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, 29 insertions, 37 deletions

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index ba5bc4a5379..52476d884c4 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -98,8 +98,8 @@ static int paranoid_check_ec_hdr(const struct ubi_device *ubi, int pnum,
 static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum);
 static int paranoid_check_vid_hdr(const struct ubi_device *ubi, int pnum,
 				  const struct ubi_vid_hdr *vid_hdr);
-static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
-				 int offset, int len);
+static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
+				 int len);
 #else
 #define paranoid_check_not_bad(ubi, pnum) 0
 #define paranoid_check_peb_ec_hdr(ubi, pnum)  0
@@ -202,8 +202,8 @@ retry:
  * Note, in case of an error, it is possible that something was still written
  * to the flash media, but may be some garbage.
  */
-int ubi_io_write(const struct ubi_device *ubi, const void *buf, int pnum,
-		 int offset, int len)
+int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
+		 int len)
 {
 	int err;
 	size_t written;
@@ -285,7 +285,7 @@ static void erase_callback(struct erase_info *ei)
  * zero in case of success and a negative error code in case of failure. If
  * %-EIO is returned, the physical eraseblock most probably went bad.
  */
-static int do_sync_erase(const struct ubi_device *ubi, int pnum)
+static int do_sync_erase(struct ubi_device *ubi, int pnum)
 {
 	int err, retries = 0;
 	struct erase_info ei;
@@ -377,29 +377,25 @@ static uint8_t patterns[] = {0xa5, 0x5a, 0x0};
  * test, a positive number of erase operations done if the test was
  * successfully passed, and other negative error codes in case of other errors.
  */
-static int torture_peb(const struct ubi_device *ubi, int pnum)
+static int torture_peb(struct ubi_device *ubi, int pnum)
 {
-	void *buf;
 	int err, i, patt_count;
 
-	buf = vmalloc(ubi->peb_size);
-	if (!buf)
-		return -ENOMEM;
-
 	patt_count = ARRAY_SIZE(patterns);
 	ubi_assert(patt_count > 0);
 
+	mutex_lock(&ubi->buf_mutex);
 	for (i = 0; i < patt_count; i++) {
 		err = do_sync_erase(ubi, pnum);
 		if (err)
 			goto out;
 
 		/* Make sure the PEB contains only 0xFF bytes */
-		err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
+		err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 		if (err)
 			goto out;
 
-		err = check_pattern(buf, 0xFF, ubi->peb_size);
+		err = check_pattern(ubi->peb_buf1, 0xFF, ubi->peb_size);
 		if (err == 0) {
 			ubi_err("erased PEB %d, but a non-0xFF byte found",
 				pnum);
@@ -408,17 +404,17 @@ static int torture_peb(const struct ubi_device *ubi, int pnum)
 		}
 
 		/* Write a pattern and check it */
-		memset(buf, patterns[i], ubi->peb_size);
-		err = ubi_io_write(ubi, buf, pnum, 0, ubi->peb_size);
+		memset(ubi->peb_buf1, patterns[i], ubi->peb_size);
+		err = ubi_io_write(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 		if (err)
 			goto out;
 
-		memset(buf, ~patterns[i], ubi->peb_size);
-		err = ubi_io_read(ubi, buf, pnum, 0, ubi->peb_size);
+		memset(ubi->peb_buf1, ~patterns[i], ubi->peb_size);
+		err = ubi_io_read(ubi, ubi->peb_buf1, pnum, 0, ubi->peb_size);
 		if (err)
 			goto out;
 
-		err = check_pattern(buf, patterns[i], ubi->peb_size);
+		err = check_pattern(ubi->peb_buf1, patterns[i], ubi->peb_size);
 		if (err == 0) {
 			ubi_err("pattern %x checking failed for PEB %d",
 				patterns[i], pnum);
@@ -430,6 +426,7 @@ static int torture_peb(const struct ubi_device *ubi, int pnum)
 	err = patt_count;
 
 out:
+	mutex_unlock(&ubi->buf_mutex);
 	if (err == UBI_IO_BITFLIPS || err == -EBADMSG) {
 		/*
 		 * If a bit-flip or data integrity error was detected, the test
@@ -440,7 +437,6 @@ out:
 			pnum);
 		err = -EIO;
 	}
-	vfree(buf);
 	return err;
 }
 
@@ -460,7 +456,7 @@ out:
  * codes in case of other errors. Note, %-EIO means that the physical
  * eraseblock is bad.
  */
-int ubi_io_sync_erase(const struct ubi_device *ubi, int pnum, int torture)
+int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture)
 {
 	int err, ret = 0;
 
@@ -617,7 +613,7 @@ bad:
  * o %UBI_IO_PEB_EMPTY if the physical eraseblock is empty;
  * o a negative error code in case of failure.
  */
-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 err, read_err = 0;
@@ -723,7 +719,7 @@ int ubi_io_read_ec_hdr(const struct ubi_device *ubi, int pnum,
  * case of failure. If %-EIO is returned, the physical eraseblock most probably
  * went bad.
  */
-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 err;
@@ -889,7 +885,7 @@ bad:
  *   header there);
  * o a negative error code in case of failure.
  */
-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 err, read_err = 0;
@@ -996,7 +992,7 @@ int ubi_io_read_vid_hdr(const struct ubi_device *ubi, int pnum,
  * case of failure. If %-EIO is returned, the physical eraseblock probably went
  * bad.
  */
-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)
 {
 	int err;
@@ -1219,44 +1215,40 @@ exit:
  * @offset of the physical eraseblock @pnum, %1 if not, and a negative error
  * code if an error occurred.
  */
-static int paranoid_check_all_ff(const struct ubi_device *ubi, int pnum,
-				 int offset, int len)
+static int paranoid_check_all_ff(struct ubi_device *ubi, int pnum, int offset,
+				 int len)
 {
 	size_t read;
 	int err;
-	void *buf;
 	loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
 
-	buf = vmalloc(len);
-	if (!buf)
-		return -ENOMEM;
-	memset(buf, 0, len);
-
-	err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
+	mutex_lock(&ubi->dbg_buf_mutex);
+	err = ubi->mtd->read(ubi->mtd, addr, len, &read, ubi->dbg_peb_buf);
 	if (err && err != -EUCLEAN) {
 		ubi_err("error %d while reading %d bytes from PEB %d:%d, "
 			"read %zd bytes", err, len, pnum, offset, read);
 		goto error;
 	}
 
-	err = check_pattern(buf, 0xFF, len);
+	err = check_pattern(ubi->dbg_peb_buf, 0xFF, len);
 	if (err == 0) {
 		ubi_err("flash region at PEB %d:%d, length %d does not "
 			"contain all 0xFF bytes", pnum, offset, len);
 		goto fail;
 	}
+	mutex_unlock(&ubi->dbg_buf_mutex);
 
-	vfree(buf);
 	return 0;
 
 fail:
 	ubi_err("paranoid check failed for PEB %d", pnum);
 	dbg_msg("hex dump of the %d-%d region", offset, offset + len);
-	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4,
+		       ubi->dbg_peb_buf, len, 1);
 	err = 1;
 error:
 	ubi_dbg_dump_stack();
-	vfree(buf);
+	mutex_unlock(&ubi->dbg_buf_mutex);
 	return err;
 }