[PATCHv2 0/6] enable bs > ps for block devices

[PATCHv2 0/6] enable bs > ps for block devices

[Hannes Reinecke]

Hi all,

based on the patch series from Pankaj '[PATCH v5 00/11] enable bs > ps in XFS'
it's now quite simple to enable support for block devices with block sizes
larger than page size even without having to disable CONFIG_BUFFER_HEAD.
The patchset really is just two rather trivial patches to fs/mpage,
and two patches to remove hardcoded restrictions on the block size.

As usual, comments and reviews are welcome.

Changes to the original submission:
- Include reviews from Matthew
- Include reviews from Luis
- Fixup crash in bio_split()

Hannes Reinecke (5):
  fs/mpage: avoid negative shift for large blocksize
  fs/mpage: use blocks_per_folio instead of blocks_per_page
  blk-merge: split bio by max_segment_size, not PAGE_SIZE
  block/bdev: enable large folio support for large logical block sizes
  block/bdev: lift restrictions on supported blocksize

Pankaj Raghav (1):
  nvme: enable logical block size > PAGE_SIZE

 block/bdev.c             | 11 ++++++---
 block/blk-merge.c        |  3 ++-
 drivers/nvme/host/core.c |  8 +++----
 fs/mpage.c               | 49 +++++++++++++++++++---------------------
 4 files changed, 37 insertions(+), 34 deletions(-)

-- 
2.35.3

[PATCH 1/6] fs/mpage: avoid negative shift for large blocksize

[Hannes Reinecke]

For large blocksizes the number of block bits is larger than PAGE_SHIFT,
so use folio_pos() to calculate the sector number from the folio.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 fs/mpage.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/mpage.c b/fs/mpage.c
index fa8b99a199fa..558b627d382c 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -188,7 +188,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	if (folio_buffers(folio))
 		goto confused;
 
-	block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
+	block_in_file = folio_pos(folio) >> blkbits;
 	last_block = block_in_file + args->nr_pages * blocks_per_page;
 	last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
 	if (last_block > last_block_in_file)
@@ -534,7 +534,7 @@ static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
 	 * The page has no buffers: map it to disk
 	 */
 	BUG_ON(!folio_test_uptodate(folio));
-	block_in_file = (sector_t)folio->index << (PAGE_SHIFT - blkbits);
+	block_in_file = folio_pos(folio) >> blkbits;
 	/*
 	 * Whole page beyond EOF? Skip allocating blocks to avoid leaking
 	 * space.
-- 
2.35.3

[PATCH 2/6] fs/mpage: use blocks_per_folio instead of blocks_per_page

[Hannes Reinecke]

Convert mpage to folios and associate the number of blocks with
a folio and not a page.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 fs/mpage.c | 45 +++++++++++++++++++++------------------------
 1 file changed, 21 insertions(+), 24 deletions(-)

diff --git a/fs/mpage.c b/fs/mpage.c
index 558b627d382c..7cb9d9efdba8 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -114,7 +114,7 @@ static void map_buffer_to_folio(struct folio *folio, struct buffer_head *bh,
 		 * don't make any buffers if there is only one buffer on
 		 * the folio and the folio just needs to be set up to date
 		 */
-		if (inode->i_blkbits == PAGE_SHIFT &&
+		if (inode->i_blkbits == folio_shift(folio) &&
 		    buffer_uptodate(bh)) {
 			folio_mark_uptodate(folio);
 			return;
@@ -160,7 +160,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	struct folio *folio = args->folio;
 	struct inode *inode = folio->mapping->host;
 	const unsigned blkbits = inode->i_blkbits;
-	const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
+	const unsigned blocks_per_folio = folio_size(folio) >> blkbits;
 	const unsigned blocksize = 1 << blkbits;
 	struct buffer_head *map_bh = &args->map_bh;
 	sector_t block_in_file;
@@ -168,7 +168,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	sector_t last_block_in_file;
 	sector_t first_block;
 	unsigned page_block;
-	unsigned first_hole = blocks_per_page;
+	unsigned first_hole = blocks_per_folio;
 	struct block_device *bdev = NULL;
 	int length;
 	int fully_mapped = 1;
@@ -177,9 +177,6 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	unsigned relative_block;
 	gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL);
 
