From e53e0882f9c3d4cee1812674d5f59ce4d6b650c4 Mon Sep 17 00:00:00 2001
From: Gleb Chesnokov <Chesnokov.G@raidix.com>
Date: Thu, 24 Mar 2022 15:48:20 +0300
Subject: [PATCH] scst_vdisk: Port to Linux kernel v5.18

Support for the following block/fs changes in the Linux Kernel v5.18:
- 609be1066731 ("block: pass a block_device and opf to bio_alloc_bioset")
- 07888c665b40 ("block: pass a block_device and opf to bio_alloc")
- cbcc268bb1ce ("fs: Move many prototypes to pagemap.h")
---
 scst/include/backport.h            | 48 ++++++++++++++++++++++++++++++
 scst/src/dev_handlers/scst_vdisk.c | 15 ++++++----
 2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/scst/include/backport.h b/scst/include/backport.h
index c357dd58d..74a4986a8 100644
--- a/scst/include/backport.h
+++ b/scst/include/backport.h
@@ -109,6 +109,54 @@ static inline void bio_set_dev(struct bio *bio, struct block_device *bdev)
 #define BIO_MAX_VECS BIO_MAX_PAGES
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 18, 0)
+/*
+ * See also commit 609be1066731 ("block: pass a block_device and opf to
+ * bio_alloc_bioset") # v5.18
+ */
+static inline
+struct bio *bio_alloc_bioset_backport(struct block_device *bdev,
+		unsigned short nr_vecs, unsigned int opf, gfp_t gfp_mask,
+		struct bio_set *bs)
+{
+	/*
+	 * Check that @bdev and @opf parameters are zeros.
+	 *
+	 * The old API expects these parameters to be set implicitly.
+	 * Therefore, warn about using an explicit setting that would
+	 * cause these parameters to be lost.
+	 */
+	WARN_ON_ONCE(bdev || opf);
+
+	return bio_alloc_bioset(gfp_mask, nr_vecs, bs);
+}
+
+#define bio_alloc_bioset bio_alloc_bioset_backport
+
+/*
+ * See also commit 07888c665b40 ("block: pass a block_device and opf to
+ * bio_alloc") # v5.18
+ */
+static inline
+struct bio *bio_alloc_backport(struct block_device *bdev,
+		unsigned short nr_vecs, unsigned int opf, gfp_t gfp_mask)
+{
+	/*
+	 * Check that @bdev and @opf parameters are zeros.
+	 *
+	 * The old API expects these parameters to be set implicitly.
+	 * Therefore, warn about using an explicit setting that would
+	 * cause these parameters to be lost.
+	 */
+	WARN_ON_ONCE(bdev || opf);
+
+	return bio_alloc(gfp_mask, nr_vecs);
+}
+
+#define bio_alloc bio_alloc_backport
+
+#endif
+
 /* <linux/blk_types.h> */
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 14, 0)
diff --git a/scst/src/dev_handlers/scst_vdisk.c b/scst/src/dev_handlers/scst_vdisk.c
index 3514fb949..8655c958a 100644
--- a/scst/src/dev_handlers/scst_vdisk.c
+++ b/scst/src/dev_handlers/scst_vdisk.c
@@ -29,6 +29,7 @@
 #include <linux/aio.h>
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/pagemap.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/unistd.h>
@@ -428,15 +429,19 @@ static int vdisk_blockio_flush(struct block_device *bdev, gfp_t gfp_mask,
 	TRACE_ENTRY();
 
 	if (async) {
-		struct bio *bio = bio_alloc(gfp_mask, 0);
+		struct bio *bio;
 
+		bio = bio_alloc(/*bdev=*/NULL, 0, /*opf=*/0, gfp_mask);
 		if (bio == NULL) {
 			res = -ENOMEM;
 			goto out_rep;
 		}
+
 		bio->bi_end_io = vdev_flush_end_io;
 		bio->bi_private = cmd;
+
 		bio_set_dev(bio, bdev);
+
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 8, 0) ||	\
 	(defined(CONFIG_SUSE_KERNEL) &&			\
 	 LINUX_VERSION_CODE >= KERNEL_VERSION(4, 4, 0))
@@ -2836,8 +2841,8 @@ static ssize_t blockio_read_sync(struct scst_vdisk_dev *virt_dev, void *buf,
 	max_nr_vecs = min(bio_get_nr_vecs(bdev), BIO_MAX_VECS);
 #endif
 
-	bio = bio_alloc_bioset(GFP_KERNEL, max_nr_vecs, virt_dev->vdisk_bioset);
-
+	bio = bio_alloc_bioset(/*bdev=*/NULL, max_nr_vecs, /*opf=*/0,
+			       GFP_KERNEL, virt_dev->vdisk_bioset);
 	if (!bio)
 		goto out;
 
@@ -5958,8 +5963,8 @@ static void blockio_exec_rw(struct vdisk_cmd_params *p, bool write, bool fua)
 			int rc;
 
 			if (need_new_bio) {
-				bio = bio_alloc_bioset(gfp_mask, max_nr_vecs, bs);
-
+				bio = bio_alloc_bioset(/*bdev=*/NULL, max_nr_vecs, /*opf=*/0,
+						       gfp_mask, bs);
 				if (!bio) {
 					PRINT_ERROR("Failed to create bio "
 						"for data segment %d (cmd %p)",