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FAILED: patch "[PATCH] block: don't deal with discard limit in" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message Nov 9, 2018

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The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 744889b7cbb56a64f957e65ade7cb65fe3f35714 Mon Sep 17 00:00:00 2001

From: Ming Lei <[email protected]>
Date: Fri, 12 Oct 2018 15:53:10 +0800
Subject: [PATCH] block: don't deal with discard limit in
blkdev_issue_discard()

blk_queue_split() does respect this limit via bio splitting, so no need to do that in blkdev_issue_discard(), then we can align to normal bio submit(bio_add_page() & submit_bio()).

More importantly, this patch fixes one issue introduced in a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks"), in which zero discard bio may be generated in case of zero alignment.

Fixes a22c4d7e34402ccdf3 ("block: re-add discard_granularity and alignment checks")
Cc [email protected]
Cc Ming Lin <[email protected]>
Cc Mike Snitzer <[email protected]>
Cc Christoph Hellwig <[email protected]>
Cc Xiao Ni <[email protected]>
Tested-by Mariusz Dabrowski <[email protected]>
Signed-off-by Ming Lei <[email protected]>
Signed-off-by Jens Axboe <[email protected]>
block/blk-lib.c +2 -26
index d1b9dd03da25..bbd44666f2b5 100644
@@ -29,9 +29,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 {
 	struct request_queue *q = bdev_get_queue(bdev);
 	struct bio *bio = *biop;
-	unsigned int granularity;
 	unsigned int op;
-	int alignment;
 	sector_t bs_mask;
 
 	if (!q)

@@ -54,38 +52,16 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 	if ((sector | nr_sects) & bs_mask)
 		return -EINVAL;
 
-	/* Zero-sector (unknown) and one-sector granularities are the same.  */
-	granularity = max(q->limits.discard_granularity >> 9, 1U);
-	alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
-
 	while (nr_sects) {
-		unsigned int req_sects;
-		sector_t end_sect, tmp;
+		unsigned int req_sects = nr_sects;
+		sector_t end_sect;
 
-		/*
-		 * Issue in chunks of the user defined max discard setting,
-		 * ensuring that bi_size doesn't overflow
-		 */
-		req_sects = min_t(sector_t, nr_sects,
-					q->limits.max_discard_sectors);
 		if (!req_sects)
 			goto fail;
 		if (req_sects > UINT_MAX >> 9)
 			req_sects = UINT_MAX >> 9;
 
-		/*
-		 * If splitting a request, and the next starting sector would be
-		 * misaligned, stop the discard at the previous aligned sector.
-		 */
 		end_sect = sector + req_sects;
-		tmp = end_sect;
-		if (req_sects < nr_sects &&
-		    sector_div(tmp, granularity) != alignment) {
-			end_sect = end_sect - alignment;
-			sector_div(end_sect, granularity);
-			end_sect = end_sect * granularity + alignment;
-			req_sects = end_sect - sector;
-		}
 
 		bio = next_bio(bio, 0, gfp_mask);
 		bio->bi_iter.bi_sector = sector;