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bf2870c1d9
This bug applied where mtd partition end address, or erase start address, was not cleanly divisible by parent mtd erasesize. This error would cause the bits following the end of the partition to the next erasesize block boundary to be erased, and this partition-overflow data to be written to the partition erase address (missing additional partition offset address) of the mtd (top) parent device. Fixes: FS#2428 Signed-off-by: John Thomson <git@johnthomson.fastmail.com.au> Tested-by: Tomasz Maciej Nowak <tomek_n@o2.pl> [shorten commit title, add Fixes, fix kernel 4.19 as well] Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
131 lines
3.8 KiB
Diff
131 lines
3.8 KiB
Diff
From: Felix Fietkau <nbd@nbd.name>
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Subject: mtd: implement write support for partitions covering only a part of an eraseblock (buffer data that would otherwise be erased)
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lede-commit: 87a8e8ac1067f58ba831c4aae443f3655c31cd80
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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drivers/mtd/mtdpart.c | 90 ++++++++++++++++++++++++++++++++++++++++++++-----
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include/linux/mtd/mtd.h | 4 +++
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2 files changed, 85 insertions(+), 9 deletions(-)
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--- a/drivers/mtd/mtdpart.c
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+++ b/drivers/mtd/mtdpart.c
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@@ -22,6 +22,8 @@
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#include "mtdcore.h"
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#include "mtdsplit/mtdsplit.h"
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+#define MTD_ERASE_PARTIAL 0x8000 /* partition only covers parts of an erase block */
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+
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/* Our partition linked list */
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static LIST_HEAD(mtd_partitions);
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static DEFINE_MUTEX(mtd_partitions_mutex);
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@@ -206,11 +208,77 @@ static int part_erase(struct mtd_info *m
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{
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struct mtd_part *part = mtd_to_part(mtd);
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int ret;
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+ size_t wrlen = 0;
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+ u8 *erase_buf = NULL;
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+ u32 erase_buf_ofs = 0;
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+ bool partial_start = false;
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+
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+ if (mtd->flags & MTD_ERASE_PARTIAL) {
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+ size_t readlen = 0;
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+ u64 mtd_ofs;
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+
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+ erase_buf = kmalloc(part->parent->erasesize, GFP_ATOMIC);
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+ if (!erase_buf)
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+ return -ENOMEM;
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+
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+ mtd_ofs = part->offset + instr->addr;
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+ erase_buf_ofs = do_div(mtd_ofs, part->parent->erasesize);
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+
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+ if (erase_buf_ofs > 0) {
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+ instr->addr -= erase_buf_ofs;
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+ ret = mtd_read(part->parent,
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+ instr->addr + part->offset,
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+ part->parent->erasesize,
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+ &readlen, erase_buf);
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+
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+ instr->len += erase_buf_ofs;
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+ partial_start = true;
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+ } else {
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+ mtd_ofs = part->offset + part->mtd.size;
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+ erase_buf_ofs = part->parent->erasesize -
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+ do_div(mtd_ofs, part->parent->erasesize);
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+
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+ if (erase_buf_ofs > 0) {
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+ instr->len += erase_buf_ofs;
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+ ret = mtd_read(part->parent,
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+ part->offset + instr->addr +
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+ instr->len - part->parent->erasesize,
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+ part->parent->erasesize, &readlen,
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+ erase_buf);
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+ } else {
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+ ret = 0;
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+ }
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+ }
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+ if (ret < 0) {
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+ kfree(erase_buf);
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+ return ret;
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+ }
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+
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+ }
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instr->addr += part->offset;
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ret = part->parent->_erase(part->parent, instr);
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if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
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instr->fail_addr -= part->offset;
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+
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+ if (mtd->flags & MTD_ERASE_PARTIAL) {
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+ if (partial_start) {
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+ part->parent->_write(part->parent,
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+ instr->addr, erase_buf_ofs,
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+ &wrlen, erase_buf);
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+ instr->addr += erase_buf_ofs;
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+ } else {
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+ instr->len -= erase_buf_ofs;
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+ part->parent->_write(part->parent,
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+ instr->addr + instr->len,
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+ erase_buf_ofs, &wrlen,
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+ erase_buf +
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+ part->parent->erasesize -
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+ erase_buf_ofs);
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+ }
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+ kfree(erase_buf);
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+ }
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+
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instr->addr -= part->offset;
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return ret;
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@@ -525,19 +593,22 @@ static struct mtd_part *allocate_partiti
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remainder = do_div(tmp, wr_alignment);
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if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
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/* Doesn't start on a boundary of major erase size */
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- /* FIXME: Let it be writable if it is on a boundary of
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- * _minor_ erase size though */
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- slave->mtd.flags &= ~MTD_WRITEABLE;
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- printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
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- part->name);
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+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
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+ if (((u32)slave->mtd.size) > parent->erasesize)
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+ slave->mtd.flags &= ~MTD_WRITEABLE;
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+ else
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+ slave->mtd.erasesize = slave->mtd.size;
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}
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tmp = part_absolute_offset(parent) + slave->offset + slave->mtd.size;
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remainder = do_div(tmp, wr_alignment);
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if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
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- slave->mtd.flags &= ~MTD_WRITEABLE;
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- printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
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- part->name);
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+ slave->mtd.flags |= MTD_ERASE_PARTIAL;
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+
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+ if ((u32)slave->mtd.size > parent->erasesize)
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+ slave->mtd.flags &= ~MTD_WRITEABLE;
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+ else
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+ slave->mtd.erasesize = slave->mtd.size;
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}
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mtd_set_ooblayout(&slave->mtd, &part_ooblayout_ops);
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