From: Simon Kagstrom Date: Thu, 29 Oct 2009 12:41:11 +0000 (+0100) Subject: mtd: mtdoops: keep track of used/unused pages in an array X-Git-Tag: firefly_0821_release~9833^2~3646^2~11 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=be95745f01677245a061a8f51473ef5ec8ad008e;p=firefly-linux-kernel-4.4.55.git mtd: mtdoops: keep track of used/unused pages in an array This patch makes mtdoops keep track of used/unused pages in an array instead of scanning the flash after a write. The advantage with this approach is that it avoids calling mtd->read on a panic, which is not possible for all mtd drivers. Signed-off-by: Simon Kagstrom Reviewed-by: Anders Grafstrom Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c index c383add060d8..06c538249455 100644 --- a/drivers/mtd/mtdoops.c +++ b/drivers/mtd/mtdoops.c @@ -44,6 +44,7 @@ static struct mtdoops_context { int oops_pages; int nextpage; int nextcount; + unsigned long *oops_page_used; char *name; void *oops_buf; @@ -54,18 +55,38 @@ static struct mtdoops_context { int writecount; } oops_cxt; +static void mark_page_used(struct mtdoops_context *cxt, int page) +{ + set_bit(page, cxt->oops_page_used); +} + +static void mark_page_unused(struct mtdoops_context *cxt, int page) +{ + clear_bit(page, cxt->oops_page_used); +} + +static int page_is_used(struct mtdoops_context *cxt, int page) +{ + return test_bit(page, cxt->oops_page_used); +} + static void mtdoops_erase_callback(struct erase_info *done) { wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv; wake_up(wait_q); } -static int mtdoops_erase_block(struct mtd_info *mtd, int offset) +static int mtdoops_erase_block(struct mtdoops_context *cxt, int offset) { + struct mtd_info *mtd = cxt->mtd; + u32 start_page_offset = mtd_div_by_eb(offset, mtd) * mtd->erasesize; + u32 start_page = start_page_offset / OOPS_PAGE_SIZE; + u32 erase_pages = mtd->erasesize / OOPS_PAGE_SIZE; struct erase_info erase; DECLARE_WAITQUEUE(wait, current); wait_queue_head_t wait_q; int ret; + int page; init_waitqueue_head(&wait_q); erase.mtd = mtd; @@ -90,16 +111,15 @@ static int mtdoops_erase_block(struct mtd_info *mtd, int offset) schedule(); /* Wait for erase to finish. */ remove_wait_queue(&wait_q, &wait); + /* Mark pages as unused */ + for (page = start_page; page < start_page + erase_pages; page++) + mark_page_unused(cxt, page); + return 0; } static void mtdoops_inc_counter(struct mtdoops_context *cxt) { - struct mtd_info *mtd = cxt->mtd; - size_t retlen; - u32 count; - int ret; - cxt->nextpage++; if (cxt->nextpage >= cxt->oops_pages) cxt->nextpage = 0; @@ -107,17 +127,7 @@ static void mtdoops_inc_counter(struct mtdoops_context *cxt) if (cxt->nextcount == 0xffffffff) cxt->nextcount = 0; - ret = mtd->read(mtd, cxt->nextpage * OOPS_PAGE_SIZE, 4, - &retlen, (u_char *) &count); - if (retlen != 4 || (ret < 0 && ret != -EUCLEAN)) { - printk(KERN_ERR "mtdoops: read failure at %d (%td of 4 read), err %d\n", - cxt->nextpage * OOPS_PAGE_SIZE, retlen, ret); - schedule_work(&cxt->work_erase); - return; - } - - /* See if we need to erase the next block */ - if (count != 0xffffffff) { + if (page_is_used(cxt, cxt->nextpage)) { schedule_work(&cxt->work_erase); return; } @@ -168,7 +178,7 @@ badblock: } for (j = 0, ret = -1; (j < 3) && (ret < 0); j++) - ret = mtdoops_erase_block(mtd, cxt->nextpage * OOPS_PAGE_SIZE); + ret = mtdoops_erase_block(cxt, cxt->nextpage * OOPS_PAGE_SIZE); if (ret >= 0) { printk(KERN_DEBUG "mtdoops: ready %d, %d\n", @@ -209,6 +219,7 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic) if (retlen != OOPS_PAGE_SIZE || ret < 0) printk(KERN_ERR "mtdoops: write failure at %d (%td of %d written), error %d\n", cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret); + mark_page_used(cxt, cxt->nextpage); mtdoops_inc_counter(cxt); } @@ -230,6 +241,8 @@ static void find_next_position(struct mtdoops_context *cxt) size_t retlen; for (page = 0; page < cxt->oops_pages; page++) { + /* Assume the page is used */ + mark_page_used(cxt, page); ret = mtd->read(mtd, page * OOPS_PAGE_SIZE, 8, &retlen, (u_char *) &count[0]); if (retlen != 8 || (ret < 0 && ret != -EUCLEAN)) { printk(KERN_ERR "mtdoops: read failure at %d (%td of 8 read), err %d\n", @@ -237,6 +250,8 @@ static void find_next_position(struct mtdoops_context *cxt) continue; } + if (count[0] == 0xffffffff && count[1] == 0xffffffff) + mark_page_unused(cxt, page); if (count[1] != MTDOOPS_KERNMSG_MAGIC) continue; if (count[0] == 0xffffffff) @@ -273,6 +288,9 @@ static void find_next_position(struct mtdoops_context *cxt) static void mtdoops_notify_add(struct mtd_info *mtd) { struct mtdoops_context *cxt = &oops_cxt; + u64 mtdoops_pages = mtd->size; + + do_div(mtdoops_pages, OOPS_PAGE_SIZE); if (cxt->name && !strcmp(mtd->name, cxt->name)) cxt->mtd_index = mtd->index; @@ -292,6 +310,13 @@ static void mtdoops_notify_add(struct mtd_info *mtd) return; } + /* oops_page_used is a bit field */ + cxt->oops_page_used = vmalloc(DIV_ROUND_UP(mtdoops_pages, + BITS_PER_LONG)); + if (!cxt->oops_page_used) { + printk(KERN_ERR "Could not allocate page array\n"); + return; + } cxt->mtd = mtd; if (mtd->size > INT_MAX) cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE; @@ -444,6 +469,7 @@ static void __exit mtdoops_console_exit(void) unregister_console(&mtdoops_console); kfree(cxt->name); vfree(cxt->oops_buf); + vfree(cxt->oops_page_used); }