-	/* MAX_BUF_PER_PAGE, for example */
-	VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
-
 	if (args->is_readahead) {
 		opf |= REQ_RAHEAD;
 		gfp |= __GFP_NORETRY | __GFP_NOWARN;
@@ -189,7 +186,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 		goto confused;
 
 	block_in_file = folio_pos(folio) >> blkbits;
-	last_block = block_in_file + args->nr_pages * blocks_per_page;
+	last_block = block_in_file + ((args->nr_pages * PAGE_SIZE) >> blkbits);
 	last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
 	if (last_block > last_block_in_file)
 		last_block = last_block_in_file;
@@ -211,7 +208,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 				clear_buffer_mapped(map_bh);
 				break;
 			}
-			if (page_block == blocks_per_page)
+			if (page_block == blocks_per_folio)
 				break;
 			page_block++;
 			block_in_file++;
@@ -223,7 +220,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	 * Then do more get_blocks calls until we are done with this folio.
 	 */
 	map_bh->b_folio = folio;
-	while (page_block < blocks_per_page) {
+	while (page_block < blocks_per_folio) {
 		map_bh->b_state = 0;
 		map_bh->b_size = 0;
 
@@ -236,7 +233,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 
 		if (!buffer_mapped(map_bh)) {
 			fully_mapped = 0;
-			if (first_hole == blocks_per_page)
+			if (first_hole == blocks_per_folio)
 				first_hole = page_block;
 			page_block++;
 			block_in_file++;
@@ -254,7 +251,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 			goto confused;
 		}
 	
-		if (first_hole != blocks_per_page)
+		if (first_hole != blocks_per_folio)
 			goto confused;		/* hole -> non-hole */
 
 		/* Contiguous blocks? */
@@ -267,7 +264,7 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 			if (relative_block == nblocks) {
 				clear_buffer_mapped(map_bh);
 				break;
-			} else if (page_block == blocks_per_page)
+			} else if (page_block == blocks_per_folio)
 				break;
 			page_block++;
 			block_in_file++;
@@ -275,8 +272,8 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 		bdev = map_bh->b_bdev;
 	}
 
-	if (first_hole != blocks_per_page) {
-		folio_zero_segment(folio, first_hole << blkbits, PAGE_SIZE);
+	if (first_hole != blocks_per_folio) {
+		folio_zero_segment(folio, first_hole << blkbits, folio_size(folio));
 		if (first_hole == 0) {
 			folio_mark_uptodate(folio);
 			folio_unlock(folio);
@@ -310,10 +307,10 @@ static struct bio *do_mpage_readpage(struct mpage_readpage_args *args)
 	relative_block = block_in_file - args->first_logical_block;
 	nblocks = map_bh->b_size >> blkbits;
 	if ((buffer_boundary(map_bh) && relative_block == nblocks) ||
-	    (first_hole != blocks_per_page))
+	    (first_hole != blocks_per_folio))
 		args->bio = mpage_bio_submit_read(args->bio);
 	else
-		args->last_block_in_bio = first_block + blocks_per_page - 1;
+		args->last_block_in_bio = first_block + blocks_per_folio - 1;
 out:
 	return args->bio;
 
@@ -392,7 +389,7 @@ int mpage_read_folio(struct folio *folio, get_block_t get_block)
 {
 	struct mpage_readpage_args args = {
 		.folio = folio,
-		.nr_pages = 1,
+		.nr_pages = folio_nr_pages(folio),
 		.get_block = get_block,
 	};
 
@@ -463,12 +460,12 @@ static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
 	struct address_space *mapping = folio->mapping;
 	struct inode *inode = mapping->host;
 	const unsigned blkbits = inode->i_blkbits;
-	const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
+	const unsigned blocks_per_folio = folio_size(folio) >> blkbits;
 	sector_t last_block;
 	sector_t block_in_file;
 	sector_t first_block;
 	unsigned page_block;
-	unsigned first_unmapped = blocks_per_page;
+	unsigned first_unmapped = blocks_per_folio;
 	struct block_device *bdev = NULL;
 	int boundary = 0;
 	sector_t boundary_block = 0;
@@ -493,12 +490,12 @@ static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
 				 */
 				if (buffer_dirty(bh))
 					goto confused;
-				if (first_unmapped == blocks_per_page)
+				if (first_unmapped == blocks_per_folio)
 					first_unmapped = page_block;
 				continue;
 			}
 
-			if (first_unmapped != blocks_per_page)
+			if (first_unmapped != blocks_per_folio)
 				goto confused;	/* hole -> non-hole */
 
 			if (!buffer_dirty(bh) || !buffer_uptodate(bh))
@@ -543,7 +540,7 @@ static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
 		goto page_is_mapped;
 	last_block = (i_size - 1) >> blkbits;
 	map_bh.b_folio = folio;
-	for (page_block = 0; page_block < blocks_per_page; ) {
+	for (page_block = 0; page_block < blocks_per_folio; ) {
 
 		map_bh.b_state = 0;
 		map_bh.b_size = 1 << blkbits;
@@ -625,14 +622,14 @@ static int __mpage_writepage(struct folio *folio, struct writeback_control *wbc,
 	BUG_ON(folio_test_writeback(folio));
 	folio_start_writeback(folio);
 	folio_unlock(folio);
-	if (boundary || (first_unmapped != blocks_per_page)) {
+	if (boundary || (first_unmapped != blocks_per_folio)) {
 		bio = mpage_bio_submit_write(bio);
 		if (boundary_block) {
 			write_boundary_block(boundary_bdev,
 					boundary_block, 1 << blkbits);
 		}
 	} else {
-		mpd->last_block_in_bio = first_block + blocks_per_page - 1;
+		mpd->last_block_in_bio = first_block + blocks_per_folio - 1;
 	}
 	goto out;
 
