From fdc53971bce56d299cb5f1f06ecbff30b34cbaf2 Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Tue, 5 Aug 2008 18:08:56 +0100 Subject: [PATCH] Support 'discard sectors' operation. We can benefit from knowing that the file system no longer cares about the contents of certain sectors, by throwing them away immediately and then never having to garbage collect them, and using the extra free space to make our operations more efficient. Do so. Signed-off-by: David Woodhouse Signed-off-by: Jens Axboe --- drivers/mtd/ftl.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c index f34f20c7891..9bf581c4f74 100644 --- a/drivers/mtd/ftl.c +++ b/drivers/mtd/ftl.c @@ -1005,6 +1005,29 @@ static int ftl_writesect(struct mtd_blktrans_dev *dev, return ftl_write((void *)dev, buf, block, 1); } +static int ftl_discardsect(struct mtd_blktrans_dev *dev, + unsigned long sector, unsigned nr_sects) +{ + partition_t *part = (void *)dev; + uint32_t bsize = 1 << part->header.EraseUnitSize; + + DEBUG(1, "FTL erase sector %ld for %d sectors\n", + sector, nr_sects); + + while (nr_sects) { + uint32_t old_addr = part->VirtualBlockMap[sector]; + if (old_addr != 0xffffffff) { + part->VirtualBlockMap[sector] = 0xffffffff; + part->EUNInfo[old_addr/bsize].Deleted++; + if (set_bam_entry(part, old_addr, 0)) + return -EIO; + } + nr_sects--; + sector++; + } + + return 0; +} /*====================================================================*/ static void ftl_freepart(partition_t *part) @@ -1069,6 +1092,7 @@ static struct mtd_blktrans_ops ftl_tr = { .blksize = SECTOR_SIZE, .readsect = ftl_readsect, .writesect = ftl_writesect, + .discard = ftl_discardsect, .getgeo = ftl_getgeo, .add_mtd = ftl_add_mtd, .remove_dev = ftl_remove_dev, -- 2.41.1