diff mbox series

[5/5] brd: make logical sector size configurable

Message ID 20230306120127.21375-6-hare@suse.de (mailing list archive)
State New, archived
Headers show
Series brd: Allow to change block sizes | expand

Commit Message

Hannes Reinecke March 6, 2023, 12:01 p.m. UTC 
Add a module option 'rd_logical_blksize' to allow the user to change
the logical sector size of the RAM disks.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/brd.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

Comments

Pankaj Raghav March 7, 2023, 9:01 a.m. UTC | #1 
> @@ -57,7 +59,7 @@ static struct folio *brd_lookup_folio(struct brd_device *brd, sector_t sector)
>  {
>  	pgoff_t idx;
>  	struct folio *folio;
> -	unsigned int rd_sector_shift = brd->brd_sector_shift - SECTOR_SHIFT;
> +	unsigned int rd_sector_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;

Could we create a simple macro instead of repeating this everywhere?
#define RD_SECTOR_SHIFT(brd) (brd->brd_sector_shift - brd->brd_logical_sector_shift) 

>  
>  	/*
>  	 * The folio lifetime is protected by the fact that we have opened the
>  			bio_io_error(bio);
>  			return;
>  		}
> -		sector += len >> SECTOR_SHIFT;
> +		sector += len >> brd->brd_logical_sector_shift;
>  	}
>  
>  	bio_endio(bio);
> @@ -353,6 +355,10 @@ static unsigned int rd_blksize = PAGE_SIZE;
>  module_param(rd_blksize, uint, 0444);
>  MODULE_PARM_DESC(rd_blksize, "Blocksize of each RAM disk in bytes.");
>  
> +static unsigned int rd_logical_blksize = SECTOR_SIZE;
> +module_param(rd_logical_blksize, uint, 0444);
> +MODULE_PARM_DESC(rd_logical_blksize, "Logical blocksize of each RAM disk in bytes.");
> +
>  MODULE_LICENSE("GPL");
>  MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
>  MODULE_ALIAS("rd");
> @@ -391,6 +397,8 @@ static int brd_alloc(int i)
>  	list_add_tail(&brd->brd_list, &brd_devices);
>  	brd->brd_sector_shift = ilog2(rd_blksize);
>  	brd->brd_sector_size = rd_blksize;
> +	brd->brd_logical_sector_shift = ilog2(rd_logical_blksize);
> +	brd->brd_logical_sector_size = rd_logical_blksize;

We should a check here to see if logical block > rd_blksize similar
to what is done in blk_queue_logical_block_size()?

// physical block size should not be less than the logical block size
if (rd_blksize < rd_logical_blksize) {
	brd->brd_logical_sector_shift = ilog2(rd_blksize);
	brd->brd_logical_sector_size = rd_blksize;
 }

>  
>  	spin_lock_init(&brd->brd_lock);
>  	INIT_RADIX_TREE(&brd->brd_folios, GFP_ATOMIC);
> @@ -418,6 +426,7 @@ static int brd_alloc(int i)
>  		goto out_cleanup_disk;
>  	}
>  	blk_queue_physical_block_size(disk->queue, rd_blksize);
> +	blk_queue_logical_block_size(disk->queue, rd_logical_blksize);
>  	blk_queue_max_hw_sectors(disk->queue, RD_MAX_SECTOR_SIZE);
>  
>  	/* Tell the block layer that this is not a rotational device */
> -- 
> 2.35.3
>
Hannes Reinecke March 7, 2023, 11:06 a.m. UTC | #2 
On 3/7/23 10:01, Pankaj Raghav wrote:
>> @@ -57,7 +59,7 @@ static struct folio *brd_lookup_folio(struct brd_device *brd, sector_t sector)
>>   {
>>   	pgoff_t idx;
>>   	struct folio *folio;
>> -	unsigned int rd_sector_shift = brd->brd_sector_shift - SECTOR_SHIFT;
>> +	unsigned int rd_sector_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;
> 
> Could we create a simple macro instead of repeating this everywhere?
> #define RD_SECTOR_SHIFT(brd) (brd->brd_sector_shift - brd->brd_logical_sector_shift)
> 
Yeah, I'm not utterly happy with that one, too; this patchset is 
primarily a mechanical conversion to avoid errors.
Will be changing it.

