[PATCH v2 1/3]: mtdoops: Keep track of clean/dirty mtdoops pages in an array

Simon Kagstrom
2009-10-08T14:44:51Z

This patch makes mtdoops keep track of clean/dirty 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.
---
drivers/mtd/mtdoops.c | 50 +++++++++++++++++++++++++++++-------------------
1 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index ac67833..19632d5 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;
+ u8 *oops_page_dirty;
char *name;

void *oops_buf;
@@ -60,12 +61,17 @@ static void mtdoops_erase_callback(struct erase_info *done)
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 +96,15 @@ 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 clean */
+ for (page = start_page; page < start_page + erase_pages; page++)
+ cxt->oops_page_dirty[page] = 0;
+
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;
@@ -107,18 +112,7 @@ 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 (cxt->oops_page_dirty[cxt->nextpage]) {
schedule_work(&cxt->work_erase);
return;
}
@@ -169,7 +163,7 @@ 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", cxt->nextpage, cxt->nextcount);
@@ -230,13 +224,17 @@ static void find_next_position(struct mtdoops_context *cxt)
size_t retlen;

for (page = 0; page < cxt->oops_pages; page++) {
+ /* Assume it's dirty */
+ cxt->oops_page_dirty[page] = 1;
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", page * OOPS_PAGE_SIZE, retlen, ret);
continue;
}
-
+ if (count[0] == 0xffffffff && count[1] == 0xffffffff)
+ cxt->oops_page_dirty[page] = 0;
if (count[1] != MTDOOPS_KERNMSG_MAGIC)
continue;
if (count[0] == 0xffffffff)
@@ -273,6 +271,9 @@ 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 +293,12 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
return;
}

+ cxt->oops_page_dirty = vmalloc(mtdoops_pages);
+ if (!cxt->oops_page_dirty) {
+ printk(KERN_ERR "Could not allocate page array (%Ld bytes)\n",
+ mtdoops_pages);
+ return;
+ }
cxt->mtd = mtd;
if (mtd->size > INT_MAX)
cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
@@ -428,6 +435,7 @@ static int __init mtdoops_console_init(void)
printk(KERN_ERR "Failed to allocate mtdoops buffer workspace\n");
return -ENOMEM;
}
+ cxt->oops_page_dirty = NULL;

INIT_WORK(&cxt->work_erase, mtdoops_workfunc_erase);
INIT_WORK(&cxt->work_write, mtdoops_workfunc_write);
@@ -445,6 +453,8 @@ static void __exit mtdoops_console_exit(void)
unregister_console(&mtdoops_console);
kfree(cxt->name);
vfree(cxt->oops_buf);
+ if (cxt->oops_page_dirty)
+ vfree(cxt->oops_page_dirty);
}

--
1.6.0.4