mtd: mtdoops: make record size configurable

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>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 43 insertions, 31 deletions

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index b016eee18657..64772dc0ea2b 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -37,7 +37,11 @@
 #define MTDOOPS_MAX_MTD_SIZE (8 * 1024 * 1024)
 
 #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;
@@ -83,8 +87,8 @@ 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;
@@ -152,15 +156,15 @@ 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) {
@@ -168,20 +172,20 @@ 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",
@@ -191,7 +195,7 @@ 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;
@@ -206,22 +210,22 @@ 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);
@@ -246,10 +250,10 @@ 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;
                 }
 
@@ -293,7 +297,7 @@ 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;
@@ -307,7 +311,7 @@ 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;
@@ -328,7 +332,7 @@ static void mtdoops_notify_add(struct mtd_info *mtd)
         }
 
         cxt->mtd = mtd;
-        cxt->oops_pages = (int)mtd->size / OOPS_PAGE_SIZE;
+        cxt->oops_pages = (int)mtd->size / record_size;
         find_next_position(cxt);
         printk(KERN_INFO "mtdoops: Attached to MTD device %d\n", mtd->index);
 }
@@ -403,15 +407,15 @@ 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();
 }
 
@@ -450,8 +454,16 @@ 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;