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Commit aaced993 authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by James Bottomley
Browse files

scsi: storvsc: Don't assume that the scatterlist is not chained 



The current code assumes that the scatterlists presented are not chained.
Fix the code to not make this assumption.

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: default avatarLong Li <longli@microsoft.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Odin.com>
parent 8de58074

drivers/scsi/storvsc_drv.c

+57 −42
Original line number Diff line number Diff line
@@ -626,19 +626,6 @@ static struct scatterlist *create_bounce_buffer(struct scatterlist *sgl, 
	return NULL;

}



/* Disgusting wrapper functions */

static inline unsigned long sg_kmap_atomic(struct scatterlist *sgl, int idx)

{

	void *addr = kmap_atomic(sg_page(sgl + idx));

	return (unsigned long)addr;

}



static inline void sg_kunmap_atomic(unsigned long addr)

{

	kunmap_atomic((void *)addr);

}





/* Assume the original sgl has enough room */

static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl,

					    struct scatterlist *bounce_sgl,
@@ -653,32 +640,38 @@ static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl, 
	unsigned long bounce_addr = 0;

	unsigned long dest_addr = 0;

	unsigned long flags;

	struct scatterlist *cur_dest_sgl;

	struct scatterlist *cur_src_sgl;



	local_irq_save(flags);



	cur_dest_sgl = orig_sgl;

	cur_src_sgl = bounce_sgl;

	for (i = 0; i < orig_sgl_count; i++) {

		dest_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;

		dest_addr = (unsigned long)

				kmap_atomic(sg_page(cur_dest_sgl)) +

				cur_dest_sgl->offset;

		dest = dest_addr;

		destlen = orig_sgl[i].length;

		destlen = cur_dest_sgl->length;



		if (bounce_addr == 0)

			bounce_addr = sg_kmap_atomic(bounce_sgl,j);

			bounce_addr = (unsigned long)kmap_atomic(

							sg_page(cur_src_sgl));



		while (destlen) {

			src = bounce_addr + bounce_sgl[j].offset;

			srclen = bounce_sgl[j].length - bounce_sgl[j].offset;

			src = bounce_addr + cur_src_sgl->offset;

			srclen = cur_src_sgl->length - cur_src_sgl->offset;



			copylen = min(srclen, destlen);

			memcpy((void *)dest, (void *)src, copylen);



			total_copied += copylen;

			bounce_sgl[j].offset += copylen;

			cur_src_sgl->offset += copylen;

			destlen -= copylen;

			dest += copylen;



			if (bounce_sgl[j].offset == bounce_sgl[j].length) {

			if (cur_src_sgl->offset == cur_src_sgl->length) {

				/* full */

				sg_kunmap_atomic(bounce_addr);

				kunmap_atomic((void *)bounce_addr);

				j++;



				/*
@@ -692,21 +685,27 @@ static unsigned int copy_from_bounce_buffer(struct scatterlist *orig_sgl, 
					/*

					 * We are done; cleanup and return.

					 */

					sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);

					kunmap_atomic((void *)(dest_addr -

						cur_dest_sgl->offset));

					local_irq_restore(flags);

					return total_copied;

				}



				/* if we need to use another bounce buffer */

				if (destlen || i != orig_sgl_count - 1)

					bounce_addr = sg_kmap_atomic(bounce_sgl,j);

				if (destlen || i != orig_sgl_count - 1) {

					cur_src_sgl = sg_next(cur_src_sgl);

					bounce_addr = (unsigned long)

							kmap_atomic(

							sg_page(cur_src_sgl));

				}

			} else if (destlen == 0 && i == orig_sgl_count - 1) {

				/* unmap the last bounce that is < PAGE_SIZE */

				sg_kunmap_atomic(bounce_addr);

				kunmap_atomic((void *)bounce_addr);

