[MTD] Add sync/unblank function to mtdoops

mtdoops wasn't ensuring data was flushed to flash in crash situations
after recent changes in mainline kernels as tracking the
oops_in_progress variable was no longer enough. We can use the "unblank"
console call as a sync call to tell us to write out the buffer though.

Therefore add a sync function to mtdoops and call this when console
unblank events occur.

Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 34 insertions, 23 deletions

diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
index cfc28ab4a3d..62ee2043d04 100644
--- a/drivers/mtd/mtdoops.c
+++ b/drivers/mtd/mtdoops.c
@@ -250,40 +250,50 @@ static void mtdoops_notify_remove(struct mtd_info *mtd)
         flush_scheduled_work();
 }
 
-
-static void
-mtdoops_console_write(struct console *co, const char *s, unsigned int count)
+static void mtdoops_console_sync(void)
 {
-        struct mtdoops_context *cxt = co->data;
+        struct mtdoops_context *cxt = &oops_cxt;
         struct mtd_info *mtd = cxt->mtd;
-        int i, ret;
+        size_t retlen;
+        int ret;
 
         if (!cxt->ready || !mtd)
                 return;
 
-        if (!oops_in_progress && cxt->writecount != 0) {
-                size_t retlen;
-                if (cxt->writecount < OOPS_PAGE_SIZE)
-                        memset(cxt->oops_buf + cxt->writecount, 0xff,
+        if (cxt->writecount == 0)
+                return;
+
+        if (cxt->writecount < OOPS_PAGE_SIZE)
+                memset(cxt->oops_buf + cxt->writecount, 0xff,
                                         OOPS_PAGE_SIZE - cxt->writecount);
 
-                ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
+        ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
                                         OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
-                cxt->ready = 0;
-                cxt->writecount = 0;
-
-                if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
-                        printk(KERN_ERR "mtdoops: Write failure at %d (%d of %d"
-                                " written), err %d.\n",
-                                cxt->nextpage * OOPS_PAGE_SIZE, retlen,
-                                OOPS_PAGE_SIZE, ret);
-
-                ret = mtdoops_inc_counter(cxt);
-                if (ret == 1)
-                        schedule_work(&cxt->work);
+        cxt->ready = 0;
+        cxt->writecount = 0;
+
+        if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
+                printk(KERN_ERR "mtdoops: Write failure at %d (%d of %d written), err %d.\n",
+                        cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);
+
+        ret = mtdoops_inc_counter(cxt);
+        if (ret == 1)
+                schedule_work(&cxt->work);
+}
+
+static void
+mtdoops_console_write(struct console *co, const char *s, unsigned int count)
+{
+        struct mtdoops_context *cxt = co->data;
+        struct mtd_info *mtd = cxt->mtd;
+        int i;
+
+        if (!oops_in_progress) {
+                mtdoops_console_sync();
+                return;
         }
 
-        if (!oops_in_progress)
+        if (!cxt->ready || !mtd)
                 return;
 
         if (cxt->writecount == 0) {
@@ -323,6 +333,7 @@ static struct console mtdoops_console = {
         .name           = "ttyMTD",
         .write          = mtdoops_console_write,
         .setup          = mtdoops_console_setup,
+        .unblank        = mtdoops_console_sync,
         .flags          = CON_PRINTBUFFER,
         .index          = -1,
         .data           = &oops_cxt,