-- 
2.35.3

[PATCH 3/6] blk-merge: split bio by max_segment_size, not PAGE_SIZE

[Hannes Reinecke]

Bvecs can be larger than a page, and the block layer handles
this just fine. So do not split by PAGE_SIZE but rather by
the max_segment_size if that happens to be larger.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 block/blk-merge.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 4e3483a16b75..570573d7a34f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -278,6 +278,7 @@ struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
 	struct bio_vec bv, bvprv, *bvprvp = NULL;
 	struct bvec_iter iter;
 	unsigned nsegs = 0, bytes = 0;
+	unsigned bv_seg_lim = max(PAGE_SIZE, lim->max_segment_size);
 
 	bio_for_each_bvec(bv, bio, iter) {
 		/*
@@ -289,7 +290,7 @@ struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
 
 		if (nsegs < lim->max_segments &&
 		    bytes + bv.bv_len <= max_bytes &&
-		    bv.bv_offset + bv.bv_len <= PAGE_SIZE) {
+		    bv.bv_offset + bv.bv_len <= bv_seg_lim) {
 			nsegs++;
 			bytes += bv.bv_len;
 		} else {
-- 
2.35.3

[PATCH 4/6] block/bdev: enable large folio support for large logical block sizes

[Hannes Reinecke]

Call mapping_set_folio_min_order() when modifying the logical block
size to ensure folios are allocated with the correct size.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 block/bdev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block/bdev.c b/block/bdev.c
index b8e32d933a63..bd2efcad4f32 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -142,6 +142,8 @@ static void set_init_blocksize(struct block_device *bdev)
 		bsize <<= 1;
 	}
 	bdev->bd_inode->i_blkbits = blksize_bits(bsize);
+	mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
+				    get_order(bsize));
 }
 
 int set_blocksize(struct block_device *bdev, int size)
@@ -158,6 +160,8 @@ int set_blocksize(struct block_device *bdev, int size)
 	if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
 		sync_blockdev(bdev);
 		bdev->bd_inode->i_blkbits = blksize_bits(size);
+		mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
+					    get_order(size));
 		kill_bdev(bdev);
 	}
 	return 0;
-- 
2.35.3

[PATCH 5/6] block/bdev: lift restrictions on supported blocksize

[Hannes Reinecke]

We now can support blocksizes larger than PAGE_SIZE, so lift
the restriction.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 block/bdev.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index bd2efcad4f32..f092a1b04629 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -148,8 +148,9 @@ static void set_init_blocksize(struct block_device *bdev)
 
 int set_blocksize(struct block_device *bdev, int size)
 {
-	/* Size must be a power of two, and between 512 and PAGE_SIZE */
-	if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
+	/* Size must be a power of two, and between 512 and MAX_PAGECACHE_ORDER*/
+	if (get_order(bs) > MAX_PAGECACHE_ORDER || size < 512 ||
+	    !is_power_of_2(size))
 		return -EINVAL;
 
 	/* Size cannot be smaller than the size supported by the device */
@@ -174,7 +175,7 @@ int sb_set_blocksize(struct super_block *sb, int size)
 	if (set_blocksize(sb->s_bdev, size))
 		return 0;
 	/* If we get here, we know size is power of two
-	 * and it's value is between 512 and PAGE_SIZE */
+	 * and it's value is larger than 512 */
 	sb->s_blocksize = size;
 	sb->s_blocksize_bits = blksize_bits(size);
 	return sb->s_blocksize;
-- 
2.35.3

[PATCH 6/6] nvme: enable logical block size > PAGE_SIZE

[Hannes Reinecke]

From: Pankaj Raghav <p.raghav@samsung.com>

Don't set the capacity to zero for when logical block size > PAGE_SIZE
as the block device with iomap aops support allocating block cache with
a minimum folio order.

Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/nvme/host/core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 828c77fa13b7..111bf4197052 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1963,11 +1963,11 @@ static bool nvme_update_disk_info(struct nvme_ns *ns, struct nvme_id_ns *id,
 	bool valid = true;
 
 	/*
-	 * The block layer can't support LBA sizes larger than the page size
-	 * or smaller than a sector size yet, so catch this early and don't
-	 * allow block I/O.
+	 * The block layer can't support LBA sizes larger than
+	 * MAX_PAGECACHE_ORDER or smaller than a sector size, so catch this
+	 * early and don't allow block I/O.
 	 */
-	if (head->lba_shift > PAGE_SHIFT || head->lba_shift < SECTOR_SHIFT) {
+	if (get_order(bs) > MAX_PAGECACHE_ORDER || head->lba_shift < SECTOR_SHIFT) {
 		bs = (1 << 9);
 		valid = false;
 	}
-- 
2.35.3

Re: [PATCH 3/6] blk-merge: split bio by max_segment_size, not PAGE_SIZE

[John Garry]

On 14/05/2024 11:38, Hannes Reinecke wrote:
> Bvecs can be larger than a page, and the block layer handles
> this just fine. So do not split by PAGE_SIZE but rather by
> the max_segment_size if that happens to be larger.
Can you check scsi_debug for this series? I took this series only up to 
this change, and got:

     Startin[    1.736470] ------------[ cut here ]------------
g Load [    1.737777] WARNING: CPU: 0 PID: 52 at block/blk-merge.c:581 
__blk_rq_map_sg+0x46a/0x480
Kernel Module fu[    1.738862] Modules linked in:
se...[    1.739370] CPU: 0 PID: 52 Comm: kworker/0:1H Not tainted 
6.9.0-00002-g4eaa50af9312-dirty #2416

[    1.740474] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 
rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[    1.741809] Workqueue: kblockd blk_mq_run_work_fn
[    1.742379] RIP: 0010:__blk_rq_map_sg+0x46a/0x480
[    1.742939] Code: 17 fe ff ff 44 89 58 0c 48 8b 01 e9 ec fc ff ff 43 
8d 3c 06 48 8b 14 24 81 ff 00 10 00 00 0f 86 af fc ff ff e9 02 f0
[    1.743015] systemd[1]: File System Check on Root Device was skipped 
because of a failed condition check (ConditionPathIsReadWrite=!/.
[    1.745122] RSP: 0018:ff37636e4032bb90 EFLAGS: 00010212
[    1.746419] systemd[1]: systemd-journald.service: unit configures an 
IP firewall, but the local system does not support BPF/cgroup fi.
[    1.746891] RAX: 000000000000001c RBX: 00000000000001b0 RCX: 
ff28e6d8b0950a00
[    1.747903] systemd[1]: (This warning is only shown for the first 
unit using IP firewalling.)
[    1.748549] RDX: ff7662becb4ac482 RSI: 0000000000001000 RDI: 
00000000fffffffd
[    1.749688] systemd[1]: Starting Journal Service...
[    1.749895] RBP: ff7662becb4abf80 R08: 0000000000000000 R09: 
ff28e6d880fadd40
[    1.750965] R10: ff7662becb4ac480 R11: 0000000000000000 R12: 
0000000000000000
[    1.750966] R13: 0000000000000002 R14: 0000000000001000 R15: 
ff7662becb4ac480
[    1.750970] FS:  0000000000000000(0000) GS:ff28e6da75c00000(0000) 
knlGS:0000000000000000
[    1.750972] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.750973] CR2: 00007f7407f19000 CR3: 0000000100f24002 CR4: 
0000000000771ef0
[    1.750974] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
0000000000000000
[    1.750975] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 
0000000000000400
[    1.750976] PKRU: 55555554
[    1.750977] Call Trace:
[    1.750984]  <TASK>
[    1.750986]  ? __warn+0x7e/0x130
[    1.750992]  ? __blk_rq_map_sg+0x46a/0x480
[    1.750994]  ? report_bug+0x18e/0x1a0
[    1.750999]  ? handle_bug+0x3d/0x70
[    1.751003]  ? exc_invalid_op+0x18/0x70
[    1.751006]  ? asm_exc_invalid_op+0x1a/0x20
[    1.751009]  ? __blk_rq_map_sg+0x46a/0x480
[    1.751012]  scsi_alloc_sgtables+0xb7/0x3f0
[    1.751019]  sd_init_command+0x177/0x9d0
[    1.751023]  scsi_queue_rq+0x7c1/0xae0
[    1.751027]  blk_mq_dispatch_rq_list+0x2bc/0x7c0
[    1.751031]  __blk_mq_sched_dispatch_requests+0x409/0x5c0
[    1.751035]  blk_mq_sched_dispatch_requests+0x2c/0x60
[    1.751037]  blk_mq_run_work_fn+0x5f/0x70
[    1.751039]  process_one_work+0x149/0x360

I suspect that you would need to also change the PAGE_SIZE check in 
__blk_bios_map_sg() also. However, I am not confident that the change 
below is ok to begin with...

