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| author | Sumanth Korikkar <sumanthk@linux.ibm.com> | 2020-11-11 01:03:02 -0600 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2020-11-18 12:16:02 +0100 |
| commit | b971cbd03ee0a24f7af47b681e8f911794c69780 (patch) | |
| tree | e5eaec17dc4235384324ad7302f1031da587f66f /drivers/s390/char/sclp_cmd.c | |
| parent | d25d23e134a43457759fa602a15c1e9fce741727 (diff) | |
| download | lwn-b971cbd03ee0a24f7af47b681e8f911794c69780.tar.gz lwn-b971cbd03ee0a24f7af47b681e8f911794c69780.zip | |
s390/sclp: provide extended sccb support
As the number of cpus increases, the sccb response can exceed 4k for
read cpu and read scp info sclp commands. Hence, all cpu info entries
cant be embedded within a sccb response
Solution:
To overcome this limitation, extended sccb facility is provided by sclp.
1. Check if the extended sccb facility is installed.
2. If extended sccb is installed, perform the read scp and read cpu
command considering a max sccb length of three page size. This max
length is based on factors like max cpus, sccb header.
3. If extended sccb is not installed, perform the read scp and read cpu
sclp command considering a max sccb length of one page size.
Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'drivers/s390/char/sclp_cmd.c')
| -rw-r--r-- | drivers/s390/char/sclp_cmd.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c index f6e97f0830f6..7ebe89890a9b 100644 --- a/drivers/s390/char/sclp_cmd.c +++ b/drivers/s390/char/sclp_cmd.c @@ -27,6 +27,7 @@ #include <asm/page.h> #include <asm/sclp.h> #include <asm/numa.h> +#include <asm/facility.h> #include "sclp.h" @@ -87,14 +88,17 @@ out: int _sclp_get_core_info(struct sclp_core_info *info) { int rc; + int length = test_facility(140) ? EXT_SCCB_READ_CPU : PAGE_SIZE; struct read_cpu_info_sccb *sccb; if (!SCLP_HAS_CPU_INFO) return -EOPNOTSUPP; - sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); + + sccb = (void *)__get_free_pages(GFP_KERNEL | GFP_DMA | __GFP_ZERO, get_order(length)); if (!sccb) return -ENOMEM; - sccb->header.length = sizeof(*sccb); + sccb->header.length = length; + sccb->header.control_mask[2] = 0x80; rc = sclp_sync_request_timeout(SCLP_CMDW_READ_CPU_INFO, sccb, SCLP_QUEUE_INTERVAL); if (rc) @@ -107,7 +111,7 @@ int _sclp_get_core_info(struct sclp_core_info *info) } sclp_fill_core_info(info, sccb); out: - free_page((unsigned long) sccb); + free_pages((unsigned long) sccb, get_order(length)); return rc; } |