Changes since last update:

- Fix two unexpected loop cases when reading beyond EOF;
 
  - Fix fsdax unavailability for chunk-based regular files;
 
  - Get rid of the remaining kmap_atomic();
 
  - Minor cleanups.
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Merge tag 'erofs-for-6.5-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:
 "Three patches address regressions related to post-EOF unexpected
  behaviors and fsdax unavailability of chunk-based regular files.

  The other two patches mainly get rid of kmap_atomic() and simplify
  z_erofs_transform_plain().

   - Fix two unexpected loop cases when reading beyond EOF

   - Fix fsdax unavailability for chunk-based regular files

   - Get rid of the remaining kmap_atomic()

   - Minor cleanups"

* tag 'erofs-for-6.5-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: fix fsdax unavailability for chunk-based regular files
  erofs: avoid infinite loop in z_erofs_do_read_page() when reading beyond EOF
  erofs: avoid useless loops in z_erofs_pcluster_readmore() when reading beyond EOF
  erofs: simplify z_erofs_transform_plain()
  erofs: get rid of the remaining kmap_atomic()

fs/erofs/decompressor.c

@@ -148,7 +148,7 @@ static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
 		*maptype = 0;
 		return inpage;
 	}
-	kunmap_atomic(inpage);
+	kunmap_local(inpage);
 	might_sleep();
 	src = erofs_vm_map_ram(rq->in, ctx->inpages);
 	if (!src)
@@ -162,7 +162,7 @@ docopy:
 	src = erofs_get_pcpubuf(ctx->inpages);
 	if (!src) {
 		DBG_BUGON(1);
-		kunmap_atomic(inpage);
+		kunmap_local(inpage);
 		return ERR_PTR(-EFAULT);
 	}
 
@@ -173,9 +173,9 @@ docopy:
 			min_t(unsigned int, total, PAGE_SIZE - *inputmargin);
 
 		if (!inpage)
-			inpage = kmap_atomic(*in);
+			inpage = kmap_local_page(*in);
 		memcpy(tmp, inpage + *inputmargin, page_copycnt);
-		kunmap_atomic(inpage);
+		kunmap_local(inpage);
 		inpage = NULL;
 		tmp += page_copycnt;
 		total -= page_copycnt;
@@ -214,7 +214,7 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 	int ret, maptype;
 
 	DBG_BUGON(*rq->in == NULL);
-	headpage = kmap_atomic(*rq->in);
+	headpage = kmap_local_page(*rq->in);
 
 	/* LZ4 decompression inplace is only safe if zero_padding is enabled */
 	if (erofs_sb_has_zero_padding(EROFS_SB(rq->sb))) {
@@ -223,7 +223,7 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 				min_t(unsigned int, rq->inputsize,
 				      rq->sb->s_blocksize - rq->pageofs_in));
 		if (ret) {
-			kunmap_atomic(headpage);
+			kunmap_local(headpage);
 			return ret;
 		}
 		may_inplace = !((rq->pageofs_in + rq->inputsize) &
@@ -261,7 +261,7 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
 	}
 
 	if (maptype == 0) {
-		kunmap_atomic(headpage);
+		kunmap_local(headpage);
 	} else if (maptype == 1) {
 		vm_unmap_ram(src, ctx->inpages);
 	} else if (maptype == 2) {
@@ -289,7 +289,7 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
 	/* one optimized fast path only for non bigpcluster cases yet */
 	if (ctx.inpages == 1 && ctx.outpages == 1 && !rq->inplace_io) {
 		DBG_BUGON(!*rq->out);
-		dst = kmap_atomic(*rq->out);
+		dst = kmap_local_page(*rq->out);
 		dst_maptype = 0;
 		goto dstmap_out;
 	}
@@ -311,7 +311,7 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
 dstmap_out:
 	ret = z_erofs_lz4_decompress_mem(&ctx, dst + rq->pageofs_out);
 	if (!dst_maptype)
-		kunmap_atomic(dst);
+		kunmap_local(dst);
 	else if (dst_maptype == 2)
 		vm_unmap_ram(dst, ctx.outpages);
 	return ret;
@@ -328,7 +328,7 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
 	const unsigned int lefthalf = rq->outputsize - righthalf;
 	const unsigned int interlaced_offset =
 		rq->alg == Z_EROFS_COMPRESSION_SHIFTED ? 0 : rq->pageofs_out;
-	unsigned char *src, *dst;
+	u8 *src;
 
 	if (outpages > 2 && rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
 		DBG_BUGON(1);
@@ -341,22 +341,19 @@ static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
 	}
 
 	src = kmap_local_page(rq->in[inpages - 1]) + rq->pageofs_in;
-	if (rq->out[0]) {
-		dst = kmap_local_page(rq->out[0]);
-		memcpy(dst + rq->pageofs_out, src + interlaced_offset,
-		       righthalf);
-		kunmap_local(dst);
-	}
+	if (rq->out[0])
+		memcpy_to_page(rq->out[0], rq->pageofs_out,
+			       src + interlaced_offset, righthalf);
 
 	if (outpages > inpages) {
 		DBG_BUGON(!rq->out[outpages - 1]);
 		if (rq->out[outpages - 1] != rq->in[inpages - 1]) {
-			dst = kmap_local_page(rq->out[outpages - 1]);
-			memcpy(dst, interlaced_offset ? src :
-					(src + righthalf), lefthalf);
-			kunmap_local(dst);
+			memcpy_to_page(rq->out[outpages - 1], 0, src +
+					(interlaced_offset ? 0 : righthalf),
+				       lefthalf);
 		} else if (!interlaced_offset) {
 			memmove(src, src + righthalf, lefthalf);
+			flush_dcache_page(rq->in[inpages - 1]);
 		}
 	}
 	kunmap_local(src);

fs/erofs/inode.c

@@ -183,7 +183,8 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 
 	inode->i_flags &= ~S_DAX;
 	if (test_opt(&sbi->opt, DAX_ALWAYS) && S_ISREG(inode->i_mode) &&
-	    vi->datalayout == EROFS_INODE_FLAT_PLAIN)
+	    (vi->datalayout == EROFS_INODE_FLAT_PLAIN ||
+	     vi->datalayout == EROFS_INODE_CHUNK_BASED))
 		inode->i_flags |= S_DAX;
 
 	if (!nblks)

fs/erofs/zdata.c

@@ -1035,7 +1035,7 @@ hitted:
 	 */
 	tight &= (fe->mode > Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE);
 
-	cur = end - min_t(unsigned int, offset + end - map->m_la, end);
+	cur = end - min_t(erofs_off_t, offset + end - map->m_la, end);
 	if (!(map->m_flags & EROFS_MAP_MAPPED)) {
 		zero_user_segment(page, cur, end);
 		goto next_part;
@@ -1841,7 +1841,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f,
 	}
 
 	cur = map->m_la + map->m_llen - 1;
-	while (cur >= end) {
+	while ((cur >= end) && (cur < i_size_read(inode))) {
 		pgoff_t index = cur >> PAGE_SHIFT;
 		struct page *page;