erofs: reference struct erofs_device_info for erofs_map_dev

Record `m_sb` and `m_dif` to replace `m_fscache`, `m_daxdev`, `m_fp`
and `m_dax_part_off` in order to simplify the codebase.

Note that `m_bdev` is still left since it can be assigned from
`sb->s_bdev` directly.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20241212235401.2857246-1-hsiangkao@linux.alibaba.com

Author: hsiangkao

fs/erofs/data.c

@@ -179,19 +179,13 @@ int erofs_map_blocks(struct inode *inode, struct erofs_map_blocks *map)
 }
 
 static void erofs_fill_from_devinfo(struct erofs_map_dev *map,
-				    struct erofs_device_info *dif)
+		struct super_block *sb, struct erofs_device_info *dif)
 {
+	map->m_sb = sb;
+	map->m_dif = dif;
 	map->m_bdev = NULL;
-	map->m_fp = NULL;
-	if (dif->file) {
-		if (S_ISBLK(file_inode(dif->file)->i_mode))
-			map->m_bdev = file_bdev(dif->file);
-		else
-			map->m_fp = dif->file;
-	}
-	map->m_daxdev = dif->dax_dev;
-	map->m_dax_part_off = dif->dax_part_off;
-	map->m_fscache = dif->fscache;
+	if (dif->file && S_ISBLK(file_inode(dif->file)->i_mode))
+		map->m_bdev = file_bdev(dif->file);
 }
 
 int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
@@ -201,7 +195,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 	erofs_off_t startoff, length;
 	int id;
 
-	erofs_fill_from_devinfo(map, &EROFS_SB(sb)->dif0);
+	erofs_fill_from_devinfo(map, sb, &EROFS_SB(sb)->dif0);
 	map->m_bdev = sb->s_bdev;	/* use s_bdev for the primary device */
 	if (map->m_deviceid) {
 		down_read(&devs->rwsem);
@@ -215,7 +209,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			up_read(&devs->rwsem);
 			return 0;
 		}
-		erofs_fill_from_devinfo(map, dif);
+		erofs_fill_from_devinfo(map, sb, dif);
 		up_read(&devs->rwsem);
 	} else if (devs->extra_devices && !devs->flatdev) {
 		down_read(&devs->rwsem);
@@ -228,7 +222,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			if (map->m_pa >= startoff &&
 			    map->m_pa < startoff + length) {
 				map->m_pa -= startoff;
-				erofs_fill_from_devinfo(map, dif);
+				erofs_fill_from_devinfo(map, sb, dif);
 				break;
 			}
 		}
@@ -298,7 +292,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 
 	iomap->offset = map.m_la;
 	if (flags & IOMAP_DAX)
-		iomap->dax_dev = mdev.m_daxdev;
+		iomap->dax_dev = mdev.m_dif->dax_dev;
 	else
 		iomap->bdev = mdev.m_bdev;
 	iomap->length = map.m_llen;
@@ -327,7 +321,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 		iomap->type = IOMAP_MAPPED;
 		iomap->addr = mdev.m_pa;
 		if (flags & IOMAP_DAX)
-			iomap->addr += mdev.m_dax_part_off;
+			iomap->addr += mdev.m_dif->dax_part_off;
 	}
 	return 0;
 }

fs/erofs/fileio.c

@@ -67,7 +67,7 @@ static struct erofs_fileio_rq *erofs_fileio_rq_alloc(struct erofs_map_dev *mdev)
 					     GFP_KERNEL | __GFP_NOFAIL);
 
 	bio_init(&rq->bio, NULL, rq->bvecs, BIO_MAX_VECS, REQ_OP_READ);
-	rq->iocb.ki_filp = mdev->m_fp;
+	rq->iocb.ki_filp = mdev->m_dif->file;
 	return rq;
 }
 

fs/erofs/fscache.c

@@ -198,7 +198,7 @@ struct bio *erofs_fscache_bio_alloc(struct erofs_map_dev *mdev)
 
 	io = kmalloc(sizeof(*io), GFP_KERNEL | __GFP_NOFAIL);
 	bio_init(&io->bio, NULL, io->bvecs, BIO_MAX_VECS, REQ_OP_READ);
-	io->io.private = mdev->m_fscache->cookie;
+	io->io.private = mdev->m_dif->fscache->cookie;
 	io->io.end_io = erofs_fscache_bio_endio;
 	refcount_set(&io->io.ref, 1);
 	return &io->bio;
@@ -316,7 +316,7 @@ static int erofs_fscache_data_read_slice(struct erofs_fscache_rq *req)
 	if (!io)
 		return -ENOMEM;
 	iov_iter_xarray(&io->iter, ITER_DEST, &mapping->i_pages, pos, count);
-	ret = erofs_fscache_read_io_async(mdev.m_fscache->cookie,
+	ret = erofs_fscache_read_io_async(mdev.m_dif->fscache->cookie,
 			mdev.m_pa + (pos - map.m_la), io);
 	erofs_fscache_req_io_put(io);
 

fs/erofs/internal.h

@@ -353,11 +353,9 @@ enum {
 };
 
 struct erofs_map_dev {
-	struct erofs_fscache *m_fscache;
+	struct super_block *m_sb;
+	struct erofs_device_info *m_dif;
 	struct block_device *m_bdev;
-	struct dax_device *m_daxdev;
-	struct file *m_fp;
-	u64 m_dax_part_off;
 
 	erofs_off_t m_pa;
 	unsigned int m_deviceid;