async_tx: add sum check flags

Replace the flat zero_sum_result with a collection of flags to contain
the P (xor) zero-sum result, and the soon to be utilized Q (raid6 reed
solomon syndrome) zero-sum result.  Use the SUM_CHECK_ namespace instead
of DMA_ since these flags will be used on non-dma-zero-sum enabled
platforms.
Reviewed-by: NAndre Noll <maan@systemlinux.org>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

arch/arm/include/asm/hardware/iop3xx-adma.h

@@ -756,13 +756,14 @@ static inline void iop_desc_set_block_fill_val(struct iop_adma_desc_slot *desc,
 	hw_desc->src[0] = val;
 }
 
-static inline int iop_desc_get_zero_result(struct iop_adma_desc_slot *desc)
+static inline enum sum_check_flags
+iop_desc_get_zero_result(struct iop_adma_desc_slot *desc)
 {
 	struct iop3xx_desc_aau *hw_desc = desc->hw_desc;
 	struct iop3xx_aau_desc_ctrl desc_ctrl = hw_desc->desc_ctrl_field;
 
 	iop_paranoia(!(desc_ctrl.tx_complete && desc_ctrl.zero_result_en));
-	return desc_ctrl.zero_result_err;
+	return desc_ctrl.zero_result_err << SUM_CHECK_P;
 }
 
 static inline void iop_chan_append(struct iop_adma_chan *chan)

arch/arm/mach-iop13xx/include/mach/adma.h

@@ -428,18 +428,20 @@ static inline void iop_desc_set_block_fill_val(struct iop_adma_desc_slot *desc,
 	hw_desc->block_fill_data = val;
 }
 
-static inline int iop_desc_get_zero_result(struct iop_adma_desc_slot *desc)
+static inline enum sum_check_flags
+iop_desc_get_zero_result(struct iop_adma_desc_slot *desc)
 {
 	struct iop13xx_adma_desc_hw *hw_desc = desc->hw_desc;
 	struct iop13xx_adma_desc_ctrl desc_ctrl = hw_desc->desc_ctrl_field;
 	struct iop13xx_adma_byte_count byte_count = hw_desc->byte_count_field;
+	enum sum_check_flags flags;
 
 	BUG_ON(!(byte_count.tx_complete && desc_ctrl.zero_result));
 
-	if (desc_ctrl.pq_xfer_en)
-		return byte_count.zero_result_err_q;
-	else
-		return byte_count.zero_result_err;
+	flags = byte_count.zero_result_err_q << SUM_CHECK_Q;
+	flags |= byte_count.zero_result_err << SUM_CHECK_P;
+
+	return flags;
 }
 
 static inline void iop_chan_append(struct iop_adma_chan *chan)

crypto/async_tx/async_xor.c

@@ -246,7 +246,7 @@ static int page_is_zero(struct page *p, unsigned int offset, size_t len)
  */
 struct dma_async_tx_descriptor *
 async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
-	      int src_cnt, size_t len, u32 *result,
+	      int src_cnt, size_t len, enum sum_check_flags *result,
 	      struct async_submit_ctl *submit)
 {
 	struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR_VAL,
@@ -304,7 +304,7 @@ async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
 
 		async_tx_quiesce(&tx);
 
-		*result = page_is_zero(dest, offset, len) ? 0 : 1;
+		*result = !page_is_zero(dest, offset, len) << SUM_CHECK_P;
 
 		async_tx_sync_epilog(submit);
 		submit->flags = flags_orig;

drivers/md/raid5.c

@@ -2590,7 +2590,7 @@ static void handle_parity_checks5(raid5_conf_t *conf, struct stripe_head *sh,
 		 * we are done.  Otherwise update the mismatch count and repair
 		 * parity if !MD_RECOVERY_CHECK
 		 */
-		if (sh->ops.zero_sum_result == 0)
+		if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
 			/* parity is correct (on disc,
 			 * not in buffer any more)
 			 */

drivers/md/raid5.h

@@ -2,6 +2,7 @@
 #define _RAID5_H
 
 #include <linux/raid/xor.h>
+#include <linux/dmaengine.h>
 
 /*
  *
@@ -216,7 +217,7 @@ struct stripe_head {
 	 */
 	struct stripe_operations {
 		int		     target;
-		u32		   zero_sum_result;
+		enum sum_check_flags zero_sum_result;
 	} ops;
 	struct r5dev {
 		struct bio	req;

include/linux/async_tx.h

@@ -148,7 +148,7 @@ async_xor(struct page *dest, struct page **src_list, unsigned int offset,
 
 struct dma_async_tx_descriptor *
 async_xor_val(struct page *dest, struct page **src_list, unsigned int offset,
-	      int src_cnt, size_t len, u32 *result,
+	      int src_cnt, size_t len, enum sum_check_flags *result,
 	      struct async_submit_ctl *submit);
 
 struct dma_async_tx_descriptor *

include/linux/dmaengine.h

@@ -86,6 +86,25 @@ enum dma_ctrl_flags {
 	DMA_COMPL_SKIP_DEST_UNMAP = (1 << 3),
 };
 
+/**
+ * enum sum_check_bits - bit position of pq_check_flags
+ */
+enum sum_check_bits {
+	SUM_CHECK_P = 0,
+	SUM_CHECK_Q = 1,
+};
+
+/**
+ * enum pq_check_flags - result of async_{xor,pq}_zero_sum operations
+ * @SUM_CHECK_P_RESULT - 1 if xor zero sum error, 0 otherwise
+ * @SUM_CHECK_Q_RESULT - 1 if reed-solomon zero sum error, 0 otherwise
+ */
+enum sum_check_flags {
+	SUM_CHECK_P_RESULT = (1 << SUM_CHECK_P),
+	SUM_CHECK_Q_RESULT = (1 << SUM_CHECK_Q),
+};
+
+
 /**
  * dma_cap_mask_t - capabilities bitmap modeled after cpumask_t.
  * See linux/cpumask.h
@@ -245,7 +264,7 @@ struct dma_device {
 		unsigned int src_cnt, size_t len, unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_xor_val)(
 		struct dma_chan *chan, dma_addr_t *src,	unsigned int src_cnt,
-		size_t len, u32 *result, unsigned long flags);
+		size_t len, enum sum_check_flags *result, unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
 		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
 		unsigned long flags);