>>   
>>   	/*
>>   	 * The folio lifetime is protected by the fact that we have opened the
>>   			bio_io_error(bio);
>>   			return;
>>   		}
>> -		sector += len >> SECTOR_SHIFT;
>> +		sector += len >> brd->brd_logical_sector_shift;
>>   	}
>>   
>>   	bio_endio(bio);
>> @@ -353,6 +355,10 @@ static unsigned int rd_blksize = PAGE_SIZE;
>>   module_param(rd_blksize, uint, 0444);
>>   MODULE_PARM_DESC(rd_blksize, "Blocksize of each RAM disk in bytes.");
>>   
>> +static unsigned int rd_logical_blksize = SECTOR_SIZE;
>> +module_param(rd_logical_blksize, uint, 0444);
>> +MODULE_PARM_DESC(rd_logical_blksize, "Logical blocksize of each RAM disk in bytes.");
>> +
>>   MODULE_LICENSE("GPL");
>>   MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
>>   MODULE_ALIAS("rd");
>> @@ -391,6 +397,8 @@ static int brd_alloc(int i)
>>   	list_add_tail(&brd->brd_list, &brd_devices);
>>   	brd->brd_sector_shift = ilog2(rd_blksize);
>>   	brd->brd_sector_size = rd_blksize;
>> +	brd->brd_logical_sector_shift = ilog2(rd_logical_blksize);
>> +	brd->brd_logical_sector_size = rd_logical_blksize;
> 
> We should a check here to see if logical block > rd_blksize similar
> to what is done in blk_queue_logical_block_size()?
>  > // physical block size should not be less than the logical block size
> if (rd_blksize < rd_logical_blksize) {
> 	brd->brd_logical_sector_shift = ilog2(rd_blksize);
> 	brd->brd_logical_sector_size = rd_blksize;
>   }
> 
Sure. Keith already complained about it.

Cheers,

Hannes
Pankaj Raghav May 17, 2023, 9:31 a.m. UTC | #3 
Hi Hannes,

> @@ -309,8 +311,8 @@ static void brd_submit_bio(struct bio *bio)
>  		int err;
I think you missed the conversion from "kernel" logical sectors to the
device logical sector here:
sector_t sector = bio->bi_iter.bi_sector >> 
                 (brd->brd_logical_sector_shift - SECTOR_SHIFT);

This fixes the issue when you try to do a fio with -verify on a 4k
logical and physical block size.
>  
>  		/* Don't support un-aligned buffer */
> -		WARN_ON_ONCE((iter.offset & (SECTOR_SIZE - 1)) ||
> -				(len & (SECTOR_SIZE - 1)));
> +		WARN_ON_ONCE((iter.offset & (brd->brd_logical_sector_size - 1)) ||
> +				(len & (brd->brd_logical_sector_size - 1)));
>  
>  		err = brd_do_folio(brd, iter.folio, len, iter.offset,
>  				   bio->bi_opf, sector);
> @@ -322,7 +324,7 @@ static void brd_submit_bio(struct bio *bio)
>  			bio_io_error(bio);
>  			return;
>  		}
> -		sector += len >> SECTOR_SHIFT;
> +		sector += len >> brd->brd_logical_sector_shift;
As you can see here, you divide the len with device logical block size
to go to the next sector.
>  	}
>  
>  	bio_endio(bio);
diff mbox series

Patch

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 1ed114cd5cb0..dda791805aba 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -48,6 +48,8 @@  struct brd_device {
 	u64			brd_nr_folios;
 	unsigned int		brd_sector_shift;
 	unsigned int		brd_sector_size;
+	unsigned int		brd_logical_sector_shift;
+	unsigned int		brd_logical_sector_size;
 };
 
 /*
@@ -57,7 +59,7 @@  static struct folio *brd_lookup_folio(struct brd_device *brd, sector_t sector)
 {
 	pgoff_t idx;
 	struct folio *folio;
-	unsigned int rd_sector_shift = brd->brd_sector_shift - SECTOR_SHIFT;
+	unsigned int rd_sector_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;
 
 	/*
 	 * The folio lifetime is protected by the fact that we have opened the
@@ -87,7 +89,7 @@  static int brd_insert_folio(struct brd_device *brd, sector_t sector, gfp_t gfp)
 {
 	pgoff_t idx;
 	struct folio *folio;
-	unsigned int rd_sector_shift = brd->brd_sector_shift - SECTOR_SHIFT;
+	unsigned int rd_sector_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;
 	unsigned int rd_sector_order = get_order(brd->brd_sector_size);
 	int ret = 0;
 
@@ -172,10 +174,10 @@  static void brd_free_folios(struct brd_device *brd)
 static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n,
 			     gfp_t gfp)
 {
-	unsigned int rd_sectors_shift = brd->brd_sector_shift - SECTOR_SHIFT;
+	unsigned int rd_sectors_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;
 	unsigned int rd_sectors = 1 << rd_sectors_shift;
 	unsigned int rd_sector_size = brd->brd_sector_size;
-	unsigned int offset = (sector & (rd_sectors - 1)) << SECTOR_SHIFT;
+	unsigned int offset = (sector & (rd_sectors - 1)) << brd->brd_logical_sector_shift;
 	size_t copy;
 	int ret;
 
