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s390/dasd: Extend prepare_itcw() to support WRITE_FULL_TRACK

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prepare_itcw() builds the FCX prefix block (PFX + LRE) for track-mode
I/O. Extend it to handle DASD_ECKD_CCW_WRITE_FULL_TRACK.

WRITE_FULL_TRACK needs two extra bytes appended to the LRE for that
bitmask. The prefix block is a scratch buffer copied into the TCCB by
itcw_add_dcw(), so keep it on the stack (sized for the two extra bytes)
rather than allocating it: this runs in the writeback path and must not
depend on an allocation that can fail under memory pressure.

Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://patch.msgid.link/20260805111612.1285190-11-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Stefan Haberland
2026-08-05 13:16:03 +02:00
committed by Jens Axboe
parent 0569784929
commit 44f9bf4798
1 changed files with 51 additions and 13 deletions
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64
drivers/s390/block/dasd_eckd.c
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@@ -4385,11 +4385,13 @@ static int prepare_itcw(struct itcw *itcw,
unsigned int tlf,
unsigned int blk_per_trk)
{
struct PFX_eckd_data pfxdata;
u8 pfxbuf[sizeof(struct PFX_eckd_data) + 2] __aligned(8);
struct PFX_eckd_data *pfxdata = (struct PFX_eckd_data *)pfxbuf;
struct dasd_eckd_private *basepriv, *startpriv;
struct DE_eckd_data *dedata;
struct LRE_eckd_data *lredata;
struct dcw *dcw;
int pfxsize;
u32 begcyl, endcyl;
u16 heads, beghead, endhead;
@@ -4399,26 +4401,31 @@ static int prepare_itcw(struct itcw *itcw,
int sector = 0;
int dn, d;
pfxsize = sizeof(struct PFX_eckd_data);
/* prefix + LRE extended data */
if (cmd == DASD_ECKD_CCW_WRITE_FULL_TRACK)
pfxsize += 2;
memset(pfxbuf, 0, pfxsize);
/* setup prefix data */
basepriv = basedev->private;
startpriv = startdev->private;
dedata = &pfxdata.define_extent;
lredata = &pfxdata.locate_record;
dedata = &pfxdata->define_extent;
lredata = &pfxdata->locate_record;
memset(&pfxdata, 0, sizeof(pfxdata));
pfxdata.format = 1; /* PFX with LRE */
pfxdata.base_address = basepriv->conf.ned->unit_addr;
pfxdata.base_lss = basepriv->conf.ned->ID;
pfxdata.validity.define_extent = 1;
pfxdata->format = 1; /* PFX with LRE */
pfxdata->base_address = basepriv->conf.ned->unit_addr;
pfxdata->base_lss = basepriv->conf.ned->ID;
pfxdata->validity.define_extent = 1;
/* private uid is kept up to date, conf_data may be outdated */
if (startpriv->uid.type == UA_BASE_PAV_ALIAS)
pfxdata.validity.verify_base = 1;
pfxdata->validity.verify_base = 1;
if (startpriv->uid.type == UA_HYPER_PAV_ALIAS) {
pfxdata.validity.verify_base = 1;
pfxdata.validity.hyper_pav = 1;
pfxdata->validity.verify_base = 1;
pfxdata->validity.hyper_pav = 1;
}
switch (cmd) {
@@ -4448,7 +4455,38 @@ static int prepare_itcw(struct itcw *itcw,
* data as well.
*/
if (dedata->ga_extended & 0x08 && dedata->ga_extended & 0x02)
pfxdata.validity.time_stamp = 1; /* 'Time Stamp Valid' */
pfxdata->validity.time_stamp = 1; /* 'Time Stamp Valid' */
pfx_cmd = DASD_ECKD_CCW_PFX;
break;
case DASD_ECKD_CCW_WRITE_FULL_TRACK:
dedata->mask.perm = 0x3;
dedata->mask.auth = 0x00;
dedata->attributes.operation = basepriv->attrib.operation;
dedata->blk_size = blksize;
dedata->ga_extended |= 0x42;
rc = set_timestamp(NULL, dedata, basedev);
lredata->operation.orientation = 0x0;
lredata->operation.operation = 0x3F;
lredata->extended_operation = 0x11;
lredata->auxiliary.check_bytes = 0x2;
lredata->extended_parameter_length = 0x02;
if (count > 8) {
lredata->extended_parameter[0] = 0xFF;
lredata->extended_parameter[1] = 0xFF;
lredata->extended_parameter[1] <<= (16 - count);
} else {
lredata->extended_parameter[0] = 0xFF;
lredata->extended_parameter[0] <<= (8 - count);
lredata->extended_parameter[1] = 0x00;
}
sector = 0xFF;
/*
* If XRC is supported the System Time Stamp is set. The
* validity of the time stamp must be reflected in the prefix
* data as well.
*/
if (dedata->ga_extended & 0x08 && dedata->ga_extended & 0x02)
pfxdata->validity.time_stamp = 1; /* 'Time Stamp Valid' */
pfx_cmd = DASD_ECKD_CCW_PFX;
break;
case DASD_ECKD_CCW_READ_COUNT_MT:
@@ -4527,7 +4565,7 @@ static int prepare_itcw(struct itcw *itcw,
lredata->search_arg.record = rec_on_trk;
dcw = itcw_add_dcw(itcw, pfx_cmd, 0,
&pfxdata, sizeof(pfxdata), total_data_size);
pfxdata, pfxsize, total_data_size);
return PTR_ERR_OR_ZERO(dcw);
}