UBI: do not use vmalloc on I/O path

Similar reason as in case of the previous patch: it causes
deadlocks if a filesystem with writeback support works on top
of UBI. So pre-allocate needed buffers when attaching MTD device.
We also need mutexes to protect the buffers, but they do not
cause much contantion because they are used in recovery, torture,
and WL copy routines, which are called seldom.

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

1 files changed, 22 insertions, 8 deletions

diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 329663188772..cc010111264f 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -274,6 +274,12 @@ struct ubi_wl_entry;
  * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
  * not
  * @mtd: MTD device descriptor
+ *
+ * @peb_buf1: a buffer of PEB size used for different purposes
+ * @peb_buf2: another buffer of PEB size used for different purposes
+ * @buf_mutex: proptects @peb_buf1 and @peb_buf2
+ * @dbg_peb_buf:  buffer of PEB size used for debugging
+ * @dbg_buf_mutex: proptects @dbg_peb_buf
  */
 struct ubi_device {
         struct cdev cdev;
@@ -343,6 +349,14 @@ struct ubi_device {
         int vid_hdr_shift;
         int bad_allowed;
         struct mtd_info *mtd;
+
+        void *peb_buf1;
+        void *peb_buf2;
+        struct mutex buf_mutex;
+#ifdef CONFIG_MTD_UBI_DEBUG
+        void *dbg_peb_buf;
+        struct mutex dbg_buf_mutex;
+#endif
 };
 
 extern struct file_operations ubi_cdev_operations;
@@ -409,18 +423,18 @@ void ubi_wl_close(struct ubi_device *ubi);
 /* io.c */
 int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
                 int len);
-int ubi_io_write(const struct ubi_device *ubi, const void *buf, int pnum,
-                 int offset, int len);
-int ubi_io_sync_erase(const struct ubi_device *ubi, int pnum, int torture);
+int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
+                 int len);
+int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
 int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
 int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
-int ubi_io_read_ec_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
                        struct ubi_ec_hdr *ec_hdr, int verbose);
-int ubi_io_write_ec_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
                         struct ubi_ec_hdr *ec_hdr);
-int ubi_io_read_vid_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
                         struct ubi_vid_hdr *vid_hdr, int verbose);
-int ubi_io_write_vid_hdr(const struct ubi_device *ubi, int pnum,
+int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
                          struct ubi_vid_hdr *vid_hdr);
 
 /*
@@ -494,7 +508,7 @@ static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
  * the beginning of the logical eraseblock, not to the beginning of the
  * physical eraseblock.
  */
-static inline int ubi_io_write_data(const struct ubi_device *ubi, const void *buf,
+static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
                                     int pnum, int offset, int len)
 {
         ubi_assert(offset >= 0);