BTW, scsi_debug does use an insane max_segment_size of -1

> 
> Signed-off-by: Hannes Reinecke <hare@kernel.org>
> ---
>   block/blk-merge.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 4e3483a16b75..570573d7a34f 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -278,6 +278,7 @@ struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
>   	struct bio_vec bv, bvprv, *bvprvp = NULL;
>   	struct bvec_iter iter;
>   	unsigned nsegs = 0, bytes = 0;
> +	unsigned bv_seg_lim = max(PAGE_SIZE, lim->max_segment_size);
>   
>   	bio_for_each_bvec(bv, bio, iter) {
>   		/*
> @@ -289,7 +290,7 @@ struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,
>   
>   		if (nsegs < lim->max_segments &&
>   		    bytes + bv.bv_len <= max_bytes &&
> -		    bv.bv_offset + bv.bv_len <= PAGE_SIZE) {
> +		    bv.bv_offset + bv.bv_len <= bv_seg_lim) {
>   			nsegs++;
>   			bytes += bv.bv_len;
>   		} else {

Re: [PATCH 5/6] block/bdev: lift restrictions on supported blocksize

[kernel test robot]

Hi Hannes,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linus/master v6.9]
[cannot apply to next-20240514]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Hannes-Reinecke/fs-mpage-avoid-negative-shift-for-large-blocksize/20240515-014146
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20240514173900.62207-6-hare%40kernel.org
patch subject: [PATCH 5/6] block/bdev: lift restrictions on supported blocksize
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20240515/202405150852.LoiNtqk4-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project b910bebc300dafb30569cecc3017b446ea8eafa0)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240515/202405150852.LoiNtqk4-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405150852.LoiNtqk4-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from block/bdev.c:9:
   In file included from include/linux/mm.h:2210:
   include/linux/vmstat.h:522:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     522 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from block/bdev.c:15:
   In file included from include/linux/blk-integrity.h:5:
   In file included from include/linux/blk-mq.h:8:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     547 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     560 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
         |                                                           ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
     102 | #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
         |                                                      ^
   In file included from block/bdev.c:15:
   In file included from include/linux/blk-integrity.h:5:
   In file included from include/linux/blk-mq.h:8:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     573 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
         |                                                           ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
     115 | #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
         |                                                      ^
   In file included from block/bdev.c:15:
   In file included from include/linux/blk-integrity.h:5:
   In file included from include/linux/blk-mq.h:8:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:78:
   include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     584 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     594 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     604 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:692:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     692 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:700:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     700 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:708:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     708 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:717:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     717 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:726:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     726 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     735 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   block/bdev.c:145:2: error: call to undeclared function 'mapping_set_folio_min_order'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     145 |         mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
         |         ^
>> block/bdev.c:152:16: error: use of undeclared identifier 'bs'
     152 |         if (get_order(bs) > MAX_PAGECACHE_ORDER || size < 512 ||
         |                       ^
   block/bdev.c:164:3: error: call to undeclared function 'mapping_set_folio_min_order'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     164 |                 mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
         |                 ^
   13 warnings and 3 errors generated.


vim +/bs +152 block/bdev.c

   148	
   149	int set_blocksize(struct block_device *bdev, int size)
   150	{
   151		/* Size must be a power of two, and between 512 and MAX_PAGECACHE_ORDER*/
 > 152		if (get_order(bs) > MAX_PAGECACHE_ORDER || size < 512 ||
   153		    !is_power_of_2(size))
   154			return -EINVAL;
   155	
   156		/* Size cannot be smaller than the size supported by the device */
   157		if (size < bdev_logical_block_size(bdev))
   158			return -EINVAL;
   159	
   160		/* Don't change the size if it is same as current */
   161		if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
   162			sync_blockdev(bdev);
   163			bdev->bd_inode->i_blkbits = blksize_bits(size);
   164			mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
   165						    get_order(size));
   166			kill_bdev(bdev);
   167		}
   168		return 0;
   169	}
   170	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 5/6] block/bdev: lift restrictions on supported blocksize

[kernel test robot]

Hi Hannes,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linus/master v6.9]
[cannot apply to next-20240514]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Hannes-Reinecke/fs-mpage-avoid-negative-shift-for-large-blocksize/20240515-014146
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20240514173900.62207-6-hare%40kernel.org
patch subject: [PATCH 5/6] block/bdev: lift restrictions on supported blocksize
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20240515/202405151142.8COQSJsa-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240515/202405151142.8COQSJsa-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405151142.8COQSJsa-lkp@intel.com/

