Commit 01aa26c6 authored by Eric Farman's avatar Eric Farman Committed by Cornelia Huck
Browse files

s390/cio: Combine direct and indirect CCW paths 



With both the direct-addressed and indirect-addressed CCW paths
simplified to this point, the amount of shared code between them is
(hopefully) more easily visible.  Move the processing of IDA-specific
bits into the direct-addressed path, and add some useful commentary of
what the individual pieces are doing.  This allows us to remove the
entire ccwchain_fetch_idal() routine and maintain a single function
for any non-TIC CCW.

Signed-off-by: default avatarEric Farman <farman@linux.ibm.com>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Message-Id: <20190606202831.44135-10-farman@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent e8573b39

drivers/s390/cio/vfio_ccw_cp.c

+39 −76
Original line number Diff line number Diff line
@@ -534,10 +534,12 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, 
{

	struct ccw1 *ccw;

	struct pfn_array *pa;

	u64 iova;

	unsigned long *idaws;

	int ret;

	int bytes = 1;

	int idaw_nr;

	int idaw_nr, idal_len;

	int i;



	ccw = chain->ch_ccw + idx;
@@ -545,7 +547,17 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, 
		bytes = ccw->count;



	/* Calculate size of IDAL */

	idaw_nr = idal_nr_words((void *)(u64)ccw->cda, bytes);

	if (ccw_is_idal(ccw)) {

		/* Read first IDAW to see if it's 4K-aligned or not. */

		/* All subsequent IDAws will be 4K-aligned. */

		ret = copy_from_iova(cp->mdev, &iova, ccw->cda, sizeof(iova));

		if (ret)

			return ret;

	} else {

		iova = ccw->cda;

	}

	idaw_nr = idal_nr_words((void *)iova, bytes);

	idal_len = idaw_nr * sizeof(*idaws);



	/* Allocate an IDAL from host storage */

	idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);
@@ -555,15 +567,36 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, 
	}



	/*

	 * Pin data page(s) in memory.

	 * The number of pages actually is the count of the idaws which will be

	 * needed when translating a direct ccw to a idal ccw.

	 * Allocate an array of pfn's for pages to pin/translate.

	 * The number of pages is actually the count of the idaws

	 * required for the data transfer, since we only only support

	 * 4K IDAWs today.

	 */

	pa = chain->ch_pa + idx;

	ret = pfn_array_alloc(pa, ccw->cda, bytes);

	ret = pfn_array_alloc(pa, iova, bytes);

	if (ret < 0)

		goto out_free_idaws;



	if (ccw_is_idal(ccw)) {

		/* Copy guest IDAL into host IDAL */

		ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idal_len);

		if (ret)

			goto out_unpin;



		/*

		 * Copy guest IDAWs into pfn_array, in case the memory they

		 * occupy is not contiguous.

		 */

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

			pa->pa_iova_pfn[i] = idaws[i] >> PAGE_SHIFT;

	} else {

		/*

		 * No action is required here; the iova addresses in pfn_array

		 * were initialized sequentially in pfn_array_alloc() beginning

		 * with the contents of ccw->cda.

		 */

	}



	if (ccw_does_data_transfer(ccw)) {

		ret = pfn_array_pin(pa, cp->mdev);

		if (ret < 0)
@@ -589,73 +622,6 @@ out_init: 
	return ret;

}



static int ccwchain_fetch_idal(struct ccwchain *chain,

			       int idx,

			       struct channel_program *cp)

{

	struct ccw1 *ccw;

	struct pfn_array *pa;

	unsigned long *idaws;

	u64 idaw_iova;

	unsigned int idaw_nr, idaw_len;

	int i, ret;

	int bytes = 1;



	ccw = chain->ch_ccw + idx;



	if (ccw->count)

		bytes = ccw->count;



	/* Calculate size of idaws. */

	ret = copy_from_iova(cp->mdev, &idaw_iova, ccw->cda, sizeof(idaw_iova));

	if (ret)

		return ret;

	idaw_nr = idal_nr_words((void *)(idaw_iova), bytes);

	idaw_len = idaw_nr * sizeof(*idaws);



	/* Pin data page(s) in memory. */

	pa = chain->ch_pa + idx;

	ret = pfn_array_alloc(pa, idaw_iova, bytes);

	if (ret)

		goto out_init;



	/* Translate idal ccw to use new allocated idaws. */

	idaws = kzalloc(idaw_len, GFP_DMA | GFP_KERNEL);

	if (!idaws) {

		ret = -ENOMEM;

		goto out_unpin;

	}



	ret = copy_from_iova(cp->mdev, idaws, ccw->cda, idaw_len);

	if (ret)

		goto out_free_idaws;



	ccw->cda = virt_to_phys(idaws);



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

		pa->pa_iova_pfn[i] = idaws[i] >> PAGE_SHIFT;



	if (ccw_does_data_transfer(ccw)) {

		ret = pfn_array_pin(pa, cp->mdev);

		if (ret < 0)

			goto out_free_idaws;

	} else {

		pa->pa_nr = 0;

	}



	pfn_array_idal_create_words(pa, idaws);



	return 0;



out_free_idaws:

	kfree(idaws);

out_unpin:

	pfn_array_unpin_free(pa, cp->mdev);

out_init:

	ccw->cda = 0;

	return ret;

}



/*

 * Fetch one ccw.

 * To reduce memory copy, we'll pin the cda page in memory,
@@ -671,9 +637,6 @@ static int ccwchain_fetch_one(struct ccwchain *chain, 
	if (ccw_is_tic(ccw))

		return ccwchain_fetch_tic(chain, idx, cp);



	if (ccw_is_idal(ccw))

		return ccwchain_fetch_idal(chain, idx, cp);



	return ccwchain_fetch_direct(chain, idx, cp);

}

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