[PATCH v6 3/5]: mtdoops: Make page (record) size configurable

Simon Kagstrom
2009-10-14T13:41:26Z

The main justification for this is to allow catching long messages
during a panic, where the top part might otherwise be lost since moving
to the next block can require a flash erase.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Reviewed-by: Anders Grafstrom <anders.grafstrom@netinsight.net>
---
ChangeLog:
Review comments from Anders Grafström and own fixes:
* Set record_size parameter permissions to 0400
* Don't require power-of-two sizes

drivers/mtd/mtdoops.c | 76 ++++++++++++++++++++++++++++--------------------
1 files changed, 44 insertions(+), 32 deletions(-)

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index 08627c2..2870a11 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -34,7 +34,11 @@
#include <linux/mtd/mtd.h>

#define MTDOOPS_KERNMSG_MAGIC 0x5d005d00
-#define OOPS_PAGE_SIZE 4096
+
+static unsigned long record_size = 4096;
+module_param(record_size, ulong, 0400);
+MODULE_PARM_DESC(record_size,
+ "record size for MTD OOPS pages in bytes (default 4096)");

static struct mtdoops_context {
int mtd_index;
@@ -80,8 +84,8 @@ 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;
+ u32 start_page = start_page_offset / record_size;
+ u32 erase_pages = mtd->erasesize / record_size;
struct erase_info erase;
DECLARE_WAITQUEUE(wait, current);
wait_queue_head_t wait_q;
@@ -149,15 +153,15 @@ static void mtdoops_workfunc_erase(struct work_struct *work)
if (!mtd)
return;

- mod = (cxt->nextpage * OOPS_PAGE_SIZE) % mtd->erasesize;
+ mod = (cxt->nextpage * record_size) % mtd->erasesize;
if (mod != 0) {
- cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / OOPS_PAGE_SIZE);
+ cxt->nextpage = cxt->nextpage + ((mtd->erasesize - mod) / record_size);
if (cxt->nextpage >= cxt->oops_pages)
cxt->nextpage = 0;
}

while (mtd->block_isbad) {
- ret = mtd->block_isbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
+ ret = mtd->block_isbad(mtd, cxt->nextpage * record_size);
if (!ret)
break;
if (ret < 0) {
@@ -165,20 +169,20 @@ static void mtdoops_workfunc_erase(struct work_struct *work)
return;
}
badblock:
- printk(KERN_WARNING "mtdoops: bad block at %08x\n",
- cxt->nextpage * OOPS_PAGE_SIZE);
+ printk(KERN_WARNING "mtdoops: bad block at %08lx\n",
+ cxt->nextpage * record_size);
i++;
- cxt->nextpage = cxt->nextpage + (mtd->erasesize / OOPS_PAGE_SIZE);
+ cxt->nextpage = cxt->nextpage + (mtd->erasesize / record_size);
if (cxt->nextpage >= cxt->oops_pages)
cxt->nextpage = 0;
- if (i == cxt->oops_pages / (mtd->erasesize / OOPS_PAGE_SIZE)) {
+ if (i == cxt->oops_pages / (mtd->erasesize / record_size)) {
printk(KERN_ERR "mtdoops: all blocks bad!\n");
return;
}
}

for (j = 0, ret = -1; (j < 3) && (ret < 0); j++)
- ret = mtdoops_erase_block(cxt, cxt->nextpage * OOPS_PAGE_SIZE);
+ ret = mtdoops_erase_block(cxt, cxt->nextpage * record_size);

if (ret >= 0) {
printk(KERN_DEBUG "mtdoops: ready %d, %d\n",
@@ -188,7 +192,7 @@ badblock:
}

if (mtd->block_markbad && ret == -EIO) {
- ret = mtd->block_markbad(mtd, cxt->nextpage * OOPS_PAGE_SIZE);
+ ret = mtd->block_markbad(mtd, cxt->nextpage * record_size);
if (ret < 0) {
printk(KERN_ERR "mtdoops: block_markbad failed, aborting\n");
return;
@@ -203,22 +207,22 @@ static void mtdoops_write(struct mtdoops_context *cxt, int panic)
size_t retlen;
int ret;

