Drivers: hv: vmbus: Remove the per-CPU post_msg_page

The post_msg_page was introduced in 2014 in
commit b29ef3546aec ("Drivers: hv: vmbus: Cleanup hv_post_message()")

Commit 68bb7bfb7985 ("X86/Hyper-V: Enable IPI enlightenments") introduced
the hyperv_pcpu_input_arg in 2018, which can be used in hv_post_message().

Remove post_msg_page to simplify the code a little bit.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Jinank Jain <jinankjain@linux.microsoft.com>
Link: https://lore.kernel.org/r/20230408213441.15472-1-decui@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 008234894d2878ab13d5a42cd6e868d55f2641dd..4e1407d59ba0fbd3d88c3c259fbc57f1510a6984 100644 (file)
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -84,14 +84,15 @@ int hv_post_message(union hv_connection_id connection_id,
                  void *payload, size_t payload_size)
 {
        struct hv_input_post_message *aligned_msg;
-       struct hv_per_cpu_context *hv_cpu;
+       unsigned long flags;
        u64 status;
 
        if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
                return -EMSGSIZE;
 
-       hv_cpu = get_cpu_ptr(hv_context.cpu_context);
-       aligned_msg = hv_cpu->post_msg_page;
+       local_irq_save(flags);
+
+       aligned_msg = *this_cpu_ptr(hyperv_pcpu_input_arg);
        aligned_msg->connectionid = connection_id;
        aligned_msg->reserved = 0;
        aligned_msg->message_type = message_type;
@@ -106,11 +107,7 @@ int hv_post_message(union hv_connection_id connection_id,
                status = hv_do_hypercall(HVCALL_POST_MESSAGE,
                                aligned_msg, NULL);
 
-       /* Preemption must remain disabled until after the hypercall
-        * so some other thread can't get scheduled onto this cpu and
-        * corrupt the per-cpu post_msg_page
-        */
-       put_cpu_ptr(hv_cpu);
+       local_irq_restore(flags);
 
        return hv_result(status);
 }
@@ -162,12 +159,6 @@ int hv_synic_alloc(void)
                                goto err;
                        }
                }
-
-               hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
-               if (hv_cpu->post_msg_page == NULL) {
-                       pr_err("Unable to allocate post msg page\n");
-                       goto err;
-               }
        }
 
        return 0;
@@ -190,7 +181,6 @@ void hv_synic_free(void)
 
                free_page((unsigned long)hv_cpu->synic_event_page);
                free_page((unsigned long)hv_cpu->synic_message_page);
-               free_page((unsigned long)hv_cpu->post_msg_page);
        }
 
        kfree(hv_context.hv_numa_map);

diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 167ac5115a78945255ef9bc4f4aeb8f206e25b34..55f2086841ae41a1493a235aaee4f297601f496c 100644 (file)
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -122,10 +122,6 @@ enum {
 struct hv_per_cpu_context {
        void *synic_message_page;
        void *synic_event_page;
-       /*
-        * buffer to post messages to the host.
-        */
-       void *post_msg_page;
 
        /*
         * Starting with win8, we can take channel interrupts on any CPU;