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pc-bios/s390-ccw: Break up virtio-scsi read into multiples 

A virtio-scsi request that goes through the host sd driver and exceeds
the maximum transfer size is automatically broken up for us.  But the
equivalent request going to the sg driver presumes that any length
requirements have already been honored.

Let's use the max_sectors field on the virtio-scsi controller device,
and break up all requests (both sd and sg) to avoid this problem.

Signed-off-by: Eric Farman <farman@linux.vnet.ibm.com>
Message-Id: <20170510155359.32727-4-farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Eric Farman 2017-05-10 17:53:54 +02:00 committed by Cornelia Huck
parent 98d3c52435
commit 5ffd4a3c2d
2 changed files with 21 additions and 4 deletions
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7
pc-bios/s390-ccw/s390-ccw.h
View File

@ -42,6 +42,13 @@ typedef unsigned long long __u64;
#ifndef NULL
#define NULL 0
#endif
#ifndef MIN
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif
#ifndef MIN_NON_ZERO
#define MIN_NON_ZERO(a, b) ((a) == 0 ? (b) : \
((b) == 0 ? (a) : (MIN(a, b))))
#endif
#include "cio.h"
#include "iplb.h"

18
pc-bios/s390-ccw/virtio-scsi.c
View File

@ -202,6 +202,7 @@ static void virtio_scsi_locate_device(VDev *vdev)
debug_print_int("config.scsi.max_channel", vdev->config.scsi.max_channel);
debug_print_int("config.scsi.max_target ", vdev->config.scsi.max_target);
debug_print_int("config.scsi.max_lun ", vdev->config.scsi.max_lun);
debug_print_int("config.scsi.max_sectors", vdev->config.scsi.max_sectors);
if (vdev->scsi_device_selected) {
sdev->channel = vdev->selected_scsi_device.channel;
@ -254,12 +255,21 @@ static void virtio_scsi_locate_device(VDev *vdev)
int virtio_scsi_read_many(VDev *vdev,
ulong sector, void *load_addr, int sec_num)
{
int sector_count;
int f = vdev->blk_factor;
unsigned int data_size = sec_num * virtio_get_block_size() * f;
unsigned int data_size;
if (!scsi_read_10(vdev, sector * f, sec_num * f, load_addr, data_size)) {
virtio_scsi_verify_response(&resp, "virtio-scsi:read_many");
}
do {
sector_count = MIN_NON_ZERO(sec_num, vdev->config.scsi.max_sectors);
data_size = sector_count * virtio_get_block_size() * f;
if (!scsi_read_10(vdev, sector * f, sector_count * f, load_addr,
data_size)) {
virtio_scsi_verify_response(&resp, "virtio-scsi:read_many");
}
load_addr += data_size;
sector += sector_count;
sec_num -= sector_count;
} while (sec_num > 0);
return 0;
}