All errors (new ones prefixed by >>):

   block/bdev.c: In function 'set_init_blocksize':
   block/bdev.c:145:9: error: implicit declaration of function 'mapping_set_folio_min_order' [-Werror=implicit-function-declaration]
     145 |         mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   block/bdev.c: In function 'set_blocksize':
>> block/bdev.c:152:23: error: 'bs' undeclared (first use in this function); did you mean 'abs'?
     152 |         if (get_order(bs) > MAX_PAGECACHE_ORDER || size < 512 ||
         |                       ^~
         |                       abs
   block/bdev.c:152:23: note: each undeclared identifier is reported only once for each function it appears in
   cc1: some warnings being treated as errors


vim +152 block/bdev.c

   148	
   149	int set_blocksize(struct block_device *bdev, int size)
   150	{
   151		/* Size must be a power of two, and between 512 and MAX_PAGECACHE_ORDER*/
 > 152		if (get_order(bs) > MAX_PAGECACHE_ORDER || size < 512 ||
   153		    !is_power_of_2(size))
   154			return -EINVAL;
   155	
   156		/* Size cannot be smaller than the size supported by the device */
   157		if (size < bdev_logical_block_size(bdev))
   158			return -EINVAL;
   159	
   160		/* Don't change the size if it is same as current */
   161		if (bdev->bd_inode->i_blkbits != blksize_bits(size)) {
   162			sync_blockdev(bdev);
   163			bdev->bd_inode->i_blkbits = blksize_bits(size);
   164			mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
   165						    get_order(size));
   166			kill_bdev(bdev);
   167		}
   168		return 0;
   169	}
   170	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 4/6] block/bdev: enable large folio support for large logical block sizes

[kernel test robot]

Hi Hannes,

kernel test robot noticed the following build errors:

[auto build test ERROR on axboe-block/for-next]
[also build test ERROR on linus/master v6.9]
[cannot apply to next-20240514]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Hannes-Reinecke/fs-mpage-avoid-negative-shift-for-large-blocksize/20240515-014146
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20240514173900.62207-5-hare%40kernel.org
patch subject: [PATCH 4/6] block/bdev: enable large folio support for large logical block sizes
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20240515/202405151219.H2vlwtc0-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240515/202405151219.H2vlwtc0-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202405151219.H2vlwtc0-lkp@intel.com/

All errors (new ones prefixed by >>):

>> block/bdev.c:145:2: error: call to undeclared function 'mapping_set_folio_min_order'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     145 |         mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
         |         ^
   block/bdev.c:163:3: error: call to undeclared function 'mapping_set_folio_min_order'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     163 |                 mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
         |                 ^
   2 errors generated.


vim +/mapping_set_folio_min_order +145 block/bdev.c

   133	
   134	static void set_init_blocksize(struct block_device *bdev)
   135	{
   136		unsigned int bsize = bdev_logical_block_size(bdev);
   137		loff_t size = i_size_read(bdev->bd_inode);
   138	
   139		while (bsize < PAGE_SIZE) {
   140			if (size & bsize)
   141				break;
   142			bsize <<= 1;
   143		}
   144		bdev->bd_inode->i_blkbits = blksize_bits(bsize);
 > 145		mapping_set_folio_min_order(bdev->bd_inode->i_mapping,
   146					    get_order(bsize));
   147	}
   148	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 3/6] blk-merge: split bio by max_segment_size, not PAGE_SIZE

[Hannes Reinecke]

