UBI: do not allocate the memory unnecessarily

dedekind · dedekind · commit d125a753425b · 2012-10-26T16:29:46.000+03:00
UBI reserves an LEB sized buffer for various needs. We can use this buffer
while scanning, instead of allocating another one. This patch was originally
created by Jan Luebbe &lt;jlu@pengutronix.de&gt;, but then he dropped it and I picked
up and tweaked a little bit.

Signed-off-by: Artem Bityutskiy &lt;artem.bityutskiy@linux.intel.com&gt;
diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
@@ -322,7 +322,6 @@ static struct ubi_ainf_volume *add_volume(struct ubi_attach_info *ai,
 int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
 			int pnum, const struct ubi_vid_hdr *vid_hdr)
 {
-	void *buf;
 	int len, err, second_is_newer, bitflips = 0, corrupted = 0;
 	uint32_t data_crc, crc;
 	struct ubi_vid_hdr *vh = NULL;
@@ -393,18 +392,14 @@ int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
 	/* Read the data of the copy and check the CRC */
 
 	len = be32_to_cpu(vid_hdr->data_size);
-	buf = vmalloc(len);
-	if (!buf) {
-		err = -ENOMEM;
-		goto out_free_vidh;
-	}
 
-	err = ubi_io_read_data(ubi, buf, pnum, 0, len);
+	mutex_lock(&ubi->buf_mutex);
+	err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, len);
 	if (err && err != UBI_IO_BITFLIPS && !mtd_is_eccerr(err))
-		goto out_free_buf;
+		goto out_unlock;
 
 	data_crc = be32_to_cpu(vid_hdr->data_crc);
-	crc = crc32(UBI_CRC32_INIT, buf, len);
+	crc = crc32(UBI_CRC32_INIT, ubi->peb_buf, len);
 	if (crc != data_crc) {
 		dbg_bld("PEB %d CRC error: calculated %#08x, must be %#08x",
 			pnum, crc, data_crc);
@@ -415,8 +410,8 @@ int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
 		dbg_bld("PEB %d CRC is OK", pnum);
 		bitflips = !!err;
 	}
+	mutex_unlock(&ubi->buf_mutex);
 
-	vfree(buf);
 	ubi_free_vid_hdr(ubi, vh);
 
 	if (second_is_newer)
@@ -426,8 +421,8 @@ int ubi_compare_lebs(struct ubi_device *ubi, const struct ubi_ainf_peb *aeb,
 
 	return second_is_newer | (bitflips << 1) | (corrupted << 2);
 
-out_free_buf:
-	vfree(buf);
+out_unlock:
+	mutex_unlock(&ubi->buf_mutex);
 out_free_vidh:
 	ubi_free_vid_hdr(ubi, vh);
 	return err;
