diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 6f6e3d0af..526706480 100755
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -125,11 +125,11 @@ static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
 }
 
 static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
-			void *inpage, unsigned int *inputmargin, int *maptype,
-			bool support_0padding)
+		void *inpage, void *out, unsigned int *inputmargin, int *maptype,
+		bool support_0padding)
 {
 	unsigned int nrpages_in, nrpages_out;
-	unsigned int ofull, oend, inputsize, total, i, j;
+	unsigned int ofull, oend, inputsize, total, i;
 	struct page **in;
 	void *src, *tmp;
 
@@ -144,12 +144,13 @@ static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
 		    ofull - oend < LZ4_DECOMPRESS_INPLACE_MARGIN(inputsize))
 			goto docopy;
 
-		for (i = 0; i < nrpages_in; ++i) {
-			DBG_BUGON(rq->in[i] == NULL);
-			for (j = 0; j < nrpages_out - nrpages_in + i; ++j)
-				if (rq->out[j] == rq->in[i])
-					goto docopy;
-		}
+		for (i = 0; i < nrpages_in; ++i)
+			if (rq->out[nrpages_out - nrpages_in + i] !=
+			    rq->in[i])
+				goto docopy;
+		kunmap_atomic(inpage);
+		*maptype = 3;
+		return out + ((nrpages_out - nrpages_in) << PAGE_SHIFT);
 	}
 
 	if (nrpages_in <= 1) {
@@ -157,7 +158,6 @@ static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
 		return inpage;
 	}
 	kunmap_atomic(inpage);
-	might_sleep();
 	src = erofs_vm_map_ram(rq->in, nrpages_in);
 	if (!src)
 		return ERR_PTR(-ENOMEM);
@@ -194,10 +194,10 @@ docopy:
 	return src;
 }
 
-static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
+static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *dst)
 {
 	unsigned int inputmargin;
-	u8 *headpage, *src;
+	u8 *out, *headpage, *src;
 	bool support_0padding;
 	int ret, maptype;
 
@@ -221,11 +221,12 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 	}
 
 	rq->inputsize -= inputmargin;
-	src = z_erofs_handle_inplace_io(rq, headpage, &inputmargin, &maptype,
-					support_0padding);
+	src = z_erofs_handle_inplace_io(rq, headpage, dst, &inputmargin,
+					&maptype, support_0padding);
 	if (IS_ERR(src))
 		return PTR_ERR(src);
 
+	out = dst + rq->pageofs_out;
 	/* legacy format could compress extra data in a pcluster. */
 	if (rq->partial_decoding || !support_0padding)
 		ret = LZ4_decompress_safe_partial(src + inputmargin, out,
@@ -254,7 +255,7 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 		vm_unmap_ram(src, PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT);
 	} else if (maptype == 2) {
 		erofs_put_pcpubuf(src);
-	} else {
+	} else if (maptype != 3) {
 		DBG_BUGON(1);
 		return -EFAULT;
 	}
@@ -355,8 +356,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 	dst_maptype = 2;
 
 dstmap_out:
-	ret = alg->decompress(rq, dst + rq->pageofs_out);
-
+	ret = alg->decompress(rq, dst);
 	if (!dst_maptype)
 		kunmap_atomic(dst);
 	else if (dst_maptype == 2)