing constraints from discards and honor the device preferences
for UNMAP commands.

If supported by the device, we'll also choose UNMAP over one of the
WRITE SAME variants for discards.

Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent e6bd9312

drivers/scsi/sd.c

+6 −19
Original line number Diff line number Diff line
@@ -685,24 +685,11 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode) 
	unsigned int logical_block_size = sdkp->device->sector_size;

	unsigned int max_blocks = 0;



	/*

	 * When LBPRZ is reported, discard alignment and granularity

	 * must be fixed to the logical block size. Otherwise the block

	 * layer will drop misaligned portions of the request which can

	 * lead to data corruption. If LBPRZ is not set, we honor the

	 * device preference.

	 */

	if (sdkp->lbprz) {

		q->limits.discard_alignment = 0;

		q->limits.discard_granularity = logical_block_size;

	} else {

		q->limits.discard_alignment = sdkp->unmap_alignment *

			logical_block_size;

	q->limits.discard_alignment =

		sdkp->unmap_alignment * logical_block_size;

	q->limits.discard_granularity =

		max(sdkp->physical_block_size,

		    sdkp->unmap_granularity * logical_block_size);

	}



	sdkp->provisioning_mode = mode;



	switch (mode) {
@@ -2842,7 +2829,7 @@ static void sd_read_block_limits(struct scsi_disk *sdkp) 
				sd_config_discard(sdkp, SD_LBP_WS16);



		} else {	/* LBP VPD page tells us what to use */

			if (sdkp->lbpu && sdkp->max_unmap_blocks && !sdkp->lbprz)

			if (sdkp->lbpu && sdkp->max_unmap_blocks)

				sd_config_discard(sdkp, SD_LBP_UNMAP);

			else if (sdkp->lbpws)

				sd_config_discard(sdkp, SD_LBP_WS16);

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