diff mbox series

[5/7] block: add emulation for simple copy

Message ID 20210817101423.12367-6-selvakuma.s1@samsung.com (mailing list archive)
State New, archived
Headers show
Series [1/7] block: make bio_map_kern() non static | expand

Commit Message

SelvaKumar S Aug. 17, 2021, 10:14 a.m. UTC 
From: Nitesh Shetty <nj.shetty@samsung.com>

For the devices which does not support simple copy, copy emulation is
added. Also for stacked devices, copy is performed via emulation.

Copy-emulation is implemented by allocating maximum possible memory
less than or equal to total copy size. The source ranges are read
into memory by chaining bio for each source ranges and submitting them
async and the last bio waits for completion. After data is read, it is
written to the destination and the process is repeated till no source
ranges left.

bio_map_kern() is used to allocate bio and add pages of copy buffer to
bio. As bio->bi_private and bio->bi_end_io are needed for chaining the
bio and gets over-written, invalidate_kernel_vmap_range() for read is
called in the caller.

Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: SelvaKumar S <selvakuma.s1@samsung.com>
---
 block/blk-lib.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

Comments

kernel test robot Aug. 17, 2021, 10:10 p.m. UTC | #1 
Hi SelvaKumar,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on block/for-next]
[also build test WARNING on dm/for-next next-20210817]
[cannot apply to linus/master linux-nvme/for-next v5.14-rc6]
[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/0day-ci/linux/commits/SelvaKumar-S/block-make-bio_map_kern-non-static/20210817-193111
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: hexagon-randconfig-r013-20210816 (attached as .config)
compiler: clang version 12.0.0
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/0day-ci/linux/commit/c307f1051a72122d636502c6885df8b2b25ed697
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review SelvaKumar-S/block-make-bio_map_kern-non-static/20210817-193111
        git checkout c307f1051a72122d636502c6885df8b2b25ed697
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon 

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:197:5: warning: no previous prototype for function 'blk_copy_offload_submit_bio' [-Wmissing-prototypes]
   int blk_copy_offload_submit_bio(struct block_device *bdev,
       ^
   block/blk-lib.c:197:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int blk_copy_offload_submit_bio(struct block_device *bdev,
   ^
   static 
   block/blk-lib.c:250:5: warning: no previous prototype for function 'blk_copy_offload_scc' [-Wmissing-prototypes]
   int blk_copy_offload_scc(struct block_device *src_bdev, int nr_srcs,
       ^
   block/blk-lib.c:250:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int blk_copy_offload_scc(struct block_device *src_bdev, int nr_srcs,
   ^
   static 
>> block/blk-lib.c:336:5: 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:336:1: 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 
   3 warnings generated.


vim +/blk_submit_rw_buf +336 block/blk-lib.c

   335	
 > 336	int blk_submit_rw_buf(struct block_device *bdev, void *buf, sector_t buf_len,
   337					sector_t sector, unsigned int op, gfp_t gfp_mask)
   338	{
   339		struct request_queue *q = bdev_get_queue(bdev);
   340		struct bio *bio, *parent = NULL;
   341		sector_t max_hw_len = min_t(unsigned int, queue_max_hw_sectors(q),
   342				queue_max_segments(q) << (PAGE_SHIFT - SECTOR_SHIFT));
   343		sector_t len, remaining;
   344		int ret;
   345	
   346		for (remaining = buf_len; remaining > 0; remaining -= len) {
   347			len = min_t(int, max_hw_len, remaining);
   348	retry:
   349			bio = bio_map_kern(q, buf, len << SECTOR_SHIFT, gfp_mask);
   350			if (IS_ERR(bio)) {
   351				len >>= 1;
   352				if (len)
   353					goto retry;
   354				return PTR_ERR(bio);
   355			}
   356	
   357			bio->bi_iter.bi_sector = sector;
   358			bio->bi_opf = op;
   359			bio_set_dev(bio, bdev);
   360			bio->bi_end_io = NULL;
   361			bio->bi_private = NULL;
   362	
   363			if (parent) {
   364				bio_chain(parent, bio);
   365				submit_bio(parent);
   366			}
   367			parent = bio;
   368			sector += len;
   369		}
   370		ret = submit_bio_wait(bio);
   371		bio_put(bio);
   372	
   373		return ret;
   374	}
   375	

---
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https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
--
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diff mbox series

Patch

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 7fee0ae95c44..d29c52b90dcf 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -333,6 +333,64 @@  int blk_copy_offload_scc(struct block_device *src_bdev, int nr_srcs,
 	return ret;
 }
 
+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_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 << SECTOR_SHIFT, gfp_mask);
+		if (IS_ERR(bio)) {
+			len >>= 1;
+			if (len)
+				goto retry;
+			return PTR_ERR(bio);
+		}
+
+		bio->bi_iter.bi_sector = sector;
+		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;
+	}
+	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 >> SECTOR_SHIFT);
+			return buf;
+		}
+		/* retry half the requested size */
+		req_size >>= 1;
+	}
+
+	return NULL;
+}
+
 static inline sector_t blk_copy_len(struct range_entry *rlist, int nr_srcs)
 {
 	int i;
@@ -348,6 +406,46 @@  static inline sector_t blk_copy_len(struct range_entry *rlist, int nr_srcs)
 	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_srcs,
+		struct range_entry *rlist, struct block_device *dest_bdev,
+		sector_t dest, gfp_t gfp_mask)
+{
+	void *buf = NULL;
+	int ret, nr_i = 0;
+	sector_t src_blk, copy_len, buf_len, read_len, copied_len, remaining = 0;
+
+	copy_len = blk_copy_len(rlist, nr_srcs);
+	buf = blk_alloc_buf(copy_len << SECTOR_SHIFT, &buf_len, gfp_mask);
+	if (!buf)
+		return -ENOMEM;
+
+	for (copied_len = 0; copied_len < copy_len; copied_len += read_len) {
+		if (!remaining) {
+			src_blk = rlist[nr_i].src;
+			remaining = rlist[nr_i++].len;
+		}
+
+		read_len = min_t(sector_t, remaining, buf_len);
+		ret = blk_submit_rw_buf(src_bdev, buf, read_len, src_blk, REQ_OP_READ, gfp_mask);
+		if (ret)
+			goto out;
+		src_blk += read_len;
+		remaining -= read_len;
+		ret = blk_submit_rw_buf(dest_bdev, buf, read_len, dest + copied_len, REQ_OP_WRITE,
+				gfp_mask);
+		if (ret)
+			goto out;
+	}
+out:
+	kvfree(buf);
+	return ret;
+}
+
 static inline bool blk_check_offload_scc(struct request_queue *src_q,
 		struct request_queue *dest_q)
 {
@@ -398,6 +496,8 @@  int blkdev_issue_copy(struct block_device *src_bdev, int nr_srcs,
 
 	if (blk_check_offload_scc(src_q, dest_q))
 		ret = blk_copy_offload_scc(src_bdev, nr_srcs, src_rlist, dest_bdev, dest, gfp_mask);
+	else
+		ret = blk_copy_emulate(src_bdev, nr_srcs, src_rlist, dest_bdev, dest, gfp_mask);
 
 	return ret;
 }