From patchwork Wed Oct 14 13:40:49 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v6,1/5] : mtdoops: avoid erasing already empty areas Date: Wed, 14 Oct 2009 03:40:49 -0000 From: Simon Kagstrom X-Patchwork-Id: 35965 Message-Id: <20091014154049.7ee27f14@marrow.netinsight.se> To: Linus Torvalds , linux-mtd Cc: Artem Bityutskiy , LKML , "Koskinen Aaro \(Nokia-D/Helsinki\)" , Ingo Molnar , David Woodhouse , Andrew Morton , Alan Cox After having scanned the entire mtdoops area, mtdoops will erase it if there are no mtdoops headers in it. However, empty and already erased areas (i.e., without mtdoops headers) will therefore also be erased at each startup. This patch counts the number of unclean pages (neither empty nor with the mtdoops header) and only erases if no headers are found and the area is still unclean. Signed-off-by: Simon Kagstrom --- drivers/mtd/mtdoops.c | 18 ++++++++++++++---- 1 files changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index 18c6c96..c785e1a 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -225,7 +225,7 @@ static void mtdoops_workfunc_write(struct work_struct *work) static void find_next_position(struct mtdoops_context *cxt) { struct mtd_info *mtd = cxt->mtd; - int ret, page, maxpos = 0; + int ret, page, maxpos = 0, unclean_pages = 0; u32 count[2], maxcount = 0xffffffff; size_t retlen; @@ -237,10 +237,13 @@ static void find_next_position(struct mtdoops_context *cxt) continue; } - if (count[1] != MTDOOPS_KERNMSG_MAGIC) - continue; if (count[0] == 0xffffffff) continue; + if (count[1] != MTDOOPS_KERNMSG_MAGIC) { + /* Page is neither clean nor empty */ + unclean_pages++; + continue; + } if (maxcount == 0xffffffff) { maxcount = count[0]; maxpos = page; @@ -259,7 +262,14 @@ static void find_next_position(struct mtdoops_context *cxt) if (maxcount == 0xffffffff) { cxt->nextpage = 0; cxt->nextcount = 1; - schedule_work(&cxt->work_erase); + if (unclean_pages != 0) { + printk(KERN_INFO "mtdoops: cleaning area\n"); + schedule_work(&cxt->work_erase); + } else { + printk(KERN_DEBUG "mtdoops: ready %d, %d (clean)\n", + cxt->nextpage, cxt->nextcount); + cxt->ready = 1; + } return; }