@@ -184,7 +186,7 @@  static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n,
 	if (ret)
 		return ret;
 	if (copy < n) {
-		sector += copy >> SECTOR_SHIFT;
+		sector += copy >> brd->brd_logical_sector_shift;
 		ret = brd_insert_folio(brd, sector, gfp);
 	}
 	return ret;
@@ -198,10 +200,10 @@  static void copy_to_brd(struct brd_device *brd, const void *src,
 {
 	struct folio *folio;
 	void *dst;
-	unsigned int rd_sectors_shift = brd->brd_sector_shift - SECTOR_SHIFT;
+	unsigned int rd_sectors_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;
 	unsigned int rd_sectors = 1 << rd_sectors_shift;
 	unsigned int rd_sector_size = brd->brd_sector_size;
-	unsigned int offset = (sector & (rd_sectors - 1)) << SECTOR_SHIFT;
+	unsigned int offset = (sector & (rd_sectors - 1)) << brd->brd_logical_sector_shift;
 	size_t copy;
 
 	copy = min_t(size_t, n, rd_sector_size - offset);
@@ -214,7 +216,7 @@  static void copy_to_brd(struct brd_device *brd, const void *src,
 
 	if (copy < n) {
 		src += copy;
-		sector += copy >> SECTOR_SHIFT;
+		sector += copy >> brd->brd_logical_sector_shift;
 		copy = n - copy;
 		folio = brd_lookup_folio(brd, sector);
 		BUG_ON(!folio);
@@ -233,10 +235,10 @@  static void copy_from_brd(void *dst, struct brd_device *brd,
 {
 	struct folio *folio;
 	void *src;
-	unsigned int rd_sectors_shift = brd->brd_sector_shift - SECTOR_SHIFT;
+	unsigned int rd_sectors_shift = brd->brd_sector_shift - brd->brd_logical_sector_shift;
 	unsigned int rd_sectors = 1 << rd_sectors_shift;
 	unsigned int rd_sector_size = brd->brd_sector_size;
-	unsigned int offset = (sector & (rd_sectors - 1)) << SECTOR_SHIFT;
+	unsigned int offset = (sector & (rd_sectors - 1)) << brd->brd_logical_sector_shift;
 	size_t copy;
 
 	copy = min_t(size_t, n, rd_sector_size - offset);
@@ -250,7 +252,7 @@  static void copy_from_brd(void *dst, struct brd_device *brd,
 
 	if (copy < n) {
 		dst += copy;
-		sector += copy >> SECTOR_SHIFT;
+		sector += copy >> brd->brd_logical_sector_shift;
 		copy = n - copy;
 		folio = brd_lookup_folio(brd, sector);
 		if (folio) {
@@ -309,8 +311,8 @@  static void brd_submit_bio(struct bio *bio)
 		int err;
 
 		/* Don't support un-aligned buffer */
-		WARN_ON_ONCE((iter.offset & (SECTOR_SIZE - 1)) ||
-				(len & (SECTOR_SIZE - 1)));
+		WARN_ON_ONCE((iter.offset & (brd->brd_logical_sector_size - 1)) ||
+				(len & (brd->brd_logical_sector_size - 1)));
 
 		err = brd_do_folio(brd, iter.folio, len, iter.offset,
 				   bio->bi_opf, sector);
@@ -322,7 +324,7 @@  static void brd_submit_bio(struct bio *bio)
 			bio_io_error(bio);
 			return;
 		}
-		sector += len >> SECTOR_SHIFT;
+		sector += len >> brd->brd_logical_sector_shift;
 	}
 
 	bio_endio(bio);
@@ -353,6 +355,10 @@  static unsigned int rd_blksize = PAGE_SIZE;
 module_param(rd_blksize, uint, 0444);
 MODULE_PARM_DESC(rd_blksize, "Blocksize of each RAM disk in bytes.");
 
+static unsigned int rd_logical_blksize = SECTOR_SIZE;
+module_param(rd_logical_blksize, uint, 0444);
+MODULE_PARM_DESC(rd_logical_blksize, "Logical blocksize of each RAM disk in bytes.");
+
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_BLOCKDEV_MAJOR(RAMDISK_MAJOR);
 MODULE_ALIAS("rd");
@@ -391,6 +397,8 @@  static int brd_alloc(int i)
 	list_add_tail(&brd->brd_list, &brd_devices);
 	brd->brd_sector_shift = ilog2(rd_blksize);
 	brd->brd_sector_size = rd_blksize;
+	brd->brd_logical_sector_shift = ilog2(rd_logical_blksize);
+	brd->brd_logical_sector_size = rd_logical_blksize;
 
 	spin_lock_init(&brd->brd_lock);
 	INIT_RADIX_TREE(&brd->brd_folios, GFP_ATOMIC);
@@ -418,6 +426,7 @@  static int brd_alloc(int i)
 		goto out_cleanup_disk;
 	}
 	blk_queue_physical_block_size(disk->queue, rd_blksize);
+	blk_queue_logical_block_size(disk->queue, rd_logical_blksize);
 	blk_queue_max_hw_sectors(disk->queue, RD_MAX_SECTOR_SIZE);
 
 	/* Tell the block layer that this is not a rotational device */