[PATCH 050/117] Staging: hv: vmbus: Retry vmbus_post_msg() before giving up
From: "K. Y. Srinivasan" <kys@microsoft.com>
Date: 2011-07-15 17:47:45
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Subsystem:
staging subsystem, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Greg Kroah-Hartman, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
The function hv_post_msg() can fail because of transient resource conditions. It may be useful to retry the operation. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> --- arch/x86/include/asm/hyperv.h | 1 + drivers/staging/hv/connection.c | 18 +++++++++++++++++- 2 files changed, 18 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/hyperv.h b/arch/x86/include/asm/hyperv.h
index 5df477a..b80420b 100644
--- a/arch/x86/include/asm/hyperv.h
+++ b/arch/x86/include/asm/hyperv.h@@ -189,5 +189,6 @@ #define HV_STATUS_INVALID_HYPERCALL_CODE 2 #define HV_STATUS_INVALID_HYPERCALL_INPUT 3 #define HV_STATUS_INVALID_ALIGNMENT 4 +#define HV_STATUS_INSUFFICIENT_BUFFERS 19 #endif
diff --git a/drivers/staging/hv/connection.c b/drivers/staging/hv/connection.c
index 0e7efce..a88ad70 100644
--- a/drivers/staging/hv/connection.c
+++ b/drivers/staging/hv/connection.c@@ -25,6 +25,7 @@ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/wait.h> +#include <linux/delay.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/vmalloc.h>
@@ -268,10 +269,25 @@ void vmbus_on_event(unsigned long data) int vmbus_post_msg(void *buffer, size_t buflen) { union hv_connection_id conn_id; + int ret = 0; + int retries = 0; conn_id.asu32 = 0; conn_id.u.id = VMBUS_MESSAGE_CONNECTION_ID; - return hv_post_message(conn_id, 1, buffer, buflen); + + /* + * hv_post_message() can have transient failures because of + * insufficient resources. Retry the operation a couple of + * times before giving up. + */ + while (retries < 3) { + ret = hv_post_message(conn_id, 1, buffer, buflen); + if (ret != HV_STATUS_INSUFFICIENT_BUFFERS) + return ret; + retries++; + msleep(100); + } + return ret; } /*
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1.7.4.1