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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: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20190606202831.44135-10-farman@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Eric Farman 2019-06-06 22:28:31 +02:00 committed by Cornelia Huck
parent e8573b39a8
commit 01aa26c672
1 changed files with 39 additions and 76 deletions
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115
drivers/s390/cio/vfio_ccw_cp.c
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@ -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 @@ static int ccwchain_fetch_direct(struct ccwchain *chain,
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);
}