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OpenCloudOS-Kernel
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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>
This commit is contained in:
Josselin Costanzi 2012-02-22 16:37:05 +01:00 committed by Artem Bityutskiy
parent 7eb3aa6585
commit 43b043e78b
3 changed files with 4 additions and 12 deletions
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6
drivers/mtd/ubi/build.c
View File

@ -949,10 +949,6 @@ int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
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 @@ out_debugging:
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 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
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;

6
drivers/mtd/ubi/eba.c
View File

@ -1134,8 +1134,8 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
* 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 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
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;

4
drivers/mtd/ubi/ubi.h
View File

@ -388,8 +388,7 @@ struct ubi_wl_entry;
* @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 ubi_device {
struct mtd_info *mtd;
void *peb_buf1;
void *peb_buf2;
struct mutex buf_mutex;
struct mutex ckvol_mutex;