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| author | K. Y. Srinivasan <kys@microsoft.com> | 2014-08-28 18:29:52 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-23 23:31:21 -0700 |
| commit | b29ef3546aecb253a5552b198cef23750d56e1e4 (patch) | |
| tree | bf19352ffb8926cada04df65ba7c1222797e67bb /drivers/hv/hv.c | |
| parent | 98d731bb064a9d1817a6ca9bf8b97051334a7cfe (diff) | |
| download | linux-next-b29ef3546aecb253a5552b198cef23750d56e1e4.tar.gz | |
Drivers: hv: vmbus: Cleanup hv_post_message()
Minimize failures in this function by pre-allocating the buffer
for posting messages. The hypercall for posting the message can fail
for a number of reasons:
1. Transient resource related issues
2. Buffer alignment
3. Buffer cannot span a page boundry
We address issues 2 and 3 by preallocating a per-cpu page for the buffer.
Transient resource related failures are handled by retrying by the callers
of this function.
This patch is based on the investigation
done by Dexuan Cui <decui@microsoft.com>.
I would like to thank Sitsofe Wheeler <sitsofe@yahoo.com>
for reporting the issue and helping in debuggging.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Cc: <stable@vger.kernel.org>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hv/hv.c')
| -rw-r--r-- | drivers/hv/hv.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c index edfc8488cb03..3e4235c7a47f 100644 --- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -138,6 +138,8 @@ int hv_init(void) memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS); memset(hv_context.synic_message_page, 0, sizeof(void *) * NR_CPUS); + memset(hv_context.post_msg_page, 0, + sizeof(void *) * NR_CPUS); memset(hv_context.vp_index, 0, sizeof(int) * NR_CPUS); memset(hv_context.event_dpc, 0, @@ -217,26 +219,18 @@ int hv_post_message(union hv_connection_id connection_id, enum hv_message_type message_type, void *payload, size_t payload_size) { - struct aligned_input { - u64 alignment8; - struct hv_input_post_message msg; - }; struct hv_input_post_message *aligned_msg; u16 status; - unsigned long addr; if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) return -EMSGSIZE; - addr = (unsigned long)kmalloc(sizeof(struct aligned_input), GFP_ATOMIC); - if (!addr) - return -ENOMEM; - aligned_msg = (struct hv_input_post_message *) - (ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN)); + hv_context.post_msg_page[get_cpu()]; aligned_msg->connectionid = connection_id; + aligned_msg->reserved = 0; aligned_msg->message_type = message_type; aligned_msg->payload_size = payload_size; memcpy((void *)aligned_msg->payload, payload, payload_size); @@ -244,8 +238,7 @@ int hv_post_message(union hv_connection_id connection_id, status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL) & 0xFFFF; - kfree((void *)addr); - + put_cpu(); return status; } @@ -294,6 +287,14 @@ int hv_synic_alloc(void) pr_err("Unable to allocate SYNIC event page\n"); goto err; } + + hv_context.post_msg_page[cpu] = + (void *)get_zeroed_page(GFP_ATOMIC); + + if (hv_context.post_msg_page[cpu] == NULL) { + pr_err("Unable to allocate post msg page\n"); + goto err; + } } return 0; @@ -308,6 +309,8 @@ static void hv_synic_free_cpu(int cpu) free_page((unsigned long)hv_context.synic_event_page[cpu]); if (hv_context.synic_message_page[cpu]) free_page((unsigned long)hv_context.synic_message_page[cpu]); + if (hv_context.post_msg_page[cpu]) + free_page((unsigned long)hv_context.post_msg_page[cpu]); } void hv_synic_free(void) |