			}

		}



		sg_kunmap_atomic(dest_addr - orig_sgl[i].offset);

		kunmap_atomic((void *)(dest_addr - cur_dest_sgl->offset));

		cur_dest_sgl = sg_next(cur_dest_sgl);

	}



	local_irq_restore(flags);
@@ -727,48 +726,61 @@ static unsigned int copy_to_bounce_buffer(struct scatterlist *orig_sgl, 
	unsigned long bounce_addr = 0;

	unsigned long src_addr = 0;

	unsigned long flags;

	struct scatterlist *cur_src_sgl;

	struct scatterlist *cur_dest_sgl;



	local_irq_save(flags);



	cur_src_sgl = orig_sgl;

	cur_dest_sgl = bounce_sgl;



	for (i = 0; i < orig_sgl_count; i++) {

		src_addr = sg_kmap_atomic(orig_sgl,i) + orig_sgl[i].offset;

		src_addr = (unsigned long)

				kmap_atomic(sg_page(cur_src_sgl)) +

				cur_src_sgl->offset;

		src = src_addr;

		srclen = orig_sgl[i].length;

		srclen = cur_src_sgl->length;



		if (bounce_addr == 0)

			bounce_addr = sg_kmap_atomic(bounce_sgl,j);

			bounce_addr = (unsigned long)

					kmap_atomic(sg_page(cur_dest_sgl));



		while (srclen) {

			/* assume bounce offset always == 0 */

			dest = bounce_addr + bounce_sgl[j].length;

			destlen = PAGE_SIZE - bounce_sgl[j].length;

			dest = bounce_addr + cur_dest_sgl->length;

			destlen = PAGE_SIZE - cur_dest_sgl->length;



			copylen = min(srclen, destlen);

			memcpy((void *)dest, (void *)src, copylen);



			total_copied += copylen;

			bounce_sgl[j].length += copylen;

			cur_dest_sgl->length += copylen;

			srclen -= copylen;

			src += copylen;



			if (bounce_sgl[j].length == PAGE_SIZE) {

			if (cur_dest_sgl->length == PAGE_SIZE) {

				/* full..move to next entry */

				sg_kunmap_atomic(bounce_addr);

				kunmap_atomic((void *)bounce_addr);

				bounce_addr = 0;

				j++;

			}



			/* if we need to use another bounce buffer */

			if (srclen && bounce_addr == 0)

				bounce_addr = sg_kmap_atomic(bounce_sgl, j);

			if (srclen && bounce_addr == 0) {

				cur_dest_sgl = sg_next(cur_dest_sgl);

				bounce_addr = (unsigned long)

						kmap_atomic(

						sg_page(cur_dest_sgl));

			}



		}



		sg_kunmap_atomic(src_addr - orig_sgl[i].offset);

		kunmap_atomic((void *)(src_addr - cur_src_sgl->offset));

		cur_src_sgl = sg_next(cur_src_sgl);

	}



	if (bounce_addr)

		sg_kunmap_atomic(bounce_addr);

		kunmap_atomic((void *)bounce_addr);



	local_irq_restore(flags);
@@ -1536,6 +1548,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) 
	struct scatterlist *sgl;

	unsigned int sg_count = 0;

	struct vmscsi_request *vm_srb;

	struct scatterlist *cur_sgl;



	if (vmstor_current_major <= VMSTOR_WIN8_MAJOR) {

		/*
@@ -1617,10 +1630,12 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd) 
		}



		cmd_request->data_buffer.offset = sgl[0].offset;



		for (i = 0; i < sg_count; i++)

		cur_sgl = sgl;

		for (i = 0; i < sg_count; i++) {

			cmd_request->data_buffer.pfn_array[i] =

				page_to_pfn(sg_page((&sgl[i])));

				page_to_pfn(sg_page((cur_sgl)));

			cur_sgl = sg_next(cur_sgl);

		}



	} else if (scsi_sglist(scmnd)) {

		cmd_request->data_buffer.offset =