UBI: reduce memory consumption
Remove the pre-allocated 'peb_buf2' buffer because we do not really need it.
The only reason UBI has it is to check that the data were written correctly.
But we do not have to have 2 buffers for this and waste RAM - we can just
compare CRC checksums instead. This reduces UBI memory consumption.
Artem bityutskiy: massaged the patch and commit message
Signed-off-by: Josselin Costanzi <josselin.costanzi@mobile-devices.fr>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 115749f..6e0806b 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -949,10 +949,6 @@
if (!ubi->peb_buf1)
goto out_free;
- ubi->peb_buf2 = vmalloc(ubi->peb_size);
- if (!ubi->peb_buf2)
- goto out_free;
-
err = ubi_debugging_init_dev(ubi);
if (err)
goto out_free;
@@ -1030,7 +1026,6 @@
ubi_debugging_exit_dev(ubi);
out_free:
vfree(ubi->peb_buf1);
- vfree(ubi->peb_buf2);
if (ref)
put_device(&ubi->dev);
else
@@ -1102,7 +1097,6 @@
put_mtd_device(ubi->mtd);
ubi_debugging_exit_dev(ubi);
vfree(ubi->peb_buf1);
- vfree(ubi->peb_buf2);
ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
put_device(&ubi->dev);
return 0;
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index cd26da8..f548af3 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -1134,8 +1134,8 @@
* We've written the data and are going to read it back to make
* sure it was written correctly.
*/
-
- err = ubi_io_read_data(ubi, ubi->peb_buf2, to, 0, aldata_size);
+ memset(ubi->peb_buf1, 0xFF, aldata_size);
+ err = ubi_io_read_data(ubi, ubi->peb_buf1, to, 0, aldata_size);
if (err) {
if (err != UBI_IO_BITFLIPS) {
ubi_warn("error %d while reading data back "
@@ -1149,7 +1149,7 @@
cond_resched();
- if (memcmp(ubi->peb_buf1, ubi->peb_buf2, aldata_size)) {
+ if (crc != crc32(UBI_CRC32_INIT, ubi->peb_buf1, data_size)) {
ubi_warn("read data back from PEB %d and it is "
"different", to);
err = -EINVAL;
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index d51d75d..cb93ad9 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -388,8 +388,7 @@
* @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: protects @peb_buf1 and @peb_buf2
+ * @buf_mutex: protects @peb_buf1
* @ckvol_mutex: serializes static volume checking when opening
*
* @dbg: debugging information for this UBI device
@@ -472,7 +471,6 @@
struct mtd_info *mtd;
void *peb_buf1;
- void *peb_buf2;
struct mutex buf_mutex;
struct mutex ckvol_mutex;