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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 <simon.kagstrom@netinsight.net>
Reviewed-by: Anders Grafstrom <anders.grafstrom@netinsight.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Simon Kagstrom 2009-10-29 13:41:11 +01:00 committed by David Woodhouse
parent a15b124fc4
commit be95745f01
1 changed files with 44 additions and 18 deletions
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62
drivers/mtd/mtdoops.c
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@ -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);
}