Merge tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Last minute fixes for crash on 32bit architectures when compression is
  in use. It's a regression introduced in 5.15-rc and I'd really like
  not let this into the final release, fixes via stable trees would add
  unnecessary delay.

  The problem is on 32bit architectures with highmem enabled, the pages
  for compression may need to be kmapped, while the patches removed that
  as we don't use GFP_HIGHMEM allocations anymore. The pages that don't
  come from local allocation still may be from highmem. Despite being on
  32bit there's enough such ARM machines in use so it's not a marginal
  issue.

  I did full reverts of the patches one by one instead of a huge one.
  There's one exception for the "lzo" revert as there was an
  intermediate patch touching the same code to make it compatible with
  subpage. I can't revert that one too, so the revert in lzo.c is
  manual. Qu Wenruo has worked on that with me and verified the changes"

* tag 'for-5.15-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Revert "btrfs: compression: drop kmap/kunmap from lzo"
  Revert "btrfs: compression: drop kmap/kunmap from zlib"
  Revert "btrfs: compression: drop kmap/kunmap from zstd"
  Revert "btrfs: compression: drop kmap/kunmap from generic helpers"

Author: torvalds

fs/btrfs/compression.c

@@ -172,9 +172,10 @@ static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio,
 		/* Hash through the page sector by sector */
 		for (pg_offset = 0; pg_offset < bytes_left;
 		     pg_offset += sectorsize) {
-			kaddr = page_address(page);
+			kaddr = kmap_atomic(page);
 			crypto_shash_digest(shash, kaddr + pg_offset,
 					    sectorsize, csum);
+			kunmap_atomic(kaddr);
 
 			if (memcmp(&csum, cb_sum, csum_size) != 0) {
 				btrfs_print_data_csum_error(inode, disk_start,

fs/btrfs/inode.c

@@ -287,8 +287,9 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
 			cur_size = min_t(unsigned long, compressed_size,
 				       PAGE_SIZE);
 
-			kaddr = page_address(cpage);
+			kaddr = kmap_atomic(cpage);
 			write_extent_buffer(leaf, kaddr, ptr, cur_size);
+			kunmap_atomic(kaddr);
 
 			i++;
 			ptr += cur_size;

fs/btrfs/lzo.c

@@ -141,7 +141,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 	*total_in = 0;
 
 	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
-	data_in = page_address(in_page);
+	data_in = kmap(in_page);
 
 	/*
 	 * store the size of all chunks of compressed data in
@@ -152,7 +152,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 		ret = -ENOMEM;
 		goto out;
 	}
-	cpage_out = page_address(out_page);
+	cpage_out = kmap(out_page);
 	out_offset = LZO_LEN;
 	tot_out = LZO_LEN;
 	pages[0] = out_page;
@@ -210,6 +210,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 				if (out_len == 0 && tot_in >= len)
 					break;
 
+				kunmap(out_page);
 				if (nr_pages == nr_dest_pages) {
 					out_page = NULL;
 					ret = -E2BIG;
@@ -221,7 +222,7 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 					ret = -ENOMEM;
 					goto out;
 				}
-				cpage_out = page_address(out_page);
+				cpage_out = kmap(out_page);
 				pages[nr_pages++] = out_page;
 
 				pg_bytes_left = PAGE_SIZE;
@@ -243,11 +244,12 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 			break;
 
 		bytes_left = len - tot_in;
+		kunmap(in_page);
 		put_page(in_page);
 
 		start += PAGE_SIZE;
 		in_page = find_get_page(mapping, start >> PAGE_SHIFT);
-		data_in = page_address(in_page);
+		data_in = kmap(in_page);
 		in_len = min(bytes_left, PAGE_SIZE);
 	}
 
@@ -257,17 +259,22 @@ int lzo_compress_pages(struct list_head *ws, struct address_space *mapping,
 	}
 
 	/* store the size of all chunks of compressed data */
-	sizes_ptr = page_address(pages[0]);
+	sizes_ptr = kmap_local_page(pages[0]);
 	write_compress_length(sizes_ptr, tot_out);
+	kunmap_local(sizes_ptr);
 
 	ret = 0;
 	*total_out = tot_out;
 	*total_in = tot_in;
 out:
 	*out_pages = nr_pages;
+	if (out_page)
+		kunmap(out_page);
 
-	if (in_page)
+	if (in_page) {
+		kunmap(in_page);
 		put_page(in_page);
+	}
 
 	return ret;
 }
@@ -283,16 +290,19 @@ static void copy_compressed_segment(struct compressed_bio *cb,
 	u32 orig_in = *cur_in;
 
 	while (*cur_in < orig_in + len) {
+		char *kaddr;
 		struct page *cur_page;
 		u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
 					  orig_in + len - *cur_in);
 
 		ASSERT(copy_len);
 		cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE];
 
+		kaddr = kmap(cur_page);
 		memcpy(dest + *cur_in - orig_in,
-			page_address(cur_page) + offset_in_page(*cur_in),
+			kaddr + offset_in_page(*cur_in),
 			copy_len);
+		kunmap(cur_page);
 
 		*cur_in += copy_len;
 	}
@@ -303,6 +313,7 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 	struct workspace *workspace = list_entry(ws, struct workspace, list);
 	const struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
 	const u32 sectorsize = fs_info->sectorsize;
+	char *kaddr;
 	int ret;
 	/* Compressed data length, can be unaligned */
 	u32 len_in;
@@ -311,7 +322,9 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 	/* Bytes decompressed so far */
 	u32 cur_out = 0;
 
