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vfio-ccw: Copy CCW data outside length calculation

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It doesn't make much sense to "hide" the copy to the channel_program
struct inside a routine that calculates the length of the chain.

Let's move it to the calling routine, which will later copy from
channel_program to the memory it allocated itself.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20190618202352.39702-4-farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Eric Farman 2019-06-18 22:23:50 +02:00 committed by Cornelia Huck
parent 6246590230
commit ded563f31d
1 changed files with 7 additions and 12 deletions
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19
drivers/s390/cio/vfio_ccw_cp.c
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@ -381,18 +381,8 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx)
static int ccwchain_calc_length(u64 iova, struct channel_program *cp)
{
struct ccw1 *ccw = cp->guest_cp;
int cnt;
int cnt = 0;
/*
* Copy current chain from guest to host kernel.
* Currently the chain length is limited to CCWCHAIN_LEN_MAX (256).
* So copying 2K is enough (safe).
*/
cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX);
if (cnt)
return cnt;
cnt = 0;
do {
cnt++;
@ -446,7 +436,12 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp)
struct ccwchain *chain;
int len;
/* Copy the chain from cda to cp, and count the CCWs in it */
/* Copy 2K (the most we support today) of possible CCWs */
len = copy_ccw_from_iova(cp, cp->guest_cp, cda, CCWCHAIN_LEN_MAX);
if (len)
return len;
/* Count the CCWs in the current chain */
len = ccwchain_calc_length(cda, cp);
if (len < 0)
return len;