| Message ID | 20230530125243.18883-3-pmorel@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fixing infinite loop on SCLP READ SCP INFO error | expand |
On Tue, 30 May 2023 14:52:43 +0200 Pierre Morel <pmorel@linux.ibm.com> wrote: > If SCLP_CMDW_READ_SCP_INFO fails due to a short buffer, retry > with a greater buffer. the idea is good, but I wonder if the code can be simplified (see below) > > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> > --- > lib/s390x/sclp.c | 58 +++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 50 insertions(+), 8 deletions(-) > > diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c > index 34a31da..9d51ca4 100644 > --- a/lib/s390x/sclp.c > +++ b/lib/s390x/sclp.c > @@ -17,13 +17,14 @@ > #include "sclp.h" > #include <alloc_phys.h> > #include <alloc_page.h> > +#include <asm/facility.h> > > extern unsigned long stacktop; > > static uint64_t storage_increment_size; > static uint64_t max_ram_size; > static uint64_t ram_size; > -char _read_info[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); > +char _read_info[2 * PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); this is ok ^ [skip everything else] > void sclp_read_info(void) > { > - sclp_read_scp_info((void *)_read_info, SCCB_SIZE); sclp_read_scp_info((void *)_read_info, test_facility(140) ? sizeof(_read_info) : SCCB_SIZE; > + sclp_read_scp_info((void *)_read_info); > read_info = (ReadInfo *)_read_info; > } >
On 5/30/23 17:35, Claudio Imbrenda wrote: > On Tue, 30 May 2023 14:52:43 +0200 > Pierre Morel <pmorel@linux.ibm.com> wrote: > >> If SCLP_CMDW_READ_SCP_INFO fails due to a short buffer, retry >> with a greater buffer. > the idea is good, but I wonder if the code can be simplified (see below) > >> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> >> --- >> lib/s390x/sclp.c | 58 +++++++++++++++++++++++++++++++++++++++++------- >> 1 file changed, 50 insertions(+), 8 deletions(-) >> >> diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c >> index 34a31da..9d51ca4 100644 >> --- a/lib/s390x/sclp.c >> +++ b/lib/s390x/sclp.c >> @@ -17,13 +17,14 @@ >> #include "sclp.h" >> #include <alloc_phys.h> >> #include <alloc_page.h> >> +#include <asm/facility.h> >> >> extern unsigned long stacktop; >> >> static uint64_t storage_increment_size; >> static uint64_t max_ram_size; >> static uint64_t ram_size; >> -char _read_info[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); >> +char _read_info[2 * PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); > this is ok ^ > > [skip everything else] > >> void sclp_read_info(void) >> { >> - sclp_read_scp_info((void *)_read_info, SCCB_SIZE); > sclp_read_scp_info((void *)_read_info, > test_facility(140) ? sizeof(_read_info) : SCCB_SIZE; > >> + sclp_read_scp_info((void *)_read_info); >> read_info = (ReadInfo *)_read_info; >> } >> You are right, no need to begin with a short buffer if we can go with a big one at first try. I take it thx
diff --git a/lib/s390x/sclp.c b/lib/s390x/sclp.c index 34a31da..9d51ca4 100644 --- a/lib/s390x/sclp.c +++ b/lib/s390x/sclp.c @@ -17,13 +17,14 @@ #include "sclp.h" #include <alloc_phys.h> #include <alloc_page.h> +#include <asm/facility.h> extern unsigned long stacktop; static uint64_t storage_increment_size; static uint64_t max_ram_size; static uint64_t ram_size; -char _read_info[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); +char _read_info[2 * PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); static ReadInfo *read_info; struct sclp_facilities sclp_facilities; @@ -89,10 +90,41 @@ void sclp_clear_busy(void) spin_unlock(&sclp_lock); } -static void sclp_read_scp_info(ReadInfo *ri, int length) +static bool sclp_read_scp_info_extended(unsigned int command, ReadInfo *ri) +{ + int cc; + + if (!test_facility(140)) { + report_abort("S390_FEAT_EXTENDED_LENGTH_SCCB missing"); + return false; + } + if (ri->h.length > (2 * PAGE_SIZE)) { + report_abort("SCLP_READ_INFO expected size too big"); + return false; + } + + sclp_mark_busy(); + memset(&ri->h, 0, sizeof(ri->h)); + ri->h.length = 2 * PAGE_SIZE; + + cc = sclp_service_call(command, ri); + if (cc) { + report_abort("SCLP_READ_INFO error"); + return false; + } + if (ri->h.response_code != SCLP_RC_NORMAL_READ_COMPLETION) { + report_abort("SCLP_READ_INFO error %02x", ri->h.response_code); + return false; + } + + return true; +} + +static void sclp_read_scp_info(ReadInfo *ri) { unsigned int commands[] = { SCLP_CMDW_READ_SCP_INFO_FORCED, SCLP_CMDW_READ_SCP_INFO }; + int length = PAGE_SIZE; int i, cc; for (i = 0; i < ARRAY_SIZE(commands); i++) { @@ -101,19 +133,29 @@ static void sclp_read_scp_info(ReadInfo *ri, int length) ri->h.length = length; cc = sclp_service_call(commands[i], ri); - if (cc) - break; - if (ri->h.response_code == SCLP_RC_NORMAL_READ_COMPLETION) + if (cc) { + report_abort("SCLP_READ_INFO error"); return; - if (ri->h.response_code != SCLP_RC_INVALID_SCLP_COMMAND) + } + + switch (ri->h.response_code) { + case SCLP_RC_NORMAL_READ_COMPLETION: + return; + case SCLP_RC_INVALID_SCLP_COMMAND: break; + case SCLP_RC_INSUFFICIENT_SCCB_LENGTH: + sclp_read_scp_info_extended(commands[i], ri); + return; + default: + report_abort("READ_SCP_INFO failed"); + return; + } } - report_abort("READ_SCP_INFO failed"); } void sclp_read_info(void) { - sclp_read_scp_info((void *)_read_info, SCCB_SIZE); + sclp_read_scp_info((void *)_read_info); read_info = (ReadInfo *)_read_info; }
If SCLP_CMDW_READ_SCP_INFO fails due to a short buffer, retry with a greater buffer. Signed-off-by: Pierre Morel <pmorel@linux.ibm.com> --- lib/s390x/sclp.c | 58 +++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 50 insertions(+), 8 deletions(-)