-	len_in = read_compress_length(page_address(cb->compressed_pages[0]));
+	kaddr = kmap(cb->compressed_pages[0]);
+	len_in = read_compress_length(kaddr);
+	kunmap(cb->compressed_pages[0]);
 	cur_in += LZO_LEN;
 
 	/*
@@ -344,9 +357,9 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 		ASSERT(cur_in / sectorsize ==
 		       (cur_in + LZO_LEN - 1) / sectorsize);
 		cur_page = cb->compressed_pages[cur_in / PAGE_SIZE];
+		kaddr = kmap(cur_page);
 		ASSERT(cur_page);
-		seg_len = read_compress_length(page_address(cur_page) +
-					       offset_in_page(cur_in));
+		seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
 		cur_in += LZO_LEN;
 
 		/* Copy the compressed segment payload into workspace */
@@ -431,7 +444,7 @@ int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
 	bytes = min_t(unsigned long, destlen, out_len - start_byte);
 
-	kaddr = page_address(dest_page);
+	kaddr = kmap_local_page(dest_page);
 	memcpy(kaddr, workspace->buf + start_byte, bytes);
 
 	/*
@@ -441,6 +454,7 @@ int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 	 */
 	if (bytes < destlen)
 		memset(kaddr+bytes, 0, destlen-bytes);
+	kunmap_local(kaddr);
 out:
 	return ret;
 }

fs/btrfs/zlib.c

@@ -126,7 +126,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 		ret = -ENOMEM;
 		goto out;
 	}
-	cpage_out = page_address(out_page);
+	cpage_out = kmap(out_page);
 	pages[0] = out_page;
 	nr_pages = 1;
 
@@ -148,22 +148,26 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 				int i;
 
 				for (i = 0; i < in_buf_pages; i++) {
-					if (in_page)
+					if (in_page) {
+						kunmap(in_page);
 						put_page(in_page);
+					}
 					in_page = find_get_page(mapping,
 								start >> PAGE_SHIFT);
-					data_in = page_address(in_page);
+					data_in = kmap(in_page);
 					memcpy(workspace->buf + i * PAGE_SIZE,
 					       data_in, PAGE_SIZE);
 					start += PAGE_SIZE;
 				}
 				workspace->strm.next_in = workspace->buf;
 			} else {
-				if (in_page)
+				if (in_page) {
+					kunmap(in_page);
 					put_page(in_page);
+				}
 				in_page = find_get_page(mapping,
 							start >> PAGE_SHIFT);
-				data_in = page_address(in_page);
+				data_in = kmap(in_page);
 				start += PAGE_SIZE;
 				workspace->strm.next_in = data_in;
 			}
@@ -192,6 +196,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 		 * the stream end if required
 		 */
 		if (workspace->strm.avail_out == 0) {
+			kunmap(out_page);
 			if (nr_pages == nr_dest_pages) {
 				out_page = NULL;
 				ret = -E2BIG;
@@ -202,7 +207,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 				ret = -ENOMEM;
 				goto out;
 			}
-			cpage_out = page_address(out_page);
+			cpage_out = kmap(out_page);
 			pages[nr_pages] = out_page;
 			nr_pages++;
 			workspace->strm.avail_out = PAGE_SIZE;
@@ -229,6 +234,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 			goto out;
 		} else if (workspace->strm.avail_out == 0) {
 			/* get another page for the stream end */
+			kunmap(out_page);
 			if (nr_pages == nr_dest_pages) {
 				out_page = NULL;
 				ret = -E2BIG;
@@ -239,7 +245,7 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 				ret = -ENOMEM;
 				goto out;
 			}
-			cpage_out = page_address(out_page);
+			cpage_out = kmap(out_page);
 			pages[nr_pages] = out_page;
 			nr_pages++;
 			workspace->strm.avail_out = PAGE_SIZE;
@@ -258,8 +264,13 @@ int zlib_compress_pages(struct list_head *ws, struct address_space *mapping,
 	*total_in = workspace->strm.total_in;
 out:
 	*out_pages = nr_pages;
-	if (in_page)
+	if (out_page)
+		kunmap(out_page);
+
+	if (in_page) {
+		kunmap(in_page);
 		put_page(in_page);
+	}
 	return ret;
 }
 
@@ -276,7 +287,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 	unsigned long buf_start;
 	struct page **pages_in = cb->compressed_pages;
 
-	data_in = page_address(pages_in[page_in_index]);
+	data_in = kmap(pages_in[page_in_index]);
 	workspace->strm.next_in = data_in;
 	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
 	workspace->strm.total_in = 0;
@@ -298,6 +309,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 
 	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
 		pr_warn("BTRFS: inflateInit failed\n");
+		kunmap(pages_in[page_in_index]);
 		return -EIO;
 	}
 	while (workspace->strm.total_in < srclen) {
@@ -324,13 +336,13 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 
 		if (workspace->strm.avail_in == 0) {
 			unsigned long tmp;
-
+			kunmap(pages_in[page_in_index]);
 			page_in_index++;
 			if (page_in_index >= total_pages_in) {
 				data_in = NULL;
 				break;
 			}
-			data_in = page_address(pages_in[page_in_index]);
+			data_in = kmap(pages_in[page_in_index]);
 			workspace->strm.next_in = data_in;
 			tmp = srclen - workspace->strm.total_in;
 			workspace->strm.avail_in = min(tmp, PAGE_SIZE);
@@ -342,6 +354,8 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 		ret = 0;
 done:
 	zlib_inflateEnd(&workspace->strm);
+	if (data_in)
+		kunmap(pages_in[page_in_index]);
 	if (!ret)
 		zero_fill_bio(cb->orig_bio);
 	return ret;