Merge tag 'for-linus-4.7b-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen bug fixes from David Vrabel:

 - Fix two bugs in the handling of xenbus transactions.

 - Make the xen acpi driver compatible with Xen 4.7.

* tag 'for-linus-4.7b-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/acpi: allow xen-acpi-processor driver to load on Xen 4.7
  xenbus: simplify xenbus_dev_request_and_reply()
  xenbus: don't bail early from xenbus_dev_request_and_reply()
  xenbus: don't BUG() on user mode induced condition

3 files changed, 14 insertions, 45 deletions

diff --git a/drivers/xen/xen-acpi-processor.c b/drivers/xen/xen-acpi-processor.c
index 076970a54f89..4ce10bcca18b 100644
--- a/drivers/xen/xen-acpi-processor.c
+++ b/drivers/xen/xen-acpi-processor.c
@@ -423,36 +423,7 @@ upload:
 
         return 0;
 }
-static int __init check_prereq(void)
-{
-        struct cpuinfo_x86 *c = &cpu_data(0);
-
-        if (!xen_initial_domain())
-                return -ENODEV;
-
-        if (!acpi_gbl_FADT.smi_command)
-                return -ENODEV;
-
-        if (c->x86_vendor == X86_VENDOR_INTEL) {
-                if (!cpu_has(c, X86_FEATURE_EST))
-                        return -ENODEV;
 
-                return 0;
-        }
-        if (c->x86_vendor == X86_VENDOR_AMD) {
-                /* Copied from powernow-k8.h, can't include ../cpufreq/powernow
-                 * as we get compile warnings for the static functions.
-                 */
-#define CPUID_FREQ_VOLT_CAPABILITIES    0x80000007
-#define USE_HW_PSTATE                   0x00000080
-                u32 eax, ebx, ecx, edx;
-                cpuid(CPUID_FREQ_VOLT_CAPABILITIES, &eax, &ebx, &ecx, &edx);
-                if ((edx & USE_HW_PSTATE) != USE_HW_PSTATE)
-                        return -ENODEV;
-                return 0;
-        }
-        return -ENODEV;
-}
 /* acpi_perf_data is a pointer to percpu data. */
 static struct acpi_processor_performance __percpu *acpi_perf_data;
 
@@ -509,10 +480,10 @@ struct notifier_block xen_acpi_processor_resume_nb = {
 static int __init xen_acpi_processor_init(void)
 {
         unsigned int i;
-        int rc = check_prereq();
+        int rc;
 
-        if (rc)
-                return rc;
+        if (!xen_initial_domain())
+                return -ENODEV;
 
         nr_acpi_bits = get_max_acpi_id() + 1;
         acpi_ids_done = kcalloc(BITS_TO_LONGS(nr_acpi_bits), sizeof(unsigned long), GFP_KERNEL);
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index cacf30d14747..7487971f9f78 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -316,11 +316,18 @@ static int xenbus_write_transaction(unsigned msg_type,
                         rc = -ENOMEM;
                         goto out;
                 }
+        } else {
+                list_for_each_entry(trans, &u->transactions, list)
+                        if (trans->handle.id == u->u.msg.tx_id)
+                                break;
+                if (&trans->list == &u->transactions)
+                        return -ESRCH;
         }
 
         reply = xenbus_dev_request_and_reply(&u->u.msg);
         if (IS_ERR(reply)) {
-                kfree(trans);
+                if (msg_type == XS_TRANSACTION_START)
+                        kfree(trans);
                 rc = PTR_ERR(reply);
                 goto out;
         }
@@ -333,12 +340,7 @@ static int xenbus_write_transaction(unsigned msg_type,
                         list_add(&trans->list, &u->transactions);
                 }
         } else if (u->u.msg.type == XS_TRANSACTION_END) {
-                list_for_each_entry(trans, &u->transactions, list)
-                        if (trans->handle.id == u->u.msg.tx_id)
-                                break;
-                BUG_ON(&trans->list == &u->transactions);
                 list_del(&trans->list);
-
                 kfree(trans);
         }
 
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index 374b12af8812..22f7cd711c57 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -232,10 +232,10 @@ static void transaction_resume(void)
 void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 {
         void *ret;
-        struct xsd_sockmsg req_msg = *msg;
+        enum xsd_sockmsg_type type = msg->type;
         int err;
 
-        if (req_msg.type == XS_TRANSACTION_START)
+        if (type == XS_TRANSACTION_START)
                 transaction_start();
 
         mutex_lock(&xs_state.request_mutex);
@@ -249,12 +249,8 @@ void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 
         mutex_unlock(&xs_state.request_mutex);
 
-        if (IS_ERR(ret))
-                return ret;
-
         if ((msg->type == XS_TRANSACTION_END) ||
-            ((req_msg.type == XS_TRANSACTION_START) &&
-             (msg->type == XS_ERROR)))
+            ((type == XS_TRANSACTION_START) && (msg->type == XS_ERROR)))
                 transaction_end();
 
         return ret;