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Commit 99eb1908 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm switch: factor out switch_region_table_read 



Move code that reads the table to a switch_region_table_read.
It will be needed for the next commit.  No functional change.

Tested-by: default avatarJay Wang <jwang@nimblestorage.com>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent b0246530

drivers/md/dm-switch.c

+13 −5
Original line number Diff line number Diff line
@@ -137,13 +137,23 @@ static void switch_get_position(struct switch_ctx *sctx, unsigned long region_nr 
	*bit *= sctx->region_table_entry_bits;

}



static unsigned switch_region_table_read(struct switch_ctx *sctx, unsigned long region_nr)

{

	unsigned long region_index;

	unsigned bit;



	switch_get_position(sctx, region_nr, &region_index, &bit);



	return (ACCESS_ONCE(sctx->region_table[region_index]) >> bit) &

		((1 << sctx->region_table_entry_bits) - 1);

}



/*

 * Find which path to use at given offset.

 */

static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset)

{

	unsigned long region_index;

	unsigned bit, path_nr;

	unsigned path_nr;

	sector_t p;



	p = offset;
@@ -152,9 +162,7 @@ static unsigned switch_get_path_nr(struct switch_ctx *sctx, sector_t offset) 
	else

		sector_div(p, sctx->region_size);



	switch_get_position(sctx, p, &region_index, &bit);

	path_nr = (ACCESS_ONCE(sctx->region_table[region_index]) >> bit) &

	       ((1 << sctx->region_table_entry_bits) - 1);

	path_nr = switch_region_table_read(sctx, p);



	/* This can only happen if the processor uses non-atomic stores. */

	if (unlikely(path_nr >= sctx->nr_paths))