Commit 386ecb12 authored by Dave Gordon's avatar Dave Gordon Committed by Linus Torvalds
Browse files

drivers/scsi/scsi_debug.c: resolve sg buffer const-ness issue 



do_device_access() takes a separate parameter to indicate the direction of
data transfer, which it used to use to select the appropriate function out
of sg_pcopy_{to,from}_buffer().  However these two functions now have

So this patch makes it bypass these wrappers and call the underlying
function sg_copy_buffer() directly; this has the same calling style as
do_device_access() i.e.  a separate direction-of-transfer parameter and no
pointers-to-const, so skipping the wrappers not only eliminates the
warning, it also make the code simpler :)

[akpm@linux-foundation.org: fix very broken build]
Signed-off-by: default avatarDave Gordon <david.s.gordon@intel.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2a1bf8f9

drivers/scsi/scsi_debug.c

+4 −8
Original line number Diff line number Diff line
@@ -2363,17 +2363,13 @@ do_device_access(struct scsi_cmnd *scmd, u64 lba, u32 num, bool do_write) 
	u64 block, rest = 0;

	struct scsi_data_buffer *sdb;

	enum dma_data_direction dir;

	size_t (*func)(struct scatterlist *, unsigned int, void *, size_t,

		       off_t);



	if (do_write) {

		sdb = scsi_out(scmd);

		dir = DMA_TO_DEVICE;

		func = sg_pcopy_to_buffer;

	} else {

		sdb = scsi_in(scmd);

		dir = DMA_FROM_DEVICE;

		func = sg_pcopy_from_buffer;

	}



	if (!sdb->length)
@@ -2385,16 +2381,16 @@ do_device_access(struct scsi_cmnd *scmd, u64 lba, u32 num, bool do_write) 
	if (block + num > sdebug_store_sectors)

		rest = block + num - sdebug_store_sectors;



	ret = func(sdb->table.sgl, sdb->table.nents,

	ret = sg_copy_buffer(sdb->table.sgl, sdb->table.nents,

		   fake_storep + (block * scsi_debug_sector_size),

		   (num - rest) * scsi_debug_sector_size, 0);

		   (num - rest) * scsi_debug_sector_size, 0, do_write);

	if (ret != (num - rest) * scsi_debug_sector_size)

		return ret;



	if (rest) {

		ret += func(sdb->table.sgl, sdb->table.nents,

		ret += sg_copy_buffer(sdb->table.sgl, sdb->table.nents,

			    fake_storep, rest * scsi_debug_sector_size,

			    (num - rest) * scsi_debug_sector_size);

			    (num - rest) * scsi_debug_sector_size, do_write);

	}



	return ret;

include/linux/scatterlist.h

+3 −0
Original line number Diff line number Diff line
@@ -265,6 +265,9 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, 
	unsigned long offset, unsigned long size,

	gfp_t gfp_mask);



size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,

		      size_t buflen, off_t skip, bool to_buffer);



size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,

			   const void *buf, size_t buflen);

size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,

lib/scatterlist.c

+3 −3
Original line number Diff line number Diff line
@@ -650,9 +650,8 @@ EXPORT_SYMBOL(sg_miter_stop); 
 * Returns the number of copied bytes.

 *

 **/

static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,

			     void *buf, size_t buflen, off_t skip,

			     bool to_buffer)

size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,

		      size_t buflen, off_t skip, bool to_buffer)

{

	unsigned int offset = 0;

	struct sg_mapping_iter miter;
@@ -689,6 +688,7 @@ static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, 
	local_irq_restore(flags);

	return offset;

}

EXPORT_SYMBOL(sg_copy_buffer);



/**

 * sg_copy_from_buffer - Copy from a linear buffer to an SG list

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