mtd: harmonize mtd_writev usage

This patch makes the 'mtd_writev()' function more usable and logical. We first
teach it to fall-back to the 'default_mtd_writev()' function if the MTD driver
does not define its own '->writev()' method. Then we make block2mtd and JFFS2
just 'mtd_writev()' instead of 'default_mtd_writev()' function. This means we
can now stop exporting 'default_mtd_writev()' and instead, export
'mtd_writev()'. This is much cleaner and more logical, as well as allows us to
get read of another direct 'mtd->writev' access in JFFS2.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

2 files changed, 24 insertions, 4 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index b78f23169d4e..c16f6b4e8938 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -288,7 +288,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
         dev->mtd.flags = MTD_CAP_RAM;
         dev->mtd.erase = block2mtd_erase;
         dev->mtd.write = block2mtd_write;
-        dev->mtd.writev = default_mtd_writev;
+        dev->mtd.writev = mtd_writev;
         dev->mtd.sync = block2mtd_sync;
         dev->mtd.read = block2mtd_read;
         dev->mtd.priv = dev;
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 53a200f722b6..4d0f3e557bd1 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -696,8 +696,8 @@ EXPORT_SYMBOL_GPL(__put_mtd_device);
  * This function returns zero in case of success and a negative error code in
  * case of failure.
  */
-int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
-                       unsigned long count, loff_t to, size_t *retlen)
+static int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
+                              unsigned long count, loff_t to, size_t *retlen)
 {
         unsigned long i;
         size_t totlen = 0, thislen;
@@ -716,7 +716,27 @@ int default_mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
         *retlen = totlen;
         return ret;
 }
-EXPORT_SYMBOL_GPL(default_mtd_writev);
+
+/*
+ * mtd_writev - the vector-based MTD write method
+ * @mtd: mtd device description object pointer
+ * @vecs: the vectors to write
+ * @count: count of vectors in @vecs
+ * @to: the MTD device offset to write to
+ * @retlen: on exit contains the count of bytes written to the MTD device.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,
+               unsigned long count, loff_t to, size_t *retlen)
+{
+        *retlen = 0;
+        if (!mtd->writev)
+                return default_mtd_writev(mtd, vecs, count, to, retlen);
+        return mtd->writev(mtd, vecs, count, to, retlen);
+}
+EXPORT_SYMBOL_GPL(mtd_writev);
 
 /**
  * mtd_kmalloc_up_to - allocate a contiguous buffer up to the specified size