On 5/15/24 02:20, John Garry wrote:
> On 14/05/2024 11:38, Hannes Reinecke wrote:
>> Bvecs can be larger than a page, and the block layer handles
>> this just fine. So do not split by PAGE_SIZE but rather by
>> the max_segment_size if that happens to be larger.
> Can you check scsi_debug for this series? I took this series only up to 
> this change, and got:
> 
>      Startin[    1.736470] ------------[ cut here ]------------
> g Load [    1.737777] WARNING: CPU: 0 PID: 52 at block/blk-merge.c:581 
> __blk_rq_map_sg+0x46a/0x480
> Kernel Module fu[    1.738862] Modules linked in:
> se...[    1.739370] CPU: 0 PID: 52 Comm: kworker/0:1H Not tainted 
> 6.9.0-00002-g4eaa50af9312-dirty #2416
> 
> [    1.740474] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 
> rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
> [    1.741809] Workqueue: kblockd blk_mq_run_work_fn
> [    1.742379] RIP: 0010:__blk_rq_map_sg+0x46a/0x480
> [    1.742939] Code: 17 fe ff ff 44 89 58 0c 48 8b 01 e9 ec fc ff ff 43 
> 8d 3c 06 48 8b 14 24 81 ff 00 10 00 00 0f 86 af fc ff ff e9 02 f0
> [    1.743015] systemd[1]: File System Check on Root Device was skipped 
> because of a failed condition check (ConditionPathIsReadWrite=!/.
> [    1.745122] RSP: 0018:ff37636e4032bb90 EFLAGS: 00010212
> [    1.746419] systemd[1]: systemd-journald.service: unit configures an 
> IP firewall, but the local system does not support BPF/cgroup fi.
> [    1.746891] RAX: 000000000000001c RBX: 00000000000001b0 RCX: 
> ff28e6d8b0950a00
> [    1.747903] systemd[1]: (This warning is only shown for the first 
> unit using IP firewalling.)
> [    1.748549] RDX: ff7662becb4ac482 RSI: 0000000000001000 RDI: 
> 00000000fffffffd
> [    1.749688] systemd[1]: Starting Journal Service...
> [    1.749895] RBP: ff7662becb4abf80 R08: 0000000000000000 R09: 
> ff28e6d880fadd40
> [    1.750965] R10: ff7662becb4ac480 R11: 0000000000000000 R12: 
> 0000000000000000
> [    1.750966] R13: 0000000000000002 R14: 0000000000001000 R15: 
> ff7662becb4ac480
> [    1.750970] FS:  0000000000000000(0000) GS:ff28e6da75c00000(0000) 
> knlGS:0000000000000000
> [    1.750972] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [    1.750973] CR2: 00007f7407f19000 CR3: 0000000100f24002 CR4: 
> 0000000000771ef0
> [    1.750974] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
> 0000000000000000
> [    1.750975] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 
> 0000000000000400
> [    1.750976] PKRU: 55555554
> [    1.750977] Call Trace:
> [    1.750984]  <TASK>
> [    1.750986]  ? __warn+0x7e/0x130
> [    1.750992]  ? __blk_rq_map_sg+0x46a/0x480
> [    1.750994]  ? report_bug+0x18e/0x1a0
> [    1.750999]  ? handle_bug+0x3d/0x70
> [    1.751003]  ? exc_invalid_op+0x18/0x70
> [    1.751006]  ? asm_exc_invalid_op+0x1a/0x20
> [    1.751009]  ? __blk_rq_map_sg+0x46a/0x480
> [    1.751012]  scsi_alloc_sgtables+0xb7/0x3f0
> [    1.751019]  sd_init_command+0x177/0x9d0
> [    1.751023]  scsi_queue_rq+0x7c1/0xae0
> [    1.751027]  blk_mq_dispatch_rq_list+0x2bc/0x7c0
> [    1.751031]  __blk_mq_sched_dispatch_requests+0x409/0x5c0
> [    1.751035]  blk_mq_sched_dispatch_requests+0x2c/0x60
> [    1.751037]  blk_mq_run_work_fn+0x5f/0x70
> [    1.751039]  process_one_work+0x149/0x360
> 
> I suspect that you would need to also change the PAGE_SIZE check in 
> __blk_bios_map_sg() also. However, I am not confident that the change 
> below is ok to begin with...
> 
> BTW, scsi_debug does use an insane max_segment_size of -1
> 
Can you try with this patch?

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 570573d7a34f..5da63180069e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -278,7 +278,10 @@ struct bio *bio_split_rw(struct bio *bio, const 
struct queue_limits *lim,
         struct bio_vec bv, bvprv, *bvprvp = NULL;
         struct bvec_iter iter;
         unsigned nsegs = 0, bytes = 0;
-       unsigned bv_seg_lim = max(PAGE_SIZE, lim->max_segment_size);
+       unsigned bv_seg_lim = PAGE_SIZE;
+
+       if (lim->max_segment_size < UINT_MAX)
+               bv_seg_lim = lim->max_segment_size;

         bio_for_each_bvec(bv, bio, iter) {
                 /*

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich

Re: [PATCH 3/6] blk-merge: split bio by max_segment_size, not PAGE_SIZE

[Hannes Reinecke]

