f2fs: clean up error handing of f2fs_submit_page_read()

Below two functions should never fail, clean up error handling in their
callers:
1) f2fs_grab_read_bio() in f2fs_submit_page_read()
2) bio_add_folio() in f2fs_submit_page_read()

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: chaseyu

fs/f2fs/data.c

@@ -1085,7 +1085,7 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 }
 
 /* This can handle encryption stuffs */
-static int f2fs_submit_page_read(struct inode *inode, struct folio *folio,
+static void f2fs_submit_page_read(struct inode *inode, struct folio *folio,
 				 block_t blkaddr, blk_opf_t op_flags,
 				 bool for_write)
 {
@@ -1094,23 +1094,16 @@ static int f2fs_submit_page_read(struct inode *inode, struct folio *folio,
 
 	bio = f2fs_grab_read_bio(inode, blkaddr, 1, op_flags,
 					folio->index, for_write);
-	if (IS_ERR(bio))
-		return PTR_ERR(bio);
 
 	/* wait for GCed page writeback via META_MAPPING */
 	f2fs_wait_on_block_writeback(inode, blkaddr);
 
-	if (!bio_add_folio(bio, folio, PAGE_SIZE, 0)) {
-		iostat_update_and_unbind_ctx(bio);
-		if (bio->bi_private)
-			mempool_free(bio->bi_private, bio_post_read_ctx_pool);
-		bio_put(bio);
-		return -EFAULT;
-	}
+	if (!bio_add_folio(bio, folio, PAGE_SIZE, 0))
+		f2fs_bug_on(sbi, 1);
+
 	inc_page_count(sbi, F2FS_RD_DATA);
 	f2fs_update_iostat(sbi, NULL, FS_DATA_READ_IO, F2FS_BLKSIZE);
 	f2fs_submit_read_bio(sbi, bio, DATA);
-	return 0;
 }
 
 static void __set_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr)
@@ -1267,10 +1260,8 @@ struct folio *f2fs_get_read_data_folio(struct inode *inode, pgoff_t index,
 		return folio;
 	}
 
-	err = f2fs_submit_page_read(inode, folio, dn.data_blkaddr,
+	f2fs_submit_page_read(inode, folio, dn.data_blkaddr,
 						op_flags, for_write);
-	if (err)
-		goto put_err;
 	return folio;
 
 put_err:
@@ -2147,16 +2138,10 @@ static int f2fs_read_single_page(struct inode *inode, struct folio *folio,
 		f2fs_submit_read_bio(F2FS_I_SB(inode), bio, DATA);
 		bio = NULL;
 	}
-	if (bio == NULL) {
+	if (bio == NULL)
 		bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
 				f2fs_ra_op_flags(rac), index,
 				false);
-		if (IS_ERR(bio)) {
-			ret = PTR_ERR(bio);
-			bio = NULL;
-			goto out;
-		}
-	}
 
 	/*
 	 * If the page is under writeback, we need to wait for
@@ -2305,18 +2290,10 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
 			bio = NULL;
 		}
 
-		if (!bio) {
+		if (!bio)
 			bio = f2fs_grab_read_bio(inode, blkaddr, nr_pages - i,
 					f2fs_ra_op_flags(rac),
 					folio->index, for_write);
-			if (IS_ERR(bio)) {
-				ret = PTR_ERR(bio);
-				f2fs_decompress_end_io(dic, ret, true);
-				f2fs_put_dnode(&dn);
-				*bio_ret = NULL;
-				return ret;
-			}
-		}
 
 		if (!bio_add_folio(bio, folio, blocksize, 0))
 			goto submit_and_realloc;
@@ -3641,11 +3618,9 @@ static int f2fs_write_begin(const struct kiocb *iocb,
 			err = -EFSCORRUPTED;
 			goto put_folio;
 		}
-		err = f2fs_submit_page_read(use_cow ?
+		f2fs_submit_page_read(use_cow ?
 				F2FS_I(inode)->cow_inode : inode,
 				folio, blkaddr, 0, true);
-		if (err)
-			goto put_folio;
 
 		folio_lock(folio);
 		if (unlikely(folio->mapping != mapping)) {