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Commit 2ff1fa67 authored by Pierre Ossman's avatar Pierre Ossman
Browse files

mmc_block: bounce buffer highmem support 



Support highmem pages in the bounce buffer code by using the
sg_copy_from/to_buffer() functions.

Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
parent 719a61b4

drivers/mmc/card/queue.c

+31 −66
Original line number Diff line number Diff line
@@ -148,7 +148,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock 
			printk(KERN_WARNING "%s: unable to allocate "

				"bounce buffer\n", mmc_card_name(card));

		} else {

			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_HIGH);

			blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);

			blk_queue_max_sectors(mq->queue, bouncesz / 512);

			blk_queue_max_phys_segments(mq->queue, bouncesz / 512);

			blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
@@ -290,55 +290,15 @@ void mmc_queue_resume(struct mmc_queue *mq) 
	}

}



static void copy_sg(struct scatterlist *dst, unsigned int dst_len,

	struct scatterlist *src, unsigned int src_len)

{

	unsigned int chunk;

	char *dst_buf, *src_buf;

	unsigned int dst_size, src_size;



	dst_buf = NULL;

	src_buf = NULL;

	dst_size = 0;

	src_size = 0;



	while (src_len) {

		BUG_ON(dst_len == 0);



		if (dst_size == 0) {

			dst_buf = sg_virt(dst);

			dst_size = dst->length;

		}



		if (src_size == 0) {

			src_buf = sg_virt(src);

			src_size = src->length;

		}



		chunk = min(dst_size, src_size);



		memcpy(dst_buf, src_buf, chunk);



		dst_buf += chunk;

		src_buf += chunk;

		dst_size -= chunk;

		src_size -= chunk;



		if (dst_size == 0) {

			dst++;

			dst_len--;

		}



		if (src_size == 0) {

			src++;

			src_len--;

		}

	}

}



/*

 * Prepare the sg list(s) to be handed of to the host driver

 */

unsigned int mmc_queue_map_sg(struct mmc_queue *mq)

{

	unsigned int sg_len;

	size_t buflen;

	struct scatterlist *sg;

	int i;



	if (!mq->bounce_buf)

		return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
@@ -349,47 +309,52 @@ unsigned int mmc_queue_map_sg(struct mmc_queue *mq) 


	mq->bounce_sg_len = sg_len;



	/*

	 * Shortcut in the event we only get a single entry.

	 */

	if (sg_len == 1) {

		memcpy(mq->sg, mq->bounce_sg, sizeof(struct scatterlist));

		return 1;

	}

	buflen = 0;

	for_each_sg(mq->bounce_sg, sg, sg_len, i)

		buflen += sg->length;



	sg_init_one(mq->sg, mq->bounce_buf, 0);



	while (sg_len) {

		mq->sg[0].length += mq->bounce_sg[sg_len - 1].length;

		sg_len--;

	}

	sg_init_one(mq->sg, mq->bounce_buf, buflen);



	return 1;

}



/*

 * If writing, bounce the data to the buffer before the request

 * is sent to the host driver

 */

void mmc_queue_bounce_pre(struct mmc_queue *mq)

{

	unsigned long flags;



	if (!mq->bounce_buf)

		return;



	if (mq->bounce_sg_len == 1)

		return;

	if (rq_data_dir(mq->req) != WRITE)

		return;



	copy_sg(mq->sg, 1, mq->bounce_sg, mq->bounce_sg_len);

	local_irq_save(flags);

	sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,

		mq->bounce_buf, mq->sg[0].length);

	local_irq_restore(flags);

}



/*

 * If reading, bounce the data from the buffer after the request

 * has been handled by the host driver

 */

void mmc_queue_bounce_post(struct mmc_queue *mq)

{

	unsigned long flags;



	if (!mq->bounce_buf)

		return;



	if (mq->bounce_sg_len == 1)

		return;

	if (rq_data_dir(mq->req) != READ)

		return;



	copy_sg(mq->bounce_sg, mq->bounce_sg_len, mq->sg, 1);

	local_irq_save(flags);

	sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,

		mq->bounce_buf, mq->sg[0].length);

	local_irq_restore(flags);

}