From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse Subject: [PATCH 6/7] [MTD] [FTL] Support 'discard sectors' operation. Date: Sat, 09 Aug 2008 17:33:02 +0100 Message-ID: <1218299582.26926.109.camel@pmac.infradead.org> References: <1218299181.26926.88.camel@pmac.infradead.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Ric Wheeler , linux-fsdevel@vger.kernel.org, gilad@codefidence.com, matthew@wil.cx To: Jens Axboe Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:55123 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751320AbYHIQd2 (ORCPT ); Sat, 9 Aug 2008 12:33:28 -0400 In-Reply-To: <1218299181.26926.88.camel@pmac.infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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 --- drivers/mtd/ftl.c | 24 ++++++++++++++++++++++++ 1 files changed, 24 insertions(+), 0 deletions(-) diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c index f34f20c..9bf581c 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, -- 1.5.5.1 -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation