diff mbox series

[v4,04/10] block: add emulation for copy

Message ID 20220426101241.30100-5-nj.shetty@samsung.com (mailing list archive)
State New, archived
Headers show
Series [v4,01/10] block: Introduce queue limits for copy-offload support | expand

Commit Message

Nitesh Shetty April 26, 2022, 10:12 a.m. UTC
For the devices which does not support copy, copy emulation is
added. Copy-emulation is implemented by reading from source ranges
into memory and writing to the corresponding destination synchronously.

Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Vincent Fu <vincent.fu@samsung.com>
Signed-off-by: Arnav Dawn <arnav.dawn@samsung.com>
---
 block/blk-lib.c        | 128 ++++++++++++++++++++++++++++++++++++++++-
 block/blk-map.c        |   2 +-
 include/linux/blkdev.h |   2 +
 3 files changed, 130 insertions(+), 2 deletions(-)

Comments

kernel test robot April 27, 2022, 1:33 a.m. UTC | #1
Hi Nitesh,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on next-20220422]
[cannot apply to axboe-block/for-next device-mapper-dm/for-next linus/master v5.18-rc4 v5.18-rc3 v5.18-rc2 v5.18-rc4]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Nitesh-Shetty/block-Introduce-queue-limits-for-copy-offload-support/20220426-201825
base:    e7d6987e09a328d4a949701db40ef63fbb970670
config: hexagon-randconfig-r041-20220425 (https://download.01.org/0day-ci/archive/20220427/202204270913.Ecb3uQx1-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/c406c5145dc7d628d4197f6726c23a3f1179b88e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Nitesh-Shetty/block-Introduce-queue-limits-for-copy-offload-support/20220426-201825
        git checkout c406c5145dc7d628d4197f6726c23a3f1179b88e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   block/blk-lib.c:178:5: warning: no previous prototype for function 'blk_copy_offload' [-Wmissing-prototypes]
   int blk_copy_offload(struct block_device *src_bdev, int nr_srcs,
       ^
   block/blk-lib.c:178:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int blk_copy_offload(struct block_device *src_bdev, int nr_srcs,
   ^
   static 
>> block/blk-lib.c:276:5: warning: no previous prototype for function 'blk_submit_rw_buf' [-Wmissing-prototypes]
   int blk_submit_rw_buf(struct block_device *bdev, void *buf, sector_t buf_len,
       ^
   block/blk-lib.c:276:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int blk_submit_rw_buf(struct block_device *bdev, void *buf, sector_t buf_len,
   ^
   static 
   2 warnings generated.


vim +/blk_submit_rw_buf +276 block/blk-lib.c

   275	
 > 276	int blk_submit_rw_buf(struct block_device *bdev, void *buf, sector_t buf_len,
   277					sector_t sector, unsigned int op, gfp_t gfp_mask)
   278	{
   279		struct request_queue *q = bdev_get_queue(bdev);
   280		struct bio *bio, *parent = NULL;
   281		sector_t max_hw_len = min_t(unsigned int, queue_max_hw_sectors(q),
   282				queue_max_segments(q) << (PAGE_SHIFT - SECTOR_SHIFT)) << SECTOR_SHIFT;
   283		sector_t len, remaining;
   284		int ret;
   285	
   286		for (remaining = buf_len; remaining > 0; remaining -= len) {
   287			len = min_t(int, max_hw_len, remaining);
   288	retry:
   289			bio = bio_map_kern(q, buf, len, gfp_mask);
   290			if (IS_ERR(bio)) {
   291				len >>= 1;
   292				if (len)
   293					goto retry;
   294				return PTR_ERR(bio);
   295			}
   296	
   297			bio->bi_iter.bi_sector = sector >> SECTOR_SHIFT;
   298			bio->bi_opf = op;
   299			bio_set_dev(bio, bdev);
   300			bio->bi_end_io = NULL;
   301			bio->bi_private = NULL;
   302	
   303			if (parent) {
   304				bio_chain(parent, bio);
   305				submit_bio(parent);
   306			}
   307			parent = bio;
   308			sector += len;
   309			buf = (char *) buf + len;
   310		}
   311		ret = submit_bio_wait(bio);
   312		bio_put(bio);
   313	
   314		return ret;
   315	}
   316
diff mbox series

Patch

diff --git a/block/blk-lib.c b/block/blk-lib.c
index ba9da2d2f429..58c30a42ea44 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -273,6 +273,65 @@  int blk_copy_offload(struct block_device *src_bdev, int nr_srcs,
 	return cio_await_completion(cio);
 }
 
+int blk_submit_rw_buf(struct block_device *bdev, void *buf, sector_t buf_len,
+				sector_t sector, unsigned int op, gfp_t gfp_mask)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+	struct bio *bio, *parent = NULL;
+	sector_t max_hw_len = min_t(unsigned int, queue_max_hw_sectors(q),
+			queue_max_segments(q) << (PAGE_SHIFT - SECTOR_SHIFT)) << SECTOR_SHIFT;
+	sector_t len, remaining;
+	int ret;
+
+	for (remaining = buf_len; remaining > 0; remaining -= len) {
+		len = min_t(int, max_hw_len, remaining);
+retry:
+		bio = bio_map_kern(q, buf, len, gfp_mask);
+		if (IS_ERR(bio)) {
+			len >>= 1;
+			if (len)
+				goto retry;
+			return PTR_ERR(bio);
+		}
+
+		bio->bi_iter.bi_sector = sector >> SECTOR_SHIFT;
+		bio->bi_opf = op;
+		bio_set_dev(bio, bdev);
+		bio->bi_end_io = NULL;
+		bio->bi_private = NULL;
+
+		if (parent) {
+			bio_chain(parent, bio);
+			submit_bio(parent);
+		}
+		parent = bio;
+		sector += len;
+		buf = (char *) buf + len;
+	}
+	ret = submit_bio_wait(bio);
+	bio_put(bio);
+
+	return ret;
+}
+
+static void *blk_alloc_buf(sector_t req_size, sector_t *alloc_size, gfp_t gfp_mask)
+{
+	int min_size = PAGE_SIZE;
+	void *buf;
+
+	while (req_size >= min_size) {
+		buf = kvmalloc(req_size, gfp_mask);
+		if (buf) {
+			*alloc_size = req_size;
+			return buf;
+		}
+		/* retry half the requested size */
+		req_size >>= 1;
+	}
+
+	return NULL;
+}
+
 static inline int blk_copy_sanity_check(struct block_device *src_bdev,
 		struct block_device *dst_bdev, struct range_entry *rlist, int nr)
 {
@@ -298,6 +357,68 @@  static inline int blk_copy_sanity_check(struct block_device *src_bdev,
 	return 0;
 }
 
+/* returns the total copy length still need to be copied */
+static inline sector_t blk_copy_max_range(struct range_entry *rlist, int nr, sector_t *max_len)
+{
+	int i;
+	sector_t len = 0;
+
+	*max_len = 0;
+	for (i = 0; i < nr; i++) {
+		*max_len = max(*max_len, rlist[i].len - rlist[i].comp_len);
+		len += (rlist[i].len - rlist[i].comp_len);
+	}
+
+	return len;
+}
+
+/*
+ * If native copy offload feature is absent, this function tries to emulate,
+ * by copying data from source to a temporary buffer and from buffer to
+ * destination device.
+ */
+static int blk_copy_emulate(struct block_device *src_bdev, int nr,
+		struct range_entry *rlist, struct block_device *dest_bdev, gfp_t gfp_mask)
+{
+	void *buf = NULL;
+	int ret, nr_i = 0;
+	sector_t src, dst, copy_len, buf_len, read_len, copied_len,
+		 max_len = 0, remaining = 0, offset = 0;
+
+	copy_len = blk_copy_max_range(rlist, nr, &max_len);
+	buf = blk_alloc_buf(max_len, &buf_len, gfp_mask);
+	if (!buf)
+		return -ENOMEM;
+
+	for (copied_len = 0; copied_len < copy_len; copied_len += read_len) {
+		if (!remaining) {
+			offset = rlist[nr_i].comp_len;
+			src = rlist[nr_i].src + offset;
+			dst = rlist[nr_i].dst + offset;
+			remaining = rlist[nr_i++].len - offset;
+		}
+
+		read_len = min_t(sector_t, remaining, buf_len);
+		if (!read_len)
+			continue;
+		ret = blk_submit_rw_buf(src_bdev, buf, read_len, src, REQ_OP_READ, gfp_mask);
+		if (ret)
+			goto out;
+		src += read_len;
+		remaining -= read_len;
+		ret = blk_submit_rw_buf(dest_bdev, buf, read_len, dst, REQ_OP_WRITE,
+				gfp_mask);
+		if (ret)
+			goto out;
+		else
+			rlist[nr_i - 1].comp_len += read_len;
+		dst += read_len;
+	}
+out:
+	kvfree(buf);
+	return ret;
+}
+
 static inline bool blk_check_copy_offload(struct request_queue *src_q,
 		struct request_queue *dest_q)
 {
@@ -325,6 +446,7 @@  int blkdev_issue_copy(struct block_device *src_bdev, int nr,
 	struct request_queue *src_q = bdev_get_queue(src_bdev);
 	struct request_queue *dest_q = bdev_get_queue(dest_bdev);
 	int ret = -EINVAL;
+	bool offload = false;
 
 	if (!src_q || !dest_q)
 		return -ENXIO;
@@ -342,9 +464,13 @@  int blkdev_issue_copy(struct block_device *src_bdev, int nr,
 	if (ret)
 		return ret;
 
-	if (blk_check_copy_offload(src_q, dest_q))
+	offload = blk_check_copy_offload(src_q, dest_q);
+	if (offload)
 		ret = blk_copy_offload(src_bdev, nr, rlist, dest_bdev, gfp_mask);
 
+	if (ret || !offload)
+		ret = blk_copy_emulate(src_bdev, nr, rlist, dest_bdev, gfp_mask);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(blkdev_issue_copy);
diff --git a/block/blk-map.c b/block/blk-map.c
index 7ffde64f9019..ca2ad2c21f42 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -340,7 +340,7 @@  static void bio_map_kern_endio(struct bio *bio)
  *	Map the kernel address into a bio suitable for io to a block
  *	device. Returns an error pointer in case of error.
  */
-static struct bio *bio_map_kern(struct request_queue *q, void *data,
+struct bio *bio_map_kern(struct request_queue *q, void *data,
 		unsigned int len, gfp_t gfp_mask)
 {
 	unsigned long kaddr = (unsigned long)data;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c6cb3fe82ba2..ea1f3c8f8dad 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1121,6 +1121,8 @@  int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop);
 int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp);
+struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
+		gfp_t gfp_mask);
 int blkdev_issue_copy(struct block_device *src_bdev, int nr_srcs,
 		struct range_entry *src_rlist, struct block_device *dest_bdev, gfp_t gfp_mask);