- if (cxt->writecount < OOPS_PAGE_SIZE)
+ if (cxt->writecount < record_size)
memset(cxt->oops_buf + cxt->writecount, 0xff,
- OOPS_PAGE_SIZE - cxt->writecount);
+ record_size - cxt->writecount);

if (panic)
- ret = mtd->panic_write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
- OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
+ ret = mtd->panic_write(mtd, cxt->nextpage * record_size,
+ record_size, &retlen, cxt->oops_buf);
else
- ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
- OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
+ ret = mtd->write(mtd, cxt->nextpage * record_size,
+ record_size, &retlen, cxt->oops_buf);

cxt->writecount = 0;

- 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);
+ if (retlen != record_size || ret < 0)
+ printk(KERN_ERR "mtdoops: write failure at %ld (%td of %ld written), error %d\n",
+ cxt->nextpage * record_size, retlen, record_size, ret);
mark_page_used(cxt, cxt->nextpage);

mtdoops_inc_counter(cxt);
@@ -243,10 +247,10 @@ static void find_next_position(struct mtdoops_context *cxt)
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]);
+ ret = mtd->read(mtd, page * record_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);
+ printk(KERN_ERR "mtdoops: read failure at %ld (%td of 8 read), err %d\n",
+ page * record_size, retlen, ret);
continue;
}

@@ -300,7 +304,7 @@ 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);
+ do_div(mtdoops_pages, record_size);

if (cxt->name && !strcmp(mtd->name, cxt->name))
cxt->mtd_index = mtd->index;
@@ -314,7 +318,7 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
return;
}

- if (mtd->erasesize < OOPS_PAGE_SIZE) {
+ if (mtd->erasesize < record_size) {
printk(KERN_ERR "mtdoops: eraseblock size of MTD partition %d too small\n",
mtd->index);
return;
@@ -329,9 +333,9 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
}
cxt->mtd = mtd;
if (mtd->size > INT_MAX)
- cxt->oops_pages = INT_MAX / OOPS_PAGE_SIZE;
+ cxt->oops_pages = INT_MAX / record_size;
else
- cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
+ cxt->oops_pages = (int)mtd->size / record_size;

find_next_position(cxt);

@@ -408,15 +412,15 @@ mtdoops_console_write(struct console *co, const char *s, unsigned int count)
cxt->writecount = 8;
}

- if (count + cxt->writecount > OOPS_PAGE_SIZE)
- count = OOPS_PAGE_SIZE - cxt->writecount;
+ if (count + cxt->writecount > record_size)
+ count = record_size - cxt->writecount;

memcpy(cxt->oops_buf + cxt->writecount, s, count);
cxt->writecount += count;

spin_unlock_irqrestore(&cxt->writecount_lock, flags);

- if (cxt->writecount == OOPS_PAGE_SIZE)
+ if (cxt->writecount == record_size)
mtdoops_console_sync();
}

@@ -455,8 +459,16 @@ static int __init mtdoops_console_init(void)
{
struct mtdoops_context *cxt = &oops_cxt;

+ if ((record_size & 4095) != 0) {
+ printk(KERN_ERR "mtdoops: record_size must be a multiple of 4096\n");
+ return -EINVAL;
+ }
+ if (record_size < 4096) {
+ printk(KERN_ERR "mtdoops: record_size must be over 4096 bytes\n");
+ return -EINVAL;
+ }
cxt->mtd_index = -1;
- cxt->oops_buf = vmalloc(OOPS_PAGE_SIZE);
+ cxt->oops_buf = vmalloc(record_size);
if (!cxt->oops_buf) {
printk(KERN_ERR "mtdoops: failed to allocate buffer workspace\n");
return -ENOMEM;
--
1.6.0.4