On 5/15/24 14:29, Hannes Reinecke wrote:
> On 5/15/24 02:20, John Garry wrote:
>> On 14/05/2024 11:38, Hannes Reinecke wrote:
>>> Bvecs can be larger than a page, and the block layer handles
>>> this just fine. So do not split by PAGE_SIZE but rather by
>>> the max_segment_size if that happens to be larger.
>> Can you check scsi_debug for this series? I took this series only up 
>> to this change, and got:
>>
>>      Startin[    1.736470] ------------[ cut here ]------------
>> g Load [    1.737777] WARNING: CPU: 0 PID: 52 at block/blk-merge.c:581 
>> __blk_rq_map_sg+0x46a/0x480
>> Kernel Module fu[    1.738862] Modules linked in:
>> se...[    1.739370] CPU: 0 PID: 52 Comm: kworker/0:1H Not tainted 
>> 6.9.0-00002-g4eaa50af9312-dirty #2416
>>
>> [    1.740474] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), 
>> BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
>> [    1.741809] Workqueue: kblockd blk_mq_run_work_fn
>> [    1.742379] RIP: 0010:__blk_rq_map_sg+0x46a/0x480
>> [    1.742939] Code: 17 fe ff ff 44 89 58 0c 48 8b 01 e9 ec fc ff ff 
>> 43 8d 3c 06 48 8b 14 24 81 ff 00 10 00 00 0f 86 af fc ff ff e9 02 f0
>> [    1.743015] systemd[1]: File System Check on Root Device was 
>> skipped because of a failed condition check (ConditionPathIsReadWrite=!/.
>> [    1.745122] RSP: 0018:ff37636e4032bb90 EFLAGS: 00010212
>> [    1.746419] systemd[1]: systemd-journald.service: unit configures 
>> an IP firewall, but the local system does not support BPF/cgroup fi.
>> [    1.746891] RAX: 000000000000001c RBX: 00000000000001b0 RCX: 
>> ff28e6d8b0950a00
>> [    1.747903] systemd[1]: (This warning is only shown for the first 
>> unit using IP firewalling.)
>> [    1.748549] RDX: ff7662becb4ac482 RSI: 0000000000001000 RDI: 
>> 00000000fffffffd
>> [    1.749688] systemd[1]: Starting Journal Service...
>> [    1.749895] RBP: ff7662becb4abf80 R08: 0000000000000000 R09: 
>> ff28e6d880fadd40
>> [    1.750965] R10: ff7662becb4ac480 R11: 0000000000000000 R12: 
>> 0000000000000000
>> [    1.750966] R13: 0000000000000002 R14: 0000000000001000 R15: 
>> ff7662becb4ac480
>> [    1.750970] FS:  0000000000000000(0000) GS:ff28e6da75c00000(0000) 
>> knlGS:0000000000000000
>> [    1.750972] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [    1.750973] CR2: 00007f7407f19000 CR3: 0000000100f24002 CR4: 
>> 0000000000771ef0
>> [    1.750974] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 
>> 0000000000000000
>> [    1.750975] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 
>> 0000000000000400
>> [    1.750976] PKRU: 55555554
>> [    1.750977] Call Trace:
>> [    1.750984]  <TASK>
>> [    1.750986]  ? __warn+0x7e/0x130
>> [    1.750992]  ? __blk_rq_map_sg+0x46a/0x480
>> [    1.750994]  ? report_bug+0x18e/0x1a0
>> [    1.750999]  ? handle_bug+0x3d/0x70
>> [    1.751003]  ? exc_invalid_op+0x18/0x70
>> [    1.751006]  ? asm_exc_invalid_op+0x1a/0x20
>> [    1.751009]  ? __blk_rq_map_sg+0x46a/0x480
>> [    1.751012]  scsi_alloc_sgtables+0xb7/0x3f0
>> [    1.751019]  sd_init_command+0x177/0x9d0
>> [    1.751023]  scsi_queue_rq+0x7c1/0xae0
>> [    1.751027]  blk_mq_dispatch_rq_list+0x2bc/0x7c0
>> [    1.751031]  __blk_mq_sched_dispatch_requests+0x409/0x5c0
>> [    1.751035]  blk_mq_sched_dispatch_requests+0x2c/0x60
>> [    1.751037]  blk_mq_run_work_fn+0x5f/0x70
>> [    1.751039]  process_one_work+0x149/0x360
>>
>> I suspect that you would need to also change the PAGE_SIZE check in 
>> __blk_bios_map_sg() also. However, I am not confident that the change 
>> below is ok to begin with...
>>
>> BTW, scsi_debug does use an insane max_segment_size of -1
>>
> Can you try with this patch?
> 
> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 570573d7a34f..5da63180069e 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -278,7 +278,10 @@ struct bio *bio_split_rw(struct bio *bio, const 
> struct queue_limits *lim,
>          struct bio_vec bv, bvprv, *bvprvp = NULL;
>          struct bvec_iter iter;
>          unsigned nsegs = 0, bytes = 0;
> -       unsigned bv_seg_lim = max(PAGE_SIZE, lim->max_segment_size);
> +       unsigned bv_seg_lim = PAGE_SIZE;
> +
> +       if (lim->max_segment_size < UINT_MAX)
> +               bv_seg_lim = lim->max_segment_size;
> 
>          bio_for_each_bvec(bv, bio, iter) {
>                  /*
> 
Hmm. No, forget it. Working on another fix.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich

Re: [PATCH 3/6] blk-merge: split bio by max_segment_size, not PAGE_SIZE

[John Garry]

On 15/05/2024 06:29, Hannes Reinecke wrote:
>>
>> I suspect that you would need to also change the PAGE_SIZE check in 
>> __blk_bios_map_sg() also. However, I am not confident that the change 
>> below is ok to begin with...
>>
>> BTW, scsi_debug does use an insane max_segment_size of -1
>>
> Can you try with this patch?

It's scsi_debug, anyone can try it.

As for Luis' original issue, I did not see a proper explanation why the 
crash occurred. The splitting code should consider max segment size 
already, AFAICS. We seem to be slicing off less than LBS, which means 
bytes = 0 after the rounddown, which crashes. why?

I think that all request_queue limits should really be double-checked 
for this LBS on NVMe. The virtual_boundary_mask is still 4K, which 
should be ok.