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-rw-r--r--drivers/mtd/mtdpart.c17
-rw-r--r--include/linux/mtd/mtd.h9
2 files changed, 26 insertions, 0 deletions
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 6174a97..c66902d 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -151,6 +151,20 @@ static int part_write (struct mtd_info *mtd, loff_t to, size_t len,
len, retlen, buf);
}
+static int part_panic_write (struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ struct mtd_part *part = PART(mtd);
+ if (!(mtd->flags & MTD_WRITEABLE))
+ return -EROFS;
+ if (to >= mtd->size)
+ len = 0;
+ else if (to + len > mtd->size)
+ len = mtd->size - to;
+ return part->master->panic_write (part->master, to + part->offset,
+ len, retlen, buf);
+}
+
static int part_write_oob(struct mtd_info *mtd, loff_t to,
struct mtd_oob_ops *ops)
{
@@ -352,6 +366,9 @@ int add_mtd_partitions(struct mtd_info *master,
slave->mtd.read = part_read;
slave->mtd.write = part_write;
+ if (master->panic_write)
+ slave->mtd.panic_write = part_panic_write;
+
if(master->point && master->unpoint){
slave->mtd.point = part_point;
slave->mtd.unpoint = part_unpoint;
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 783fc98..0a13bb3 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -152,6 +152,15 @@ struct mtd_info {
int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf);
int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
+ /* In blackbox flight recorder like scenarios we want to make successful
+ writes in interrupt context. panic_write() is only intended to be
+ called when its known the kernel is about to panic and we need the
+ write to succeed. Since the kernel is not going to be running for much
+ longer, this function can break locks and delay to ensure the write
+ succeeds (but not sleep). */
+
+ int (*panic_write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf);
+
int (*read_oob) (struct mtd_info *mtd, loff_t from,
struct mtd_oob_ops *ops);
int (*write_oob) (struct mtd_info *mtd, loff_t to,
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