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s390/dasd: fix read device characteristic with CONFIG_VMAP_STACK=y 

The dasd_eckd_restore_device() function calls dasd_generic_read_dev_chars
with a temporary buffer on the stack. With CONFIG_VMAP_STACK=y this is
a vmalloc address but dasd_generic_restore_device() uses the address of
the buffer as I/O address. Circumvent this by using the already allocated
cqr->data buffer for the RDC data.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2019-03-01 16:03:47 +01:00
parent c8e8ed386a
commit 9fe567d09f
1 changed files with 5 additions and 14 deletions
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19
drivers/s390/block/dasd.c
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@ -3965,13 +3965,11 @@ int dasd_generic_restore_device(struct ccw_device *cdev)
EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
void *rdc_buffer,
int rdc_buffer_size,
int magic)
{
struct dasd_ccw_req *cqr;
struct ccw1 *ccw;
unsigned long *idaw;
cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device,
NULL);
@ -3986,16 +3984,8 @@ static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
ccw = cqr->cpaddr;
ccw->cmd_code = CCW_CMD_RDC;
if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
idaw = (unsigned long *) (cqr->data);
ccw->cda = (__u32)(addr_t) idaw;
ccw->flags = CCW_FLAG_IDA;
idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
} else {
ccw->cda = (__u32)(addr_t) rdc_buffer;
ccw->flags = 0;
}
ccw->cda = (__u32)(addr_t) cqr->data;
ccw->flags = 0;
ccw->count = rdc_buffer_size;
cqr->startdev = device;
cqr->memdev = device;
@ -4013,12 +4003,13 @@ int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
int ret;
struct dasd_ccw_req *cqr;
cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
magic);
cqr = dasd_generic_build_rdc(device, rdc_buffer_size, magic);
if (IS_ERR(cqr))
return PTR_ERR(cqr);
ret = dasd_sleep_on(cqr);
if (ret == 0)
memcpy(rdc_buffer, cqr->data, rdc_buffer_size);
dasd_sfree_request(cqr, cqr->memdev);
return ret;
}