add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/mtd/mtdblock.c
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@@ -1,23 +1,9 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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  * Direct MTD block device access
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  *
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  * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org>
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  * Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net>
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2 of the License, or
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- * (at your option) any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program; if not, write to the Free Software
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- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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- *
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  */
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8
 
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 #include <linux/fs.h>
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@@ -56,7 +42,7 @@
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  */
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 static int erase_write (struct mtd_info *mtd, unsigned long pos,
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-			int len, const char *buf)
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+			unsigned int len, const char *buf)
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 {
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 	struct erase_info erase;
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 	size_t retlen;
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@@ -103,8 +89,6 @@
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 	ret = erase_write (mtd, mtdblk->cache_offset,
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 			   mtdblk->cache_size, mtdblk->cache_data);
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-	if (ret)
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-		return ret;
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 	/*
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 	 * Here we could arguably set the cache state to STATE_CLEAN.
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@@ -112,9 +96,14 @@
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 	 * be notified if this content is altered on the flash by other
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 	 * means.  Let's declare it empty and leave buffering tasks to
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 	 * the buffer cache instead.
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+	 *
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+	 * If this cache_offset points to a bad block, data cannot be
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+	 * written to the device. Clear cache_state to avoid writing to
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+	 * bad blocks repeatedly.
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 	 */
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-	mtdblk->cache_state = STATE_EMPTY;
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-	return 0;
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+	if (ret == 0 || ret == -EIO)
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+		mtdblk->cache_state = STATE_EMPTY;
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+	return ret;
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 }
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@@ -164,7 +153,7 @@
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 				mtdblk->cache_state = STATE_EMPTY;
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 				ret = mtd_read(mtd, sect_start, sect_size,
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 					       &retlen, mtdblk->cache_data);
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-				if (ret)
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+				if (ret && !mtd_is_bitflip(ret))
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 					return ret;
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 				if (retlen != sect_size)
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 					return -EIO;
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@@ -199,8 +188,12 @@
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 	pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n",
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 			mtd->name, pos, len);
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-	if (!sect_size)
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-		return mtd_read(mtd, pos, len, &retlen, buf);
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+	if (!sect_size) {
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+		ret = mtd_read(mtd, pos, len, &retlen, buf);
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+		if (ret && !mtd_is_bitflip(ret))
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+			return ret;
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+		return 0;
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+	}
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 	while (len > 0) {
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 		unsigned long sect_start = (pos/sect_size)*sect_size;
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@@ -220,7 +213,7 @@
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 			memcpy (buf, mtdblk->cache_data + offset, size);
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 		} else {
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 			ret = mtd_read(mtd, pos, size, &retlen, buf);
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-			if (ret)
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+			if (ret && !mtd_is_bitflip(ret))
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 				return ret;
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 			if (retlen != size)
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 				return -EIO;
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@@ -308,12 +301,13 @@
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 static int mtdblock_flush(struct mtd_blktrans_dev *dev)
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 {
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 	struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd);
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+	int ret;
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 	mutex_lock(&mtdblk->cache_mutex);
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-	write_cached_data(mtdblk);
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+	ret = write_cached_data(mtdblk);
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 	mutex_unlock(&mtdblk->cache_mutex);
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 	mtd_sync(dev->mtd);
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-	return 0;
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+	return ret;
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 }
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 static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)