s390/cio: fix accidental interrupt enabling during resume

commit d53c51f26145657aa7c55fa396f93677e613548d upstream.

Since commit 9f3d6d7 chsc_get_channel_measurement_chars is called with
interrupts disabled during resume from hibernate. Since this function
used spin_unlock_irq, interrupts have been enabled accidentally. Fix
this by using the irqsave variant.

Since we can't guarantee the IRQ-enablement state for all (future/
external) callers, change the locking in related functions to prevent
similar bugs in the future.

Fixes: 9f3d6d7 ("s390/cio: update measurement characteristics")
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index c424c0c7367e360acd9ccd1ce899dc80bb575265..1e16331891a9426fdca1d99f5c4ae8a043f34742 100644 (file)
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -95,12 +95,13 @@ struct chsc_ssd_area {
 int chsc_get_ssd_info(struct subchannel_id schid, struct chsc_ssd_info *ssd)
 {
        struct chsc_ssd_area *ssd_area;
+       unsigned long flags;
        int ccode;
        int ret;
        int i;
        int mask;
 
-       spin_lock_irq(&chsc_page_lock);
+       spin_lock_irqsave(&chsc_page_lock, flags);
        memset(chsc_page, 0, PAGE_SIZE);
        ssd_area = chsc_page;
        ssd_area->request.length = 0x0010;
@@ -144,7 +145,7 @@ int chsc_get_ssd_info(struct subchannel_id schid, struct chsc_ssd_info *ssd)
                        ssd->fla[i] = ssd_area->fla[i];
        }
 out:
-       spin_unlock_irq(&chsc_page_lock);
+       spin_unlock_irqrestore(&chsc_page_lock, flags);
        return ret;
 }
 
@@ -832,9 +833,10 @@ int __chsc_do_secm(struct channel_subsystem *css, int enable)
                u32 fmt : 4;
                u32 : 16;
        } __attribute__ ((packed)) *secm_area;
+       unsigned long flags;
        int ret, ccode;
 
-       spin_lock_irq(&chsc_page_lock);
+       spin_lock_irqsave(&chsc_page_lock, flags);
        memset(chsc_page, 0, PAGE_SIZE);
        secm_area = chsc_page;
        secm_area->request.length = 0x0050;
@@ -864,7 +866,7 @@ int __chsc_do_secm(struct channel_subsystem *css, int enable)
                CIO_CRW_EVENT(2, "chsc: secm failed (rc=%04x)\n",
                              secm_area->response.code);
 out:
-       spin_unlock_irq(&chsc_page_lock);
+       spin_unlock_irqrestore(&chsc_page_lock, flags);
        return ret;
 }
 
@@ -993,6 +995,7 @@ chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,
 
 int chsc_get_channel_measurement_chars(struct channel_path *chp)
 {
+       unsigned long flags;
        int ccode, ret;
 
        struct {
@@ -1022,7 +1025,7 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
        if (!css_chsc_characteristics.scmc || !css_chsc_characteristics.secm)
                return 0;
 
-       spin_lock_irq(&chsc_page_lock);
+       spin_lock_irqsave(&chsc_page_lock, flags);
        memset(chsc_page, 0, PAGE_SIZE);
        scmc_area = chsc_page;
        scmc_area->request.length = 0x0010;
@@ -1054,7 +1057,7 @@ int chsc_get_channel_measurement_chars(struct channel_path *chp)
        chsc_initialize_cmg_chars(chp, scmc_area->cmcv,
                                  (struct cmg_chars *) &scmc_area->data);
 out:
-       spin_unlock_irq(&chsc_page_lock);
+       spin_unlock_irqrestore(&chsc_page_lock, flags);
        return ret;
 }
 
@@ -1135,6 +1138,7 @@ struct css_chsc_char css_chsc_characteristics;
 int __init
 chsc_determine_css_characteristics(void)
 {
+       unsigned long flags;
        int result;
        struct {
                struct chsc_header request;
@@ -1147,7 +1151,7 @@ chsc_determine_css_characteristics(void)
                u32 chsc_char[508];
        } __attribute__ ((packed)) *scsc_area;
 
-       spin_lock_irq(&chsc_page_lock);
+       spin_lock_irqsave(&chsc_page_lock, flags);
        memset(chsc_page, 0, PAGE_SIZE);
        scsc_area = chsc_page;
        scsc_area->request.length = 0x0010;
@@ -1169,7 +1173,7 @@ chsc_determine_css_characteristics(void)
                CIO_CRW_EVENT(2, "chsc: scsc failed (rc=%04x)\n",
                              scsc_area->response.code);
 exit:
-       spin_unlock_irq(&chsc_page_lock);
+       spin_unlock_irqrestore(&chsc_page_lock, flags);
        return result;
 }