// SPDX-License-Identifier: GPL-2.0/* *  linux/fs/hpfs/buffer.c * *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999 * *  general buffer i/o */#include <linux/sched.h>#include <linux/slab.h>#include <linux/blkdev.h>#include "hpfs_fn.h" secno hpfs_search_hotfix_map(struct super_block *s, secno sec){	unsigned i;	struct hpfs_sb_info *sbi = hpfs_sb(s);	for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {		if (sbi->hotfix_from[i] == sec) {			return sbi->hotfix_to[i];		}	}	return sec;} unsigned hpfs_search_hotfix_map_for_range(struct super_block *s, secno sec, unsigned n){	unsigned i;	struct hpfs_sb_info *sbi = hpfs_sb(s);	for (i = 0; unlikely(i < sbi->n_hotfixes); i++) {		if (sbi->hotfix_from[i] >= sec && sbi->hotfix_from[i] < sec + n) {			n = sbi->hotfix_from[i] - sec;		}	}	return n;} void hpfs_prefetch_sectors(struct super_block *s, unsigned secno, int n){	struct buffer_head *bh;	struct blk_plug plug; 	if (n <= 0 || unlikely(secno >= hpfs_sb(s)->sb_fs_size))		return; 	if (unlikely(hpfs_search_hotfix_map_for_range(s, secno, n) != n))		return; 	bh = sb_find_get_block(s, secno);	if (bh) {		if (buffer_uptodate(bh)) {			brelse(bh);			return;		}		brelse(bh);	} 	blk_start_plug(&plug);	while (n > 0) {		if (unlikely(secno >= hpfs_sb(s)->sb_fs_size))			break;		sb_breadahead(s, secno);		secno++;		n--;	}	blk_finish_plug(&plug);} /* Map a sector into a buffer and return pointers to it and to the buffer. */ void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp,		 int ahead){	struct buffer_head *bh; 	hpfs_lock_assert(s); 	hpfs_prefetch_sectors(s, secno, ahead); 	cond_resched(); 	*bhp = bh = sb_bread(s, hpfs_search_hotfix_map(s, secno));	if (bh != NULL)		return bh->b_data;	else {		pr_err("%s(): read error\n", __func__);		return NULL;	}} /* Like hpfs_map_sector but don't read anything */ void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp){	struct buffer_head *bh;	/*return hpfs_map_sector(s, secno, bhp, 0);*/ 	hpfs_lock_assert(s); 	cond_resched(); 	if ((*bhp = bh = sb_getblk(s, hpfs_search_hotfix_map(s, secno))) != NULL) {		if (!buffer_uptodate(bh)) wait_on_buffer(bh);		set_buffer_uptodate(bh);		return bh->b_data;	} else {		pr_err("%s(): getblk failed\n", __func__);		return NULL;	}} /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */ void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffer_head *qbh,		   int ahead){	char *data; 	hpfs_lock_assert(s); 	cond_resched(); 	if (secno & 3) {		pr_err("%s(): unaligned read\n", __func__);		return NULL;	} 	hpfs_prefetch_sectors(s, secno, 4 + ahead); 	if (!hpfs_map_sector(s, secno + 0, &qbh->bh[0], 0)) goto bail0;	if (!hpfs_map_sector(s, secno + 1, &qbh->bh[1], 0)) goto bail1;	if (!hpfs_map_sector(s, secno + 2, &qbh->bh[2], 0)) goto bail2;	if (!hpfs_map_sector(s, secno + 3, &qbh->bh[3], 0)) goto bail3; 	if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&	    likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&	    likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {		return qbh->data = qbh->bh[0]->b_data;	} 	qbh->data = data = kmalloc(2048, GFP_NOFS);	if (!data) {		pr_err("%s(): out of memory\n", __func__);		goto bail4;	} 	memcpy(data + 0 * 512, qbh->bh[0]->b_data, 512);	memcpy(data + 1 * 512, qbh->bh[1]->b_data, 512);	memcpy(data + 2 * 512, qbh->bh[2]->b_data, 512);	memcpy(data + 3 * 512, qbh->bh[3]->b_data, 512); 	return data;  bail4:	brelse(qbh->bh[3]); bail3:	brelse(qbh->bh[2]); bail2:	brelse(qbh->bh[1]); bail1:	brelse(qbh->bh[0]); bail0:	return NULL;} /* Don't read sectors */ void *hpfs_get_4sectors(struct super_block *s, unsigned secno,                          struct quad_buffer_head *qbh){	cond_resched(); 	hpfs_lock_assert(s); 	if (secno & 3) {		pr_err("%s(): unaligned read\n", __func__);		return NULL;	} 	if (!hpfs_get_sector(s, secno + 0, &qbh->bh[0])) goto bail0;	if (!hpfs_get_sector(s, secno + 1, &qbh->bh[1])) goto bail1;	if (!hpfs_get_sector(s, secno + 2, &qbh->bh[2])) goto bail2;	if (!hpfs_get_sector(s, secno + 3, &qbh->bh[3])) goto bail3; 	if (likely(qbh->bh[1]->b_data == qbh->bh[0]->b_data + 1 * 512) &&	    likely(qbh->bh[2]->b_data == qbh->bh[0]->b_data + 2 * 512) &&	    likely(qbh->bh[3]->b_data == qbh->bh[0]->b_data + 3 * 512)) {		return qbh->data = qbh->bh[0]->b_data;	} 	if (!(qbh->data = kmalloc(2048, GFP_NOFS))) {		pr_err("%s(): out of memory\n", __func__);		goto bail4;	}	return qbh->data; bail4:	brelse(qbh->bh[3]);bail3:	brelse(qbh->bh[2]);bail2:	brelse(qbh->bh[1]);bail1:	brelse(qbh->bh[0]);bail0:	return NULL;}	 void hpfs_brelse4(struct quad_buffer_head *qbh){	if (unlikely(qbh->data != qbh->bh[0]->b_data))		kfree(qbh->data);	brelse(qbh->bh[0]);	brelse(qbh->bh[1]);	brelse(qbh->bh[2]);	brelse(qbh->bh[3]);}	 void hpfs_mark_4buffers_dirty(struct quad_buffer_head *qbh){	if (unlikely(qbh->data != qbh->bh[0]->b_data)) {		memcpy(qbh->bh[0]->b_data, qbh->data + 0 * 512, 512);		memcpy(qbh->bh[1]->b_data, qbh->data + 1 * 512, 512);		memcpy(qbh->bh[2]->b_data, qbh->data + 2 * 512, 512);		memcpy(qbh->bh[3]->b_data, qbh->data + 3 * 512, 512);	}	mark_buffer_dirty(qbh->bh[0]);	mark_buffer_dirty(qbh->bh[1]);	mark_buffer_dirty(qbh->bh[2]);	mark_buffer_dirty(